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Autoimmunity’s Female Bias and the Mysteries of Xist
Female bias in autoimmune disease can be profound, with nine females developing lupus for every male affected, and nearly twice that ratio seen in Sjögren disease.
For years, researchers have worked to determine the reasons for sex-linked differences in immune response and autoimmunity, with environmental factors, sex hormones, and X-chromosome inactivation — the process by which a second X chromosome is silenced — all seen as having roles.
More recently, different groups of researchers have homed in on a long noncoding RNA fragment called X-inactive specific transcript, or Xist, as a potential driver of sex bias in autoimmune disease. Xist, which occurs in female mammals, has been known since the 1990s as the master regulator of X-chromosome inactivation, the process by which the second X chromosome is silenced, averting a fatal double dose of X-linked genes.
The inactivation process, which scientists liken to wrapping the extra X with a fluffy cloud of proteins, occurs early in embryonic development. After its initial work silencing the X, Xist is produced throughout the female’s life, allowing X inactivation to be maintained.
But is it possible that Xist, and the many dozens of proteins it recruits to keep that extra X chromosome silent, can also provoke autoimmunity? This is the question that several teams of researchers have been grappling with, resulting in provocative findings and opening exciting new avenues of discovery.
Xist Protein Complexes Make Male Mice Vulnerable to Lupus
In February, researchers Howard Chang, MD, PhD, and Diana Dou, PhD, of Stanford University in Stanford, California, made worldwide news when they published results from an experiment using male mice genetically engineered to carry a non-silencing form of Xist on one of their chromosomes.
Xist acts like a scaffold, recruiting multiple protein complexes to help it do its job. Dr. Dou explained in an interview that her team has been eyeing suspiciously for years the dozens of proteins Xist recruits in the process of X-chromosome inactivation, many of which are known autoantigens.
When the mice were injected with pristane, a chemical that induces lupus-like autoimmunity in mice, the Xist-producing males developed symptoms at a rate similar to that of females, while wild-type male mice did not.
By using a male model, the scientists could determine whether Xist could cause an increased vulnerability for autoimmunity absent the influence of female hormones and development. “Everything else about the animal is male,” Dr. Dou commented. “You just add the formation of the Xist ribonucleoprotein particles — Xist RNA plus the associating proteins — to male cells that would not ordinarily have these particles. Is just having the particles present in these animals sufficient to increase their autoimmunity? This is what our paper showed: That just having expression of Xist, the presence of these Xist [ribonucleoproteins], is enough in permissive genetic backgrounds to invoke higher incidence and severity of autoimmune disease development in our pristane-induced lupus model.”
The Stanford group sees the Xist protein complex, which they have studied extensively, as a key to understanding how Xist might provoke autoimmunity. Nonetheless, Dr. Dou said, “It’s important to note that there are other contributing factors, which is why not all females develop autoimmunity, and we had very different results in our autoimmune-resistant mouse strain compared to the more autoimmune-prone strain. Xist is a factor, but many factors are required to subvert the checkpoints in immune balance and allow the progression to full-blown autoimmunity.”
Faulty X Inactivation and Gene Escape
The understanding that Xist might be implicated in autoimmune disease — and explain some of its female bias — is not new.
About a decade ago, Montserrat Anguera, PhD, a biologist at the University of Pennsylvania, Philadelphia, began looking at the relationship of X-chromosome inactivation, which by definition involves Xist, and lupus.
Dr. Anguera hypothesized that imperfect X inactivation allowed for greater escape of genes associated with immunity and autoimmunity. Studying patients with lupus, Dr. Anguera found that the silencing process was abnormal, allowing more of these genes to escape the silenced X — including toll-like receptor 7 (TLR-7) and other genes implicated in the pathogenesis of lupus.
“If you get increased expression of certain genes from the [silenced] X, like TLR-7, it can result in autoimmune disease,” Dr. Anguera said. “So what we think is that in the lupus patients, because the silencing is impacted, you’re going to have more expression happening from the inactive X. And then in conjunction with the active X, that’s going to throw off the dosage [of autoimmunity-linked genes]. You’re changing the dosage of genes, and that’s what’s critical.”
Even among patients with lupus whose symptoms are well controlled with medication, “if you look at their T cells and B cells, they still have messed up X inactivation,” Dr. Anguera said. “The Xist RNA that’s supposed to be tethered to the inactive X in a fluffy cloud is not localized, and instead is dispersed all over the nucleus.”
Dr. Anguera pointed out that autoimmune diseases are complex and can result from a combination of factors. “You also have a host of hormonal and environmental contributors, such as previous viral infections,” she said. And of course men can also develop lupus, meaning that the X chromosome cannot explain everything.
Dr. Anguera said that, while the findings by the Stanford scientists do not explain the full pathogenesis of lupus and related diseases, they still support a strong role for Xist in sex-biased autoimmune diseases. “It’s sort of another take on it,” she said.
Is It the Proteins, the RNA, or Both?
The Stanford team points to the proteins recruited by Xist in the process of X-chromosome inactivation as the likely trigger of autoimmunity. However, a group of researchers at Johns Hopkins University in Baltimore, Maryland, made the case in a 2022 paper that Xist RNA itself was dangerous. They found that numerous short RNA sequences within the Xist molecule serve as ligands for TLR-7. And TLR-7 ligation causes plasmacytoid dendritic cells to overproduce type 1 interferon, a classic hallmark of lupus.
“Within rheumatology, the diseases that tend to be most female biased are the ones that are antibody positive and have this presence of upregulated interferon,” explained Brendan Antiochos, MD. “Lupus is an example of that. Sjögren’s syndrome is another. So there’s always been this quest to want to understand the mechanisms that explain why women would have more autoimmunity. And are there specific pathways which could contribute? One of the key pathways that’s been shown in humans and in mice to be important in lupus is toll-like receptor signaling.” Most convincingly, one recent study showed that people who have a gain-of-function mutation in their TLR-7 gene get a spontaneous form of lupus.
These findings led Erika Darrah, PhD, and her colleague Dr. Antiochos to begin looking more deeply into which RNAs could be triggering this signaling pathway. “We started to think: Well, there is this sex bias. Could it be that women have unique RNAs that could potentially act as triggers for TLR-7 signaling?” Dr. Darrah said.
Dr. Darrah and Dr. Antiochos looked at publicly available genetic data to identify sex-biased sources of self-RNA containing TLR-7 ligands. Xist, they found, was chock full of them. “Every time we analyzed that data, no matter what filter we applied, Xist kept popping out over and over again as the most highly female skewed RNA, the RNA most likely to contain these TLR-7 binding motifs,” Dr. Darrah said. “We started to formulate the hypothesis that Xist was actually promoting responses that were dangerous and pathogenic in lupus.”
That finding led the team to conduct in-vitro experiments that showed different fragments of Xist can activate TLR-7, resulting in higher interferon production. Finally, they looked at blood and kidney cells from women with lupus and found that higher Xist expression correlated with more interferon production, and higher disease activity. “The more Xist, the sicker people were,” Dr. Darrah said.
Xist’s Other Functions
Xist was first studied in the 1990s, and most research has centered on its primary role in X-chromosome inactivation. A research group led by Kathrin Plath, PhD, at the University of California, Los Angeles, has been occupied for years with untangling exactly how Xist does what it does. “It’s a very clever RNA, right? It can silence the whole chromosome,” Dr. Plath said in an interview.
In 2021, Dr. Plath and her colleagues established in detail how Xist executes silencing, setting down pairs of molecules in specific spots along the chromosome and building huge protein clouds around them. “We worked on learning where Xist binds and what proteins it binds, drilling down to understand how these proteins and the RNA are coming together.”
Dr. Plath has long suspected that Xist has other functions besides X inactivation, and she and her colleagues are starting to identify them. Early this year they published the surprising finding that Xist can regulate gene expression in autosomes, or non–sex-linked chromosomes, “which it might well also do in cancer cells and lymphocytes,” Dr. Plath said. “And now there is this new evidence of an autoimmune function,” she said. “It’s a super exciting time.”
The different hypotheses surrounding Xist’s role in sex-biased autoimmunity aren’t mutually exclusive, Dr. Plath said. “There’s a tremendous enrichment of proteins occurring” during X inactivation, she said, supporting the Stanford team’s hypothesis that proteins are triggering autoimmunity. As for the Johns Hopkins researchers’ understanding that Xist RNA itself is the trigger, “I’m totally open to that,” she said. “Why can’t it be an autoantigen?”
The other model in the field, Dr. Plath noted, is the one proposed by Dr. Anguera — “that there’s [gene] escape from X-inactivation — that females have more escape expression, and that Xist is more dispersed in the lymphocytes [of patients with lupus]. In fact, Xist becoming a little dispersed might make it a better antigen. So I do think everything is possible.”
The plethora of new findings related to autoimmunity has caused Dr. Plath to consider redirecting her lab’s focus toward more translational work, “because we are obviously good at studying Xist.” Among the mysteries Dr. Plath would like to solve is how some genes manage to escape the Xist cloud.
What is needed, she said, is collaboration. “Everyone will come up with different ideas. So I think it’s good to have more people look at things together. Then the field will achieve a breakthrough treatment.”
Female bias in autoimmune disease can be profound, with nine females developing lupus for every male affected, and nearly twice that ratio seen in Sjögren disease.
For years, researchers have worked to determine the reasons for sex-linked differences in immune response and autoimmunity, with environmental factors, sex hormones, and X-chromosome inactivation — the process by which a second X chromosome is silenced — all seen as having roles.
More recently, different groups of researchers have homed in on a long noncoding RNA fragment called X-inactive specific transcript, or Xist, as a potential driver of sex bias in autoimmune disease. Xist, which occurs in female mammals, has been known since the 1990s as the master regulator of X-chromosome inactivation, the process by which the second X chromosome is silenced, averting a fatal double dose of X-linked genes.
The inactivation process, which scientists liken to wrapping the extra X with a fluffy cloud of proteins, occurs early in embryonic development. After its initial work silencing the X, Xist is produced throughout the female’s life, allowing X inactivation to be maintained.
But is it possible that Xist, and the many dozens of proteins it recruits to keep that extra X chromosome silent, can also provoke autoimmunity? This is the question that several teams of researchers have been grappling with, resulting in provocative findings and opening exciting new avenues of discovery.
Xist Protein Complexes Make Male Mice Vulnerable to Lupus
In February, researchers Howard Chang, MD, PhD, and Diana Dou, PhD, of Stanford University in Stanford, California, made worldwide news when they published results from an experiment using male mice genetically engineered to carry a non-silencing form of Xist on one of their chromosomes.
Xist acts like a scaffold, recruiting multiple protein complexes to help it do its job. Dr. Dou explained in an interview that her team has been eyeing suspiciously for years the dozens of proteins Xist recruits in the process of X-chromosome inactivation, many of which are known autoantigens.
When the mice were injected with pristane, a chemical that induces lupus-like autoimmunity in mice, the Xist-producing males developed symptoms at a rate similar to that of females, while wild-type male mice did not.
By using a male model, the scientists could determine whether Xist could cause an increased vulnerability for autoimmunity absent the influence of female hormones and development. “Everything else about the animal is male,” Dr. Dou commented. “You just add the formation of the Xist ribonucleoprotein particles — Xist RNA plus the associating proteins — to male cells that would not ordinarily have these particles. Is just having the particles present in these animals sufficient to increase their autoimmunity? This is what our paper showed: That just having expression of Xist, the presence of these Xist [ribonucleoproteins], is enough in permissive genetic backgrounds to invoke higher incidence and severity of autoimmune disease development in our pristane-induced lupus model.”
The Stanford group sees the Xist protein complex, which they have studied extensively, as a key to understanding how Xist might provoke autoimmunity. Nonetheless, Dr. Dou said, “It’s important to note that there are other contributing factors, which is why not all females develop autoimmunity, and we had very different results in our autoimmune-resistant mouse strain compared to the more autoimmune-prone strain. Xist is a factor, but many factors are required to subvert the checkpoints in immune balance and allow the progression to full-blown autoimmunity.”
Faulty X Inactivation and Gene Escape
The understanding that Xist might be implicated in autoimmune disease — and explain some of its female bias — is not new.
About a decade ago, Montserrat Anguera, PhD, a biologist at the University of Pennsylvania, Philadelphia, began looking at the relationship of X-chromosome inactivation, which by definition involves Xist, and lupus.
Dr. Anguera hypothesized that imperfect X inactivation allowed for greater escape of genes associated with immunity and autoimmunity. Studying patients with lupus, Dr. Anguera found that the silencing process was abnormal, allowing more of these genes to escape the silenced X — including toll-like receptor 7 (TLR-7) and other genes implicated in the pathogenesis of lupus.
“If you get increased expression of certain genes from the [silenced] X, like TLR-7, it can result in autoimmune disease,” Dr. Anguera said. “So what we think is that in the lupus patients, because the silencing is impacted, you’re going to have more expression happening from the inactive X. And then in conjunction with the active X, that’s going to throw off the dosage [of autoimmunity-linked genes]. You’re changing the dosage of genes, and that’s what’s critical.”
Even among patients with lupus whose symptoms are well controlled with medication, “if you look at their T cells and B cells, they still have messed up X inactivation,” Dr. Anguera said. “The Xist RNA that’s supposed to be tethered to the inactive X in a fluffy cloud is not localized, and instead is dispersed all over the nucleus.”
Dr. Anguera pointed out that autoimmune diseases are complex and can result from a combination of factors. “You also have a host of hormonal and environmental contributors, such as previous viral infections,” she said. And of course men can also develop lupus, meaning that the X chromosome cannot explain everything.
Dr. Anguera said that, while the findings by the Stanford scientists do not explain the full pathogenesis of lupus and related diseases, they still support a strong role for Xist in sex-biased autoimmune diseases. “It’s sort of another take on it,” she said.
Is It the Proteins, the RNA, or Both?
The Stanford team points to the proteins recruited by Xist in the process of X-chromosome inactivation as the likely trigger of autoimmunity. However, a group of researchers at Johns Hopkins University in Baltimore, Maryland, made the case in a 2022 paper that Xist RNA itself was dangerous. They found that numerous short RNA sequences within the Xist molecule serve as ligands for TLR-7. And TLR-7 ligation causes plasmacytoid dendritic cells to overproduce type 1 interferon, a classic hallmark of lupus.
“Within rheumatology, the diseases that tend to be most female biased are the ones that are antibody positive and have this presence of upregulated interferon,” explained Brendan Antiochos, MD. “Lupus is an example of that. Sjögren’s syndrome is another. So there’s always been this quest to want to understand the mechanisms that explain why women would have more autoimmunity. And are there specific pathways which could contribute? One of the key pathways that’s been shown in humans and in mice to be important in lupus is toll-like receptor signaling.” Most convincingly, one recent study showed that people who have a gain-of-function mutation in their TLR-7 gene get a spontaneous form of lupus.
These findings led Erika Darrah, PhD, and her colleague Dr. Antiochos to begin looking more deeply into which RNAs could be triggering this signaling pathway. “We started to think: Well, there is this sex bias. Could it be that women have unique RNAs that could potentially act as triggers for TLR-7 signaling?” Dr. Darrah said.
Dr. Darrah and Dr. Antiochos looked at publicly available genetic data to identify sex-biased sources of self-RNA containing TLR-7 ligands. Xist, they found, was chock full of them. “Every time we analyzed that data, no matter what filter we applied, Xist kept popping out over and over again as the most highly female skewed RNA, the RNA most likely to contain these TLR-7 binding motifs,” Dr. Darrah said. “We started to formulate the hypothesis that Xist was actually promoting responses that were dangerous and pathogenic in lupus.”
That finding led the team to conduct in-vitro experiments that showed different fragments of Xist can activate TLR-7, resulting in higher interferon production. Finally, they looked at blood and kidney cells from women with lupus and found that higher Xist expression correlated with more interferon production, and higher disease activity. “The more Xist, the sicker people were,” Dr. Darrah said.
Xist’s Other Functions
Xist was first studied in the 1990s, and most research has centered on its primary role in X-chromosome inactivation. A research group led by Kathrin Plath, PhD, at the University of California, Los Angeles, has been occupied for years with untangling exactly how Xist does what it does. “It’s a very clever RNA, right? It can silence the whole chromosome,” Dr. Plath said in an interview.
In 2021, Dr. Plath and her colleagues established in detail how Xist executes silencing, setting down pairs of molecules in specific spots along the chromosome and building huge protein clouds around them. “We worked on learning where Xist binds and what proteins it binds, drilling down to understand how these proteins and the RNA are coming together.”
Dr. Plath has long suspected that Xist has other functions besides X inactivation, and she and her colleagues are starting to identify them. Early this year they published the surprising finding that Xist can regulate gene expression in autosomes, or non–sex-linked chromosomes, “which it might well also do in cancer cells and lymphocytes,” Dr. Plath said. “And now there is this new evidence of an autoimmune function,” she said. “It’s a super exciting time.”
The different hypotheses surrounding Xist’s role in sex-biased autoimmunity aren’t mutually exclusive, Dr. Plath said. “There’s a tremendous enrichment of proteins occurring” during X inactivation, she said, supporting the Stanford team’s hypothesis that proteins are triggering autoimmunity. As for the Johns Hopkins researchers’ understanding that Xist RNA itself is the trigger, “I’m totally open to that,” she said. “Why can’t it be an autoantigen?”
The other model in the field, Dr. Plath noted, is the one proposed by Dr. Anguera — “that there’s [gene] escape from X-inactivation — that females have more escape expression, and that Xist is more dispersed in the lymphocytes [of patients with lupus]. In fact, Xist becoming a little dispersed might make it a better antigen. So I do think everything is possible.”
The plethora of new findings related to autoimmunity has caused Dr. Plath to consider redirecting her lab’s focus toward more translational work, “because we are obviously good at studying Xist.” Among the mysteries Dr. Plath would like to solve is how some genes manage to escape the Xist cloud.
What is needed, she said, is collaboration. “Everyone will come up with different ideas. So I think it’s good to have more people look at things together. Then the field will achieve a breakthrough treatment.”
Female bias in autoimmune disease can be profound, with nine females developing lupus for every male affected, and nearly twice that ratio seen in Sjögren disease.
For years, researchers have worked to determine the reasons for sex-linked differences in immune response and autoimmunity, with environmental factors, sex hormones, and X-chromosome inactivation — the process by which a second X chromosome is silenced — all seen as having roles.
More recently, different groups of researchers have homed in on a long noncoding RNA fragment called X-inactive specific transcript, or Xist, as a potential driver of sex bias in autoimmune disease. Xist, which occurs in female mammals, has been known since the 1990s as the master regulator of X-chromosome inactivation, the process by which the second X chromosome is silenced, averting a fatal double dose of X-linked genes.
The inactivation process, which scientists liken to wrapping the extra X with a fluffy cloud of proteins, occurs early in embryonic development. After its initial work silencing the X, Xist is produced throughout the female’s life, allowing X inactivation to be maintained.
But is it possible that Xist, and the many dozens of proteins it recruits to keep that extra X chromosome silent, can also provoke autoimmunity? This is the question that several teams of researchers have been grappling with, resulting in provocative findings and opening exciting new avenues of discovery.
Xist Protein Complexes Make Male Mice Vulnerable to Lupus
In February, researchers Howard Chang, MD, PhD, and Diana Dou, PhD, of Stanford University in Stanford, California, made worldwide news when they published results from an experiment using male mice genetically engineered to carry a non-silencing form of Xist on one of their chromosomes.
Xist acts like a scaffold, recruiting multiple protein complexes to help it do its job. Dr. Dou explained in an interview that her team has been eyeing suspiciously for years the dozens of proteins Xist recruits in the process of X-chromosome inactivation, many of which are known autoantigens.
When the mice were injected with pristane, a chemical that induces lupus-like autoimmunity in mice, the Xist-producing males developed symptoms at a rate similar to that of females, while wild-type male mice did not.
By using a male model, the scientists could determine whether Xist could cause an increased vulnerability for autoimmunity absent the influence of female hormones and development. “Everything else about the animal is male,” Dr. Dou commented. “You just add the formation of the Xist ribonucleoprotein particles — Xist RNA plus the associating proteins — to male cells that would not ordinarily have these particles. Is just having the particles present in these animals sufficient to increase their autoimmunity? This is what our paper showed: That just having expression of Xist, the presence of these Xist [ribonucleoproteins], is enough in permissive genetic backgrounds to invoke higher incidence and severity of autoimmune disease development in our pristane-induced lupus model.”
The Stanford group sees the Xist protein complex, which they have studied extensively, as a key to understanding how Xist might provoke autoimmunity. Nonetheless, Dr. Dou said, “It’s important to note that there are other contributing factors, which is why not all females develop autoimmunity, and we had very different results in our autoimmune-resistant mouse strain compared to the more autoimmune-prone strain. Xist is a factor, but many factors are required to subvert the checkpoints in immune balance and allow the progression to full-blown autoimmunity.”
Faulty X Inactivation and Gene Escape
The understanding that Xist might be implicated in autoimmune disease — and explain some of its female bias — is not new.
About a decade ago, Montserrat Anguera, PhD, a biologist at the University of Pennsylvania, Philadelphia, began looking at the relationship of X-chromosome inactivation, which by definition involves Xist, and lupus.
Dr. Anguera hypothesized that imperfect X inactivation allowed for greater escape of genes associated with immunity and autoimmunity. Studying patients with lupus, Dr. Anguera found that the silencing process was abnormal, allowing more of these genes to escape the silenced X — including toll-like receptor 7 (TLR-7) and other genes implicated in the pathogenesis of lupus.
“If you get increased expression of certain genes from the [silenced] X, like TLR-7, it can result in autoimmune disease,” Dr. Anguera said. “So what we think is that in the lupus patients, because the silencing is impacted, you’re going to have more expression happening from the inactive X. And then in conjunction with the active X, that’s going to throw off the dosage [of autoimmunity-linked genes]. You’re changing the dosage of genes, and that’s what’s critical.”
Even among patients with lupus whose symptoms are well controlled with medication, “if you look at their T cells and B cells, they still have messed up X inactivation,” Dr. Anguera said. “The Xist RNA that’s supposed to be tethered to the inactive X in a fluffy cloud is not localized, and instead is dispersed all over the nucleus.”
Dr. Anguera pointed out that autoimmune diseases are complex and can result from a combination of factors. “You also have a host of hormonal and environmental contributors, such as previous viral infections,” she said. And of course men can also develop lupus, meaning that the X chromosome cannot explain everything.
Dr. Anguera said that, while the findings by the Stanford scientists do not explain the full pathogenesis of lupus and related diseases, they still support a strong role for Xist in sex-biased autoimmune diseases. “It’s sort of another take on it,” she said.
Is It the Proteins, the RNA, or Both?
The Stanford team points to the proteins recruited by Xist in the process of X-chromosome inactivation as the likely trigger of autoimmunity. However, a group of researchers at Johns Hopkins University in Baltimore, Maryland, made the case in a 2022 paper that Xist RNA itself was dangerous. They found that numerous short RNA sequences within the Xist molecule serve as ligands for TLR-7. And TLR-7 ligation causes plasmacytoid dendritic cells to overproduce type 1 interferon, a classic hallmark of lupus.
“Within rheumatology, the diseases that tend to be most female biased are the ones that are antibody positive and have this presence of upregulated interferon,” explained Brendan Antiochos, MD. “Lupus is an example of that. Sjögren’s syndrome is another. So there’s always been this quest to want to understand the mechanisms that explain why women would have more autoimmunity. And are there specific pathways which could contribute? One of the key pathways that’s been shown in humans and in mice to be important in lupus is toll-like receptor signaling.” Most convincingly, one recent study showed that people who have a gain-of-function mutation in their TLR-7 gene get a spontaneous form of lupus.
These findings led Erika Darrah, PhD, and her colleague Dr. Antiochos to begin looking more deeply into which RNAs could be triggering this signaling pathway. “We started to think: Well, there is this sex bias. Could it be that women have unique RNAs that could potentially act as triggers for TLR-7 signaling?” Dr. Darrah said.
Dr. Darrah and Dr. Antiochos looked at publicly available genetic data to identify sex-biased sources of self-RNA containing TLR-7 ligands. Xist, they found, was chock full of them. “Every time we analyzed that data, no matter what filter we applied, Xist kept popping out over and over again as the most highly female skewed RNA, the RNA most likely to contain these TLR-7 binding motifs,” Dr. Darrah said. “We started to formulate the hypothesis that Xist was actually promoting responses that were dangerous and pathogenic in lupus.”
That finding led the team to conduct in-vitro experiments that showed different fragments of Xist can activate TLR-7, resulting in higher interferon production. Finally, they looked at blood and kidney cells from women with lupus and found that higher Xist expression correlated with more interferon production, and higher disease activity. “The more Xist, the sicker people were,” Dr. Darrah said.
Xist’s Other Functions
Xist was first studied in the 1990s, and most research has centered on its primary role in X-chromosome inactivation. A research group led by Kathrin Plath, PhD, at the University of California, Los Angeles, has been occupied for years with untangling exactly how Xist does what it does. “It’s a very clever RNA, right? It can silence the whole chromosome,” Dr. Plath said in an interview.
In 2021, Dr. Plath and her colleagues established in detail how Xist executes silencing, setting down pairs of molecules in specific spots along the chromosome and building huge protein clouds around them. “We worked on learning where Xist binds and what proteins it binds, drilling down to understand how these proteins and the RNA are coming together.”
Dr. Plath has long suspected that Xist has other functions besides X inactivation, and she and her colleagues are starting to identify them. Early this year they published the surprising finding that Xist can regulate gene expression in autosomes, or non–sex-linked chromosomes, “which it might well also do in cancer cells and lymphocytes,” Dr. Plath said. “And now there is this new evidence of an autoimmune function,” she said. “It’s a super exciting time.”
The different hypotheses surrounding Xist’s role in sex-biased autoimmunity aren’t mutually exclusive, Dr. Plath said. “There’s a tremendous enrichment of proteins occurring” during X inactivation, she said, supporting the Stanford team’s hypothesis that proteins are triggering autoimmunity. As for the Johns Hopkins researchers’ understanding that Xist RNA itself is the trigger, “I’m totally open to that,” she said. “Why can’t it be an autoantigen?”
The other model in the field, Dr. Plath noted, is the one proposed by Dr. Anguera — “that there’s [gene] escape from X-inactivation — that females have more escape expression, and that Xist is more dispersed in the lymphocytes [of patients with lupus]. In fact, Xist becoming a little dispersed might make it a better antigen. So I do think everything is possible.”
The plethora of new findings related to autoimmunity has caused Dr. Plath to consider redirecting her lab’s focus toward more translational work, “because we are obviously good at studying Xist.” Among the mysteries Dr. Plath would like to solve is how some genes manage to escape the Xist cloud.
What is needed, she said, is collaboration. “Everyone will come up with different ideas. So I think it’s good to have more people look at things together. Then the field will achieve a breakthrough treatment.”
Democratic Lawmakers Press Pfizer on Chemotherapy Drug Shortages
In a statement about their February 21 action, the legislators, led by Rep. Jamie Raskin (D-Md.), the committee’s ranking minority member, described their work as a follow up to an earlier investigation into price hikes of generic drugs. While the committee members queried Pfizer over the three oncology medications only, they also sent letters to drugmakers Teva and Sandoz with respect to shortages in other drug classes.
A representative for Pfizer confirmed to MDedge Oncology that the company had received the representatives’ letter but said “we have no further details to provide at this time.”
What is the basis for concern?
All three generic chemotherapy drugs are mainstay treatments used across a broad array of cancers. Though shortages have been reported for several years, they became especially acute after December 2022, when an inspection by the US Food and Drug Administration (FDA) led to regulatory action against an Indian manufacturer, Intas, that produced up to half of the platinum-based therapies supplied globally. The National Comprehensive Cancer Care Network reported in October 2023 that more than 90% of its member centers were struggling to maintain adequate supplies of carboplatin, and 70% had trouble obtaining cisplatin, while the American Society of Clinical Oncology published clinical guidance on alternative treatment strategies.
What has the government done in response to the recent shortages?
The White House and the FDA announced in September that they were working with several manufacturers to help increase supplies of the platinum-based chemotherapies and of methotrexate, and taking measures that included relaxing rules on imports. Recent guidance under a pandemic-era federal law, the 2020 CARES Act, strengthened manufacturer reporting requirements related to drug shortages, and other measures have been proposed. While federal regulators have many tools with which to address drug shortages, they cannot legally oblige a manufacturer to increase production of a drug.
What can the lawmakers expect to achieve with their letter?
By pressuring Pfizer publicly, the lawmakers may be able to nudge the company to take measures to assure more consistent supplies of the three drugs. The lawmakers also said they hoped to glean from Pfizer more insight into the root causes of the shortages and potential remedies. They noted that, in a May 2023 letter by Pfizer to customers, the company had warned of depleted and limited supplies of the three drugs and said it was “working diligently” to increase output. However, the lawmakers wrote, “the root cause is not yet resolved and carboplatin, cisplatin, and methotrexate continue to experience residual delays.”
Why did the committee target Pfizer specifically?
Pfizer and its subsidiaries are among the major manufacturers of the three generic chemotherapy agents mentioned in the letter. The legislators noted that “pharmaceutical companies may not be motivated to produce generic drugs like carboplatin, cisplatin, and methotrexate, because they are not as lucrative as producing patented brand name drugs,” and that “as a principal supplier of carboplatin, cisplatin, and methotrexate, it is critical that Pfizer continues to increase production of these life-sustaining cancer medications, even amidst potential lower profitability.”
The committee members also made reference to news reports of price-gouging with these medications, as smaller hospitals or oncology centers are forced to turn to unscrupulous third-party suppliers.
What is being demanded of Pfizer?
Pfizer was given until March 6 to respond, in writing and in a briefing with committee staff, to a six questions. These queries concern what specific steps the company has taken to increase supplies of the three generic oncology drugs, what Pfizer is doing to help avert price-gouging, whether further oncology drug shortages are anticipated, and how the company is working with the FDA on the matter.
In a statement about their February 21 action, the legislators, led by Rep. Jamie Raskin (D-Md.), the committee’s ranking minority member, described their work as a follow up to an earlier investigation into price hikes of generic drugs. While the committee members queried Pfizer over the three oncology medications only, they also sent letters to drugmakers Teva and Sandoz with respect to shortages in other drug classes.
A representative for Pfizer confirmed to MDedge Oncology that the company had received the representatives’ letter but said “we have no further details to provide at this time.”
What is the basis for concern?
All three generic chemotherapy drugs are mainstay treatments used across a broad array of cancers. Though shortages have been reported for several years, they became especially acute after December 2022, when an inspection by the US Food and Drug Administration (FDA) led to regulatory action against an Indian manufacturer, Intas, that produced up to half of the platinum-based therapies supplied globally. The National Comprehensive Cancer Care Network reported in October 2023 that more than 90% of its member centers were struggling to maintain adequate supplies of carboplatin, and 70% had trouble obtaining cisplatin, while the American Society of Clinical Oncology published clinical guidance on alternative treatment strategies.
What has the government done in response to the recent shortages?
The White House and the FDA announced in September that they were working with several manufacturers to help increase supplies of the platinum-based chemotherapies and of methotrexate, and taking measures that included relaxing rules on imports. Recent guidance under a pandemic-era federal law, the 2020 CARES Act, strengthened manufacturer reporting requirements related to drug shortages, and other measures have been proposed. While federal regulators have many tools with which to address drug shortages, they cannot legally oblige a manufacturer to increase production of a drug.
What can the lawmakers expect to achieve with their letter?
By pressuring Pfizer publicly, the lawmakers may be able to nudge the company to take measures to assure more consistent supplies of the three drugs. The lawmakers also said they hoped to glean from Pfizer more insight into the root causes of the shortages and potential remedies. They noted that, in a May 2023 letter by Pfizer to customers, the company had warned of depleted and limited supplies of the three drugs and said it was “working diligently” to increase output. However, the lawmakers wrote, “the root cause is not yet resolved and carboplatin, cisplatin, and methotrexate continue to experience residual delays.”
Why did the committee target Pfizer specifically?
Pfizer and its subsidiaries are among the major manufacturers of the three generic chemotherapy agents mentioned in the letter. The legislators noted that “pharmaceutical companies may not be motivated to produce generic drugs like carboplatin, cisplatin, and methotrexate, because they are not as lucrative as producing patented brand name drugs,” and that “as a principal supplier of carboplatin, cisplatin, and methotrexate, it is critical that Pfizer continues to increase production of these life-sustaining cancer medications, even amidst potential lower profitability.”
The committee members also made reference to news reports of price-gouging with these medications, as smaller hospitals or oncology centers are forced to turn to unscrupulous third-party suppliers.
What is being demanded of Pfizer?
Pfizer was given until March 6 to respond, in writing and in a briefing with committee staff, to a six questions. These queries concern what specific steps the company has taken to increase supplies of the three generic oncology drugs, what Pfizer is doing to help avert price-gouging, whether further oncology drug shortages are anticipated, and how the company is working with the FDA on the matter.
In a statement about their February 21 action, the legislators, led by Rep. Jamie Raskin (D-Md.), the committee’s ranking minority member, described their work as a follow up to an earlier investigation into price hikes of generic drugs. While the committee members queried Pfizer over the three oncology medications only, they also sent letters to drugmakers Teva and Sandoz with respect to shortages in other drug classes.
A representative for Pfizer confirmed to MDedge Oncology that the company had received the representatives’ letter but said “we have no further details to provide at this time.”
What is the basis for concern?
All three generic chemotherapy drugs are mainstay treatments used across a broad array of cancers. Though shortages have been reported for several years, they became especially acute after December 2022, when an inspection by the US Food and Drug Administration (FDA) led to regulatory action against an Indian manufacturer, Intas, that produced up to half of the platinum-based therapies supplied globally. The National Comprehensive Cancer Care Network reported in October 2023 that more than 90% of its member centers were struggling to maintain adequate supplies of carboplatin, and 70% had trouble obtaining cisplatin, while the American Society of Clinical Oncology published clinical guidance on alternative treatment strategies.
What has the government done in response to the recent shortages?
The White House and the FDA announced in September that they were working with several manufacturers to help increase supplies of the platinum-based chemotherapies and of methotrexate, and taking measures that included relaxing rules on imports. Recent guidance under a pandemic-era federal law, the 2020 CARES Act, strengthened manufacturer reporting requirements related to drug shortages, and other measures have been proposed. While federal regulators have many tools with which to address drug shortages, they cannot legally oblige a manufacturer to increase production of a drug.
What can the lawmakers expect to achieve with their letter?
By pressuring Pfizer publicly, the lawmakers may be able to nudge the company to take measures to assure more consistent supplies of the three drugs. The lawmakers also said they hoped to glean from Pfizer more insight into the root causes of the shortages and potential remedies. They noted that, in a May 2023 letter by Pfizer to customers, the company had warned of depleted and limited supplies of the three drugs and said it was “working diligently” to increase output. However, the lawmakers wrote, “the root cause is not yet resolved and carboplatin, cisplatin, and methotrexate continue to experience residual delays.”
Why did the committee target Pfizer specifically?
Pfizer and its subsidiaries are among the major manufacturers of the three generic chemotherapy agents mentioned in the letter. The legislators noted that “pharmaceutical companies may not be motivated to produce generic drugs like carboplatin, cisplatin, and methotrexate, because they are not as lucrative as producing patented brand name drugs,” and that “as a principal supplier of carboplatin, cisplatin, and methotrexate, it is critical that Pfizer continues to increase production of these life-sustaining cancer medications, even amidst potential lower profitability.”
The committee members also made reference to news reports of price-gouging with these medications, as smaller hospitals or oncology centers are forced to turn to unscrupulous third-party suppliers.
What is being demanded of Pfizer?
Pfizer was given until March 6 to respond, in writing and in a briefing with committee staff, to a six questions. These queries concern what specific steps the company has taken to increase supplies of the three generic oncology drugs, what Pfizer is doing to help avert price-gouging, whether further oncology drug shortages are anticipated, and how the company is working with the FDA on the matter.
Circulating Tumor Cells Can Predict Progression in Stage 3 NSCLC
Circulating tumor cells (CTCs), the cells shed from a solid tumor into the bloodstream, may help doctors avoid having to do repeat needle biopsies on patients with unresectable non–small cell lung cancer.
Challenges to using CTCs clinically are that they are not abundant in the blood and have been difficult to isolate in patients with this type of cancer with commercially available assays.
In their paper, the authors show that an experimental nanotechnology can effectively isolate and measure CTCs in patients with stage 3 NSCLC. They also found that a precipitous drop in CTCs during chemoradiation treatment predicted significantly longer progression-free survival in those patients.
Study Results and Methods
For their research, study coauthors Shruti Jolly, MD, and Sunitha Nagrath, PhD, used a novel graphene oxide technology called the GO chip, developed more than a decade ago by Dr. Nagrath and her colleagues, to isolate CTCs from patients with stage 3 NSCLC. While a different technology, which is approved by the US Food and Drug Administration (FDA), uses a single antibody to pick up CTCs, the GO chip uses a cocktail of three antibodies to CTC proteins, making it more sensitive.
The 26 patients in the study (mean age 67, 27% female) all received radiation treatment for 6 weeks, plus weekly carboplatin and paclitaxel chemotherapy. Sixteen of the patients afterward went on to have immunotherapy with durvalumab. Blood was drawn at six fixed time points: before treatment, and at weeks 1, 4, 10, 18, and 30. CTCs were measured and analyzed with every draw.
Previous studies showed that absolute number of CTCs did not correlate with either tumor volume or progression-free survival in NSCLC.
Dr. Jolly and Dr. Nagrath sought to measure change in CTCs from baseline for each patient, having the patient serve as his or her own control. They found that patients whose individual CTC counts dropped by 75% or more between pretreatment and week 4 of chemoradiation saw a mean 21 months of progression-free survival compared with 7 months for patients whose CTCs dropped by less than 75% in the same period (P = .0076).
Dr. Jolly and Dr. Nagrath also aimed to determine, as an exploratory outcome of their study, whether other information collected from the CTCs could predict response to treatment with durvalumab immunotherapy. They found that having more than 50% of CTCs positive for the protein PD-L1 correlated to shorter progression-free survival among the 16 patients receiving durvalumab (P = .04).
“Every person’s tumor is unique in terms of its response to treatment,” said Dr. Jolly, a radiation oncologist and professor and associate chair of community practices in the Department of Radiation Oncology at the University of Michigan, Ann Arbor.
“Two people with a three-centimeter lung tumor will not necessarily shed the same amount of tumor cells into circulation. CTCs are reflective of disease burden; however, this is not related to the absolute numbers. That’s why we decided to use individualized baselines and look at the percentage of decrease,” she said.
Dr. Nagrath, professor of chemical and biomedical engineering at the University of Michigan, noted, in the same interview, that the findings argue for CTCs as a biomarker in stage 3 NSCLC.
“A lot of researchers who do lung cancer studies struggle with isolating lung cancer CTCs,” Dr. Nagrath said. “We showed, with repeated blood draws during treatment, what is changing at a molecular level and that you can see it with a simple blood draw. It also gives the proof of concept that if these cells are present, this is a good way to monitor and see if a treatment is working, even early in the treatment.” Moreover, she added, “many studies in lung cancer are in stage 4.”
Our study is unique as it followed patients with locally advanced tumors from their being treatment naive to all the way through immunotherapy,” she continued.
The University of Michigan has a patent on the GO chip technology, but thus far no company has made efforts to license it and submit it for approval. While “liquid biopsy” is an important emerging concept in lung cancer, there is little consensus yet as to which blood biomarkers — whether CTCs, circulating tumor DNA (ctDNA), or extracellular vesicles (EVs) — are most clinically relevant, Dr. Nagrath said.
The study’s small size is one of its weaknesses, according to the authors.
Findings are ‘Particularly Intriguing’
Majid Ebrahimi Warkiani, PhD, who was not involved in the study, described the new findings as “particularly intriguing [and] highlighting the efficacy of liquid biopsy using CTCs for predicting treatment outcomes.”
A challenge within the realm of CTCs lies in the community’s ongoing struggle to define and classify these cells accurately, Dr. Warkiani said in an interview.
“While surface protein markers offer valuable insights, emerging layers of analysis, such as metabolomics, are increasingly entering the scene to bolster the identification of putative cancer cells, alongside molecular tests like fluorescence in situ hybridization (FISH),” said Dr. Warkiani of the University of Technology Sydney in Australia. “The amalgamation of these approaches simultaneously presents a significant challenge, particularly in terms of standardization for patient care, unlike ctDNA, which faces fewer bottlenecks.
“The robustness of the research in this study is commendable. However, further clinical testing and randomized trials are imperative,” Dr. Warkiani continued. “Companies like Epic Sciences are actively engaged in advancing research and standardization in this field.”
The study by Dr. Jolly and Dr. Nagrath was funded by the National Institutes of Health. None of the study authors reported financial conflicts of interest. Dr. Warkiani reported no conflicts of interest related to his comment.
Circulating tumor cells (CTCs), the cells shed from a solid tumor into the bloodstream, may help doctors avoid having to do repeat needle biopsies on patients with unresectable non–small cell lung cancer.
Challenges to using CTCs clinically are that they are not abundant in the blood and have been difficult to isolate in patients with this type of cancer with commercially available assays.
In their paper, the authors show that an experimental nanotechnology can effectively isolate and measure CTCs in patients with stage 3 NSCLC. They also found that a precipitous drop in CTCs during chemoradiation treatment predicted significantly longer progression-free survival in those patients.
Study Results and Methods
For their research, study coauthors Shruti Jolly, MD, and Sunitha Nagrath, PhD, used a novel graphene oxide technology called the GO chip, developed more than a decade ago by Dr. Nagrath and her colleagues, to isolate CTCs from patients with stage 3 NSCLC. While a different technology, which is approved by the US Food and Drug Administration (FDA), uses a single antibody to pick up CTCs, the GO chip uses a cocktail of three antibodies to CTC proteins, making it more sensitive.
The 26 patients in the study (mean age 67, 27% female) all received radiation treatment for 6 weeks, plus weekly carboplatin and paclitaxel chemotherapy. Sixteen of the patients afterward went on to have immunotherapy with durvalumab. Blood was drawn at six fixed time points: before treatment, and at weeks 1, 4, 10, 18, and 30. CTCs were measured and analyzed with every draw.
Previous studies showed that absolute number of CTCs did not correlate with either tumor volume or progression-free survival in NSCLC.
Dr. Jolly and Dr. Nagrath sought to measure change in CTCs from baseline for each patient, having the patient serve as his or her own control. They found that patients whose individual CTC counts dropped by 75% or more between pretreatment and week 4 of chemoradiation saw a mean 21 months of progression-free survival compared with 7 months for patients whose CTCs dropped by less than 75% in the same period (P = .0076).
Dr. Jolly and Dr. Nagrath also aimed to determine, as an exploratory outcome of their study, whether other information collected from the CTCs could predict response to treatment with durvalumab immunotherapy. They found that having more than 50% of CTCs positive for the protein PD-L1 correlated to shorter progression-free survival among the 16 patients receiving durvalumab (P = .04).
“Every person’s tumor is unique in terms of its response to treatment,” said Dr. Jolly, a radiation oncologist and professor and associate chair of community practices in the Department of Radiation Oncology at the University of Michigan, Ann Arbor.
“Two people with a three-centimeter lung tumor will not necessarily shed the same amount of tumor cells into circulation. CTCs are reflective of disease burden; however, this is not related to the absolute numbers. That’s why we decided to use individualized baselines and look at the percentage of decrease,” she said.
Dr. Nagrath, professor of chemical and biomedical engineering at the University of Michigan, noted, in the same interview, that the findings argue for CTCs as a biomarker in stage 3 NSCLC.
“A lot of researchers who do lung cancer studies struggle with isolating lung cancer CTCs,” Dr. Nagrath said. “We showed, with repeated blood draws during treatment, what is changing at a molecular level and that you can see it with a simple blood draw. It also gives the proof of concept that if these cells are present, this is a good way to monitor and see if a treatment is working, even early in the treatment.” Moreover, she added, “many studies in lung cancer are in stage 4.”
Our study is unique as it followed patients with locally advanced tumors from their being treatment naive to all the way through immunotherapy,” she continued.
The University of Michigan has a patent on the GO chip technology, but thus far no company has made efforts to license it and submit it for approval. While “liquid biopsy” is an important emerging concept in lung cancer, there is little consensus yet as to which blood biomarkers — whether CTCs, circulating tumor DNA (ctDNA), or extracellular vesicles (EVs) — are most clinically relevant, Dr. Nagrath said.
The study’s small size is one of its weaknesses, according to the authors.
Findings are ‘Particularly Intriguing’
Majid Ebrahimi Warkiani, PhD, who was not involved in the study, described the new findings as “particularly intriguing [and] highlighting the efficacy of liquid biopsy using CTCs for predicting treatment outcomes.”
A challenge within the realm of CTCs lies in the community’s ongoing struggle to define and classify these cells accurately, Dr. Warkiani said in an interview.
“While surface protein markers offer valuable insights, emerging layers of analysis, such as metabolomics, are increasingly entering the scene to bolster the identification of putative cancer cells, alongside molecular tests like fluorescence in situ hybridization (FISH),” said Dr. Warkiani of the University of Technology Sydney in Australia. “The amalgamation of these approaches simultaneously presents a significant challenge, particularly in terms of standardization for patient care, unlike ctDNA, which faces fewer bottlenecks.
“The robustness of the research in this study is commendable. However, further clinical testing and randomized trials are imperative,” Dr. Warkiani continued. “Companies like Epic Sciences are actively engaged in advancing research and standardization in this field.”
The study by Dr. Jolly and Dr. Nagrath was funded by the National Institutes of Health. None of the study authors reported financial conflicts of interest. Dr. Warkiani reported no conflicts of interest related to his comment.
Circulating tumor cells (CTCs), the cells shed from a solid tumor into the bloodstream, may help doctors avoid having to do repeat needle biopsies on patients with unresectable non–small cell lung cancer.
Challenges to using CTCs clinically are that they are not abundant in the blood and have been difficult to isolate in patients with this type of cancer with commercially available assays.
In their paper, the authors show that an experimental nanotechnology can effectively isolate and measure CTCs in patients with stage 3 NSCLC. They also found that a precipitous drop in CTCs during chemoradiation treatment predicted significantly longer progression-free survival in those patients.
Study Results and Methods
For their research, study coauthors Shruti Jolly, MD, and Sunitha Nagrath, PhD, used a novel graphene oxide technology called the GO chip, developed more than a decade ago by Dr. Nagrath and her colleagues, to isolate CTCs from patients with stage 3 NSCLC. While a different technology, which is approved by the US Food and Drug Administration (FDA), uses a single antibody to pick up CTCs, the GO chip uses a cocktail of three antibodies to CTC proteins, making it more sensitive.
The 26 patients in the study (mean age 67, 27% female) all received radiation treatment for 6 weeks, plus weekly carboplatin and paclitaxel chemotherapy. Sixteen of the patients afterward went on to have immunotherapy with durvalumab. Blood was drawn at six fixed time points: before treatment, and at weeks 1, 4, 10, 18, and 30. CTCs were measured and analyzed with every draw.
Previous studies showed that absolute number of CTCs did not correlate with either tumor volume or progression-free survival in NSCLC.
Dr. Jolly and Dr. Nagrath sought to measure change in CTCs from baseline for each patient, having the patient serve as his or her own control. They found that patients whose individual CTC counts dropped by 75% or more between pretreatment and week 4 of chemoradiation saw a mean 21 months of progression-free survival compared with 7 months for patients whose CTCs dropped by less than 75% in the same period (P = .0076).
Dr. Jolly and Dr. Nagrath also aimed to determine, as an exploratory outcome of their study, whether other information collected from the CTCs could predict response to treatment with durvalumab immunotherapy. They found that having more than 50% of CTCs positive for the protein PD-L1 correlated to shorter progression-free survival among the 16 patients receiving durvalumab (P = .04).
“Every person’s tumor is unique in terms of its response to treatment,” said Dr. Jolly, a radiation oncologist and professor and associate chair of community practices in the Department of Radiation Oncology at the University of Michigan, Ann Arbor.
“Two people with a three-centimeter lung tumor will not necessarily shed the same amount of tumor cells into circulation. CTCs are reflective of disease burden; however, this is not related to the absolute numbers. That’s why we decided to use individualized baselines and look at the percentage of decrease,” she said.
Dr. Nagrath, professor of chemical and biomedical engineering at the University of Michigan, noted, in the same interview, that the findings argue for CTCs as a biomarker in stage 3 NSCLC.
“A lot of researchers who do lung cancer studies struggle with isolating lung cancer CTCs,” Dr. Nagrath said. “We showed, with repeated blood draws during treatment, what is changing at a molecular level and that you can see it with a simple blood draw. It also gives the proof of concept that if these cells are present, this is a good way to monitor and see if a treatment is working, even early in the treatment.” Moreover, she added, “many studies in lung cancer are in stage 4.”
Our study is unique as it followed patients with locally advanced tumors from their being treatment naive to all the way through immunotherapy,” she continued.
The University of Michigan has a patent on the GO chip technology, but thus far no company has made efforts to license it and submit it for approval. While “liquid biopsy” is an important emerging concept in lung cancer, there is little consensus yet as to which blood biomarkers — whether CTCs, circulating tumor DNA (ctDNA), or extracellular vesicles (EVs) — are most clinically relevant, Dr. Nagrath said.
The study’s small size is one of its weaknesses, according to the authors.
Findings are ‘Particularly Intriguing’
Majid Ebrahimi Warkiani, PhD, who was not involved in the study, described the new findings as “particularly intriguing [and] highlighting the efficacy of liquid biopsy using CTCs for predicting treatment outcomes.”
A challenge within the realm of CTCs lies in the community’s ongoing struggle to define and classify these cells accurately, Dr. Warkiani said in an interview.
“While surface protein markers offer valuable insights, emerging layers of analysis, such as metabolomics, are increasingly entering the scene to bolster the identification of putative cancer cells, alongside molecular tests like fluorescence in situ hybridization (FISH),” said Dr. Warkiani of the University of Technology Sydney in Australia. “The amalgamation of these approaches simultaneously presents a significant challenge, particularly in terms of standardization for patient care, unlike ctDNA, which faces fewer bottlenecks.
“The robustness of the research in this study is commendable. However, further clinical testing and randomized trials are imperative,” Dr. Warkiani continued. “Companies like Epic Sciences are actively engaged in advancing research and standardization in this field.”
The study by Dr. Jolly and Dr. Nagrath was funded by the National Institutes of Health. None of the study authors reported financial conflicts of interest. Dr. Warkiani reported no conflicts of interest related to his comment.
FROM CELL REPORTS
Functional Outcomes in Localized Prostate Cancer: Treatment Choice, Time, Prognosis All Matter
New research published Jan. 23 in JAMA parses functional outcome results from a population-based study of men diagnosed with localized prostate cancer. For their research, Bashir Al Hussein Al Awamlh, MD, of Vanderbilt University in Nashville, Tennessee, and his colleagues, looked at sexual function, urinary health, bowel function, hormonal function, and other outcomes in this cohort at 10 years’ follow-up.
Among 2455 patients for whom 10-year data were available, 1877 were deemed at baseline to have a favorable prognosis (defined as cT1-cT2bN0M0, prostate-specific antigen level less than 20 ng/mL, and grade group 1-2) and 568 had unfavorable-prognosis prostate cancer (defined as cT2cN0M0, prostate-specific antigen level of 20-50 ng/mL, or grade group 3-5). Follow-up data were collected by questionnaire through February 1, 2022. The men in the study were all younger than 80 years, and three-quarters of them were White.
At 10 years, outcomes differed based on the amount of time that had passed since diagnosis (they found different results at 3 and 5 year follow up, for example) and which treatment a patient received.
Among men with favorable prognoses at diagnosis, 20% underwent active surveillance for at least 1 year, while 56% received radical prostatectomy, 19% had external beam radiotherapy (EBRT) without ADT, and 5% had brachytherapy. Nearly a third of men originally opting for surveillance went on to undergo a therapeutic intervention by 10 years.
Dr. Al Hussein Al Awamlh and his colleagues found that while 3- and 5-year follow-up studies in this cohort had shown declines in sexual function among men who underwent surgery compared with those who had radiation or active surveillance, by 10 years those differences had faded, with no clinically meaningful differences in sexual function scores between the surgery and surveillance groups. In an interview, Dr. Al Hussein Al Awamlh said that this finding likely reflected mainly age-related declines in function across the study population — though it could also reflect declines after converting from surveillance to surgery or gradual decline with radiation treatment, he acknowledged.
Men with favorable prognoses at baseline who underwent surgery saw significantly worse urinary incontinence at 10 years compared with those started on radiotherapy or active surveillance. And EBRT was associated with fewer incontinence issues compared with active surveillance.
Among the group of men with an unfavorable prognosis at baseline, 64% of whom underwent radical prostatectomy and 36% EBRT with ADT, surgery was associated with worse urinary incontinence but not worse sexual function throughout 10 years of follow up, compared to radiotherapy with androgen deprivation therapy.
Radiation-treated patients with unfavorable prognoses, meanwhile, saw significantly worse bowel function and hormone function at 10 years compared with patients who had undergone surgery.
Dr. Al Hussein Al Awamlh said that a strength of this study was that “we had enough patients to stratify functional outcomes based on disease prognosis.” Another key finding was that some of the outcomes changed over time. “For example, among the patients with unfavorable prognoses, at 10-year follow-up there was slightly worse bowel and hormone function seen associated with radiation with ADT compared with surgery,” he said — something not seen at earlier follow-up points.
The findings may help offer a more nuanced way to counsel patients, Dr. Al Hussein Al Awamlh noted. For example, the side effects associated with sexual function “are not as relevant for those with unfavorable disease,” he said.
While current prostate cancer guidelines do address quality of life in shared decision-making, he said, “hopefully this data may provide more insight on that.” For patients with favorable prognosis, the findings reinforce that “active surveillance is a great option because it avoids the effects associated with those other treatments.”
Ultimately, Dr. Al Hussein Al Awamlh said, “this is a patient preference issue. It’s important for patients to understand how different functions are affected and to decide what is better for them — what they can live with and what they cannot, provided all the options are oncologically safe.”
The study authors disclosed as limitations of their study its observational design, the potential for response bias among study participants, and small numbers for some of the measured outcomes.
In an interview, urologist Mark S. Litwin, MD, of the University of California Los Angeles, characterized the study as “a well-conducted very-long-term longitudinal cohort that tracked men long past the initial diagnosis and treatment. That empowered the Vanderbilt team to find differences in quality of life many years later and compare them to other older men who had not received treatment.”
The new findings, Dr. Litwin said, “are critical in showing that most men with prostate cancer do not die from it; hence, the quality-of-life effects end up being the key issues for decision-making.”
Dr. Al Hussein Al Awamlh and colleagues’ study was funded by grants from the National Institutes of Health, the Agency for Healthcare Research and Quality, and the Patient-Centered Outcomes Research Institute. Several coauthors disclosed funding from pharmaceutical and/or device manufacturers. Dr. Litwin disclosed no conflicts of interest related to his comment.
New research published Jan. 23 in JAMA parses functional outcome results from a population-based study of men diagnosed with localized prostate cancer. For their research, Bashir Al Hussein Al Awamlh, MD, of Vanderbilt University in Nashville, Tennessee, and his colleagues, looked at sexual function, urinary health, bowel function, hormonal function, and other outcomes in this cohort at 10 years’ follow-up.
Among 2455 patients for whom 10-year data were available, 1877 were deemed at baseline to have a favorable prognosis (defined as cT1-cT2bN0M0, prostate-specific antigen level less than 20 ng/mL, and grade group 1-2) and 568 had unfavorable-prognosis prostate cancer (defined as cT2cN0M0, prostate-specific antigen level of 20-50 ng/mL, or grade group 3-5). Follow-up data were collected by questionnaire through February 1, 2022. The men in the study were all younger than 80 years, and three-quarters of them were White.
At 10 years, outcomes differed based on the amount of time that had passed since diagnosis (they found different results at 3 and 5 year follow up, for example) and which treatment a patient received.
Among men with favorable prognoses at diagnosis, 20% underwent active surveillance for at least 1 year, while 56% received radical prostatectomy, 19% had external beam radiotherapy (EBRT) without ADT, and 5% had brachytherapy. Nearly a third of men originally opting for surveillance went on to undergo a therapeutic intervention by 10 years.
Dr. Al Hussein Al Awamlh and his colleagues found that while 3- and 5-year follow-up studies in this cohort had shown declines in sexual function among men who underwent surgery compared with those who had radiation or active surveillance, by 10 years those differences had faded, with no clinically meaningful differences in sexual function scores between the surgery and surveillance groups. In an interview, Dr. Al Hussein Al Awamlh said that this finding likely reflected mainly age-related declines in function across the study population — though it could also reflect declines after converting from surveillance to surgery or gradual decline with radiation treatment, he acknowledged.
Men with favorable prognoses at baseline who underwent surgery saw significantly worse urinary incontinence at 10 years compared with those started on radiotherapy or active surveillance. And EBRT was associated with fewer incontinence issues compared with active surveillance.
Among the group of men with an unfavorable prognosis at baseline, 64% of whom underwent radical prostatectomy and 36% EBRT with ADT, surgery was associated with worse urinary incontinence but not worse sexual function throughout 10 years of follow up, compared to radiotherapy with androgen deprivation therapy.
Radiation-treated patients with unfavorable prognoses, meanwhile, saw significantly worse bowel function and hormone function at 10 years compared with patients who had undergone surgery.
Dr. Al Hussein Al Awamlh said that a strength of this study was that “we had enough patients to stratify functional outcomes based on disease prognosis.” Another key finding was that some of the outcomes changed over time. “For example, among the patients with unfavorable prognoses, at 10-year follow-up there was slightly worse bowel and hormone function seen associated with radiation with ADT compared with surgery,” he said — something not seen at earlier follow-up points.
The findings may help offer a more nuanced way to counsel patients, Dr. Al Hussein Al Awamlh noted. For example, the side effects associated with sexual function “are not as relevant for those with unfavorable disease,” he said.
While current prostate cancer guidelines do address quality of life in shared decision-making, he said, “hopefully this data may provide more insight on that.” For patients with favorable prognosis, the findings reinforce that “active surveillance is a great option because it avoids the effects associated with those other treatments.”
Ultimately, Dr. Al Hussein Al Awamlh said, “this is a patient preference issue. It’s important for patients to understand how different functions are affected and to decide what is better for them — what they can live with and what they cannot, provided all the options are oncologically safe.”
The study authors disclosed as limitations of their study its observational design, the potential for response bias among study participants, and small numbers for some of the measured outcomes.
In an interview, urologist Mark S. Litwin, MD, of the University of California Los Angeles, characterized the study as “a well-conducted very-long-term longitudinal cohort that tracked men long past the initial diagnosis and treatment. That empowered the Vanderbilt team to find differences in quality of life many years later and compare them to other older men who had not received treatment.”
The new findings, Dr. Litwin said, “are critical in showing that most men with prostate cancer do not die from it; hence, the quality-of-life effects end up being the key issues for decision-making.”
Dr. Al Hussein Al Awamlh and colleagues’ study was funded by grants from the National Institutes of Health, the Agency for Healthcare Research and Quality, and the Patient-Centered Outcomes Research Institute. Several coauthors disclosed funding from pharmaceutical and/or device manufacturers. Dr. Litwin disclosed no conflicts of interest related to his comment.
New research published Jan. 23 in JAMA parses functional outcome results from a population-based study of men diagnosed with localized prostate cancer. For their research, Bashir Al Hussein Al Awamlh, MD, of Vanderbilt University in Nashville, Tennessee, and his colleagues, looked at sexual function, urinary health, bowel function, hormonal function, and other outcomes in this cohort at 10 years’ follow-up.
Among 2455 patients for whom 10-year data were available, 1877 were deemed at baseline to have a favorable prognosis (defined as cT1-cT2bN0M0, prostate-specific antigen level less than 20 ng/mL, and grade group 1-2) and 568 had unfavorable-prognosis prostate cancer (defined as cT2cN0M0, prostate-specific antigen level of 20-50 ng/mL, or grade group 3-5). Follow-up data were collected by questionnaire through February 1, 2022. The men in the study were all younger than 80 years, and three-quarters of them were White.
At 10 years, outcomes differed based on the amount of time that had passed since diagnosis (they found different results at 3 and 5 year follow up, for example) and which treatment a patient received.
Among men with favorable prognoses at diagnosis, 20% underwent active surveillance for at least 1 year, while 56% received radical prostatectomy, 19% had external beam radiotherapy (EBRT) without ADT, and 5% had brachytherapy. Nearly a third of men originally opting for surveillance went on to undergo a therapeutic intervention by 10 years.
Dr. Al Hussein Al Awamlh and his colleagues found that while 3- and 5-year follow-up studies in this cohort had shown declines in sexual function among men who underwent surgery compared with those who had radiation or active surveillance, by 10 years those differences had faded, with no clinically meaningful differences in sexual function scores between the surgery and surveillance groups. In an interview, Dr. Al Hussein Al Awamlh said that this finding likely reflected mainly age-related declines in function across the study population — though it could also reflect declines after converting from surveillance to surgery or gradual decline with radiation treatment, he acknowledged.
Men with favorable prognoses at baseline who underwent surgery saw significantly worse urinary incontinence at 10 years compared with those started on radiotherapy or active surveillance. And EBRT was associated with fewer incontinence issues compared with active surveillance.
Among the group of men with an unfavorable prognosis at baseline, 64% of whom underwent radical prostatectomy and 36% EBRT with ADT, surgery was associated with worse urinary incontinence but not worse sexual function throughout 10 years of follow up, compared to radiotherapy with androgen deprivation therapy.
Radiation-treated patients with unfavorable prognoses, meanwhile, saw significantly worse bowel function and hormone function at 10 years compared with patients who had undergone surgery.
Dr. Al Hussein Al Awamlh said that a strength of this study was that “we had enough patients to stratify functional outcomes based on disease prognosis.” Another key finding was that some of the outcomes changed over time. “For example, among the patients with unfavorable prognoses, at 10-year follow-up there was slightly worse bowel and hormone function seen associated with radiation with ADT compared with surgery,” he said — something not seen at earlier follow-up points.
The findings may help offer a more nuanced way to counsel patients, Dr. Al Hussein Al Awamlh noted. For example, the side effects associated with sexual function “are not as relevant for those with unfavorable disease,” he said.
While current prostate cancer guidelines do address quality of life in shared decision-making, he said, “hopefully this data may provide more insight on that.” For patients with favorable prognosis, the findings reinforce that “active surveillance is a great option because it avoids the effects associated with those other treatments.”
Ultimately, Dr. Al Hussein Al Awamlh said, “this is a patient preference issue. It’s important for patients to understand how different functions are affected and to decide what is better for them — what they can live with and what they cannot, provided all the options are oncologically safe.”
The study authors disclosed as limitations of their study its observational design, the potential for response bias among study participants, and small numbers for some of the measured outcomes.
In an interview, urologist Mark S. Litwin, MD, of the University of California Los Angeles, characterized the study as “a well-conducted very-long-term longitudinal cohort that tracked men long past the initial diagnosis and treatment. That empowered the Vanderbilt team to find differences in quality of life many years later and compare them to other older men who had not received treatment.”
The new findings, Dr. Litwin said, “are critical in showing that most men with prostate cancer do not die from it; hence, the quality-of-life effects end up being the key issues for decision-making.”
Dr. Al Hussein Al Awamlh and colleagues’ study was funded by grants from the National Institutes of Health, the Agency for Healthcare Research and Quality, and the Patient-Centered Outcomes Research Institute. Several coauthors disclosed funding from pharmaceutical and/or device manufacturers. Dr. Litwin disclosed no conflicts of interest related to his comment.
FROM JAMA
AI-guided colonoscopy results in more small adenomas detected
according to results from a large meta-analysis of randomized controlled trials.
But while adenoma detection rates increased by nearly 25%, compared with conventional care, the AI-guided procedures were also associated with an increase in unnecessary removal of non-neoplastic polyps. Little effect was seen on the detection of larger, advanced lesions.
The findings, published in Annals of Internal Medicine, are likely to change clinical guidelines in favor of AI-assisted procedures, said Cesare Hassan, MD, PhD, of Humanitas Research Hospital and University in Milan, Italy.
For their research, Dr. Hassan and his colleagues looked at results from 21 trials randomizing more than 18,000 patients to colonoscopy with computer-aided detection (CADe) or standard colonoscopy. Colonoscopy could be carried out for screening, surveillance, or diagnostic purposes. The included trials, which were all published in 2019 or later, took place in Asia, North America, and Europe. In most of the studies endoscopists were not blinded to treatment allocation.
The adenoma detection rate, or the proportion of individuals undergoing colonoscopy who had at least one adenoma detected and removed, was 44% in the CADe arms, compared with 35.9% assigned to standard care (relative risk [RR], 1.24; 95% CI, 1.16-1.33). The CADe patients also saw more non-neoplastic polyps removed: 0.52 per colonoscopy, compared with 0.34 for standard care. The increased adenoma detection rate appeared to be driven by a 55% decrease in the error or miss rate of adenomas at per-polyp analysis, the investigators wrote in their paper.
CADe did not increase the number of advanced adenomas (defined as greater than 10 mm, with high-grade dysplasia and villous histology) detected per colonoscopy. Rather, the benefit was “mainly limited to increased detection of diminutive (≤5 mm) adenomas,” the investigators wrote. Dr. Hassan commented that the lack of benefit for detecting larger adenomas was expected, as these are easier for endoscopists to identify visually.
The key limitation of the meta-analysis, Dr. Hassan said, was the fact that endoscopists in the studies could not be blinded. “We can assume there is a risk of bias in our estimates — that is why we describe the quality of evidence as low or moderate, never high. Through randomization we can control other aspects, especially the prevalence of disease, which avoids a scenario in which the endoscopist opts to treat riskier patients with CADe.” But the possibility of a change in the endoscopist’s performance when using these systems cannot be excluded.
Dr. Hassan commented that quantifying the risks, and costs, of overtreatment linked to CADe would require more investigation. “Any time I remove a polyp there’s a risk of perforation and bleeding,” he noted, though most of the unnecessary resections seen in the meta-analysis were of small hyperplastic polyps considered to be low risk for complications. Use of CADe was associated with only slight increases in procedure time, the investigators found.
In a multicenter Spanish study also published in Annals of Internal Medicine, Carolina Mangas-Sanjuan, MD, PhD, of the Hospital General Universitario Dr. Balmis, Alicante, Spain, and her colleagues looked at computer-aided detection of advanced colorectal neoplasias in a higher-risk cohort and saw little advantage over standard colonoscopy.
This study, which randomized 3,213 subjects, is the largest to date aimed at learning whether AI can improve the detection of advanced lesions. As in Dr. Hassan’s meta-analysis, the researchers did not see significant differences in the rates of detection for these larger lesions. Nor, in this study, did CADe did improve the global adenoma detection rate among the FIT positive individuals undergoing screening.
The detection rate of advanced colorectal neoplasias (advanced adenoma or advanced serrated polyp) was 34.8% with CADe (95% CI, 32.5%-37.2%) and 34.6% for standard colonoscopy (95% CI, 32.2%-36.9%); adjusted risk ratio, 1.01 [95% CI, 0.92-1.10]. The mean number of advanced colorectal neoplasias detected per colonoscopy was 0.54 for the intervention group, compared with 0.52 for standard care. For all adenomas, the detection rate was 64.2% with CADe vs 62% for controls.
Dr. Rodrigo Jover of the Hospital General Universitario Dr. Balmis, the study’s corresponding author, commented to this news organization that “while CADe systems are able to improve detection of small low-risk lesions, these devices are not yet able to detect more significant high-risk lesions. Therefore, there is still room for improvement if these systems are adequately trained with datasets of large, difficult-to-detect lesions.”
In an editorial comment on the Spanish and Italian studies Dennis Shung, MD, PhD of Yale University in New Haven, Connecticut, concluded that “this recent evidence suggests that CADe systems do not meaningfully improve the detection of larger (≥10 mm) clinically significant polyps. This tempers enthusiasm for CADe but does not negate the clear performance benefit for detecting adenomas of all sizes.”
How to integrate the AI systems into real-world practice is the real challenge ahead, Dr. Shung argued, noting that, in contrast to randomized trials, “several recent real-world studies have found no improvement in [adenoma detection rate] when CADe is deployed.” Lower trust in the systems can result in their underutilization, Dr. Shung argued, while higher trust can lead to overreliance. “How lgorithmic systems partner with clinicians and how these should be designed and refined across heterogeneous systems and contexts are necessary questions that must be explored to minimize disruption and lead to real-world effectiveness.”
Dr. Mangas-Sanjuan’s study was funded by a grant from Medtronic; Part of Dr. Hassan’s meta-analysis was supported by a European Commission grant to one co-author. Drs. Shung, Hassan, Manguas-Sanjuan, and Jover declared no financial conflicts of interest.
according to results from a large meta-analysis of randomized controlled trials.
But while adenoma detection rates increased by nearly 25%, compared with conventional care, the AI-guided procedures were also associated with an increase in unnecessary removal of non-neoplastic polyps. Little effect was seen on the detection of larger, advanced lesions.
The findings, published in Annals of Internal Medicine, are likely to change clinical guidelines in favor of AI-assisted procedures, said Cesare Hassan, MD, PhD, of Humanitas Research Hospital and University in Milan, Italy.
For their research, Dr. Hassan and his colleagues looked at results from 21 trials randomizing more than 18,000 patients to colonoscopy with computer-aided detection (CADe) or standard colonoscopy. Colonoscopy could be carried out for screening, surveillance, or diagnostic purposes. The included trials, which were all published in 2019 or later, took place in Asia, North America, and Europe. In most of the studies endoscopists were not blinded to treatment allocation.
The adenoma detection rate, or the proportion of individuals undergoing colonoscopy who had at least one adenoma detected and removed, was 44% in the CADe arms, compared with 35.9% assigned to standard care (relative risk [RR], 1.24; 95% CI, 1.16-1.33). The CADe patients also saw more non-neoplastic polyps removed: 0.52 per colonoscopy, compared with 0.34 for standard care. The increased adenoma detection rate appeared to be driven by a 55% decrease in the error or miss rate of adenomas at per-polyp analysis, the investigators wrote in their paper.
CADe did not increase the number of advanced adenomas (defined as greater than 10 mm, with high-grade dysplasia and villous histology) detected per colonoscopy. Rather, the benefit was “mainly limited to increased detection of diminutive (≤5 mm) adenomas,” the investigators wrote. Dr. Hassan commented that the lack of benefit for detecting larger adenomas was expected, as these are easier for endoscopists to identify visually.
The key limitation of the meta-analysis, Dr. Hassan said, was the fact that endoscopists in the studies could not be blinded. “We can assume there is a risk of bias in our estimates — that is why we describe the quality of evidence as low or moderate, never high. Through randomization we can control other aspects, especially the prevalence of disease, which avoids a scenario in which the endoscopist opts to treat riskier patients with CADe.” But the possibility of a change in the endoscopist’s performance when using these systems cannot be excluded.
Dr. Hassan commented that quantifying the risks, and costs, of overtreatment linked to CADe would require more investigation. “Any time I remove a polyp there’s a risk of perforation and bleeding,” he noted, though most of the unnecessary resections seen in the meta-analysis were of small hyperplastic polyps considered to be low risk for complications. Use of CADe was associated with only slight increases in procedure time, the investigators found.
In a multicenter Spanish study also published in Annals of Internal Medicine, Carolina Mangas-Sanjuan, MD, PhD, of the Hospital General Universitario Dr. Balmis, Alicante, Spain, and her colleagues looked at computer-aided detection of advanced colorectal neoplasias in a higher-risk cohort and saw little advantage over standard colonoscopy.
This study, which randomized 3,213 subjects, is the largest to date aimed at learning whether AI can improve the detection of advanced lesions. As in Dr. Hassan’s meta-analysis, the researchers did not see significant differences in the rates of detection for these larger lesions. Nor, in this study, did CADe did improve the global adenoma detection rate among the FIT positive individuals undergoing screening.
The detection rate of advanced colorectal neoplasias (advanced adenoma or advanced serrated polyp) was 34.8% with CADe (95% CI, 32.5%-37.2%) and 34.6% for standard colonoscopy (95% CI, 32.2%-36.9%); adjusted risk ratio, 1.01 [95% CI, 0.92-1.10]. The mean number of advanced colorectal neoplasias detected per colonoscopy was 0.54 for the intervention group, compared with 0.52 for standard care. For all adenomas, the detection rate was 64.2% with CADe vs 62% for controls.
Dr. Rodrigo Jover of the Hospital General Universitario Dr. Balmis, the study’s corresponding author, commented to this news organization that “while CADe systems are able to improve detection of small low-risk lesions, these devices are not yet able to detect more significant high-risk lesions. Therefore, there is still room for improvement if these systems are adequately trained with datasets of large, difficult-to-detect lesions.”
In an editorial comment on the Spanish and Italian studies Dennis Shung, MD, PhD of Yale University in New Haven, Connecticut, concluded that “this recent evidence suggests that CADe systems do not meaningfully improve the detection of larger (≥10 mm) clinically significant polyps. This tempers enthusiasm for CADe but does not negate the clear performance benefit for detecting adenomas of all sizes.”
How to integrate the AI systems into real-world practice is the real challenge ahead, Dr. Shung argued, noting that, in contrast to randomized trials, “several recent real-world studies have found no improvement in [adenoma detection rate] when CADe is deployed.” Lower trust in the systems can result in their underutilization, Dr. Shung argued, while higher trust can lead to overreliance. “How lgorithmic systems partner with clinicians and how these should be designed and refined across heterogeneous systems and contexts are necessary questions that must be explored to minimize disruption and lead to real-world effectiveness.”
Dr. Mangas-Sanjuan’s study was funded by a grant from Medtronic; Part of Dr. Hassan’s meta-analysis was supported by a European Commission grant to one co-author. Drs. Shung, Hassan, Manguas-Sanjuan, and Jover declared no financial conflicts of interest.
according to results from a large meta-analysis of randomized controlled trials.
But while adenoma detection rates increased by nearly 25%, compared with conventional care, the AI-guided procedures were also associated with an increase in unnecessary removal of non-neoplastic polyps. Little effect was seen on the detection of larger, advanced lesions.
The findings, published in Annals of Internal Medicine, are likely to change clinical guidelines in favor of AI-assisted procedures, said Cesare Hassan, MD, PhD, of Humanitas Research Hospital and University in Milan, Italy.
For their research, Dr. Hassan and his colleagues looked at results from 21 trials randomizing more than 18,000 patients to colonoscopy with computer-aided detection (CADe) or standard colonoscopy. Colonoscopy could be carried out for screening, surveillance, or diagnostic purposes. The included trials, which were all published in 2019 or later, took place in Asia, North America, and Europe. In most of the studies endoscopists were not blinded to treatment allocation.
The adenoma detection rate, or the proportion of individuals undergoing colonoscopy who had at least one adenoma detected and removed, was 44% in the CADe arms, compared with 35.9% assigned to standard care (relative risk [RR], 1.24; 95% CI, 1.16-1.33). The CADe patients also saw more non-neoplastic polyps removed: 0.52 per colonoscopy, compared with 0.34 for standard care. The increased adenoma detection rate appeared to be driven by a 55% decrease in the error or miss rate of adenomas at per-polyp analysis, the investigators wrote in their paper.
CADe did not increase the number of advanced adenomas (defined as greater than 10 mm, with high-grade dysplasia and villous histology) detected per colonoscopy. Rather, the benefit was “mainly limited to increased detection of diminutive (≤5 mm) adenomas,” the investigators wrote. Dr. Hassan commented that the lack of benefit for detecting larger adenomas was expected, as these are easier for endoscopists to identify visually.
The key limitation of the meta-analysis, Dr. Hassan said, was the fact that endoscopists in the studies could not be blinded. “We can assume there is a risk of bias in our estimates — that is why we describe the quality of evidence as low or moderate, never high. Through randomization we can control other aspects, especially the prevalence of disease, which avoids a scenario in which the endoscopist opts to treat riskier patients with CADe.” But the possibility of a change in the endoscopist’s performance when using these systems cannot be excluded.
Dr. Hassan commented that quantifying the risks, and costs, of overtreatment linked to CADe would require more investigation. “Any time I remove a polyp there’s a risk of perforation and bleeding,” he noted, though most of the unnecessary resections seen in the meta-analysis were of small hyperplastic polyps considered to be low risk for complications. Use of CADe was associated with only slight increases in procedure time, the investigators found.
In a multicenter Spanish study also published in Annals of Internal Medicine, Carolina Mangas-Sanjuan, MD, PhD, of the Hospital General Universitario Dr. Balmis, Alicante, Spain, and her colleagues looked at computer-aided detection of advanced colorectal neoplasias in a higher-risk cohort and saw little advantage over standard colonoscopy.
This study, which randomized 3,213 subjects, is the largest to date aimed at learning whether AI can improve the detection of advanced lesions. As in Dr. Hassan’s meta-analysis, the researchers did not see significant differences in the rates of detection for these larger lesions. Nor, in this study, did CADe did improve the global adenoma detection rate among the FIT positive individuals undergoing screening.
The detection rate of advanced colorectal neoplasias (advanced adenoma or advanced serrated polyp) was 34.8% with CADe (95% CI, 32.5%-37.2%) and 34.6% for standard colonoscopy (95% CI, 32.2%-36.9%); adjusted risk ratio, 1.01 [95% CI, 0.92-1.10]. The mean number of advanced colorectal neoplasias detected per colonoscopy was 0.54 for the intervention group, compared with 0.52 for standard care. For all adenomas, the detection rate was 64.2% with CADe vs 62% for controls.
Dr. Rodrigo Jover of the Hospital General Universitario Dr. Balmis, the study’s corresponding author, commented to this news organization that “while CADe systems are able to improve detection of small low-risk lesions, these devices are not yet able to detect more significant high-risk lesions. Therefore, there is still room for improvement if these systems are adequately trained with datasets of large, difficult-to-detect lesions.”
In an editorial comment on the Spanish and Italian studies Dennis Shung, MD, PhD of Yale University in New Haven, Connecticut, concluded that “this recent evidence suggests that CADe systems do not meaningfully improve the detection of larger (≥10 mm) clinically significant polyps. This tempers enthusiasm for CADe but does not negate the clear performance benefit for detecting adenomas of all sizes.”
How to integrate the AI systems into real-world practice is the real challenge ahead, Dr. Shung argued, noting that, in contrast to randomized trials, “several recent real-world studies have found no improvement in [adenoma detection rate] when CADe is deployed.” Lower trust in the systems can result in their underutilization, Dr. Shung argued, while higher trust can lead to overreliance. “How lgorithmic systems partner with clinicians and how these should be designed and refined across heterogeneous systems and contexts are necessary questions that must be explored to minimize disruption and lead to real-world effectiveness.”
Dr. Mangas-Sanjuan’s study was funded by a grant from Medtronic; Part of Dr. Hassan’s meta-analysis was supported by a European Commission grant to one co-author. Drs. Shung, Hassan, Manguas-Sanjuan, and Jover declared no financial conflicts of interest.
FROM ANNALS OF INTERNAL MEDICINE
AGA clinical practice guideline affirms role of biomarkers in Crohn’s disease management
, offering the most specific evidence-based recommendations yet for the use of fecal calprotectin (FCP) and serum C-reactive protein (CRP) in assessing disease activity.
Repeated monitoring with endoscopy allows for an objective assessment of inflammation and mucosal healing compared with symptoms alone. However, relying solely on endoscopy to guide management is an approach “limited by cost and resource utilization, invasiveness, and reduced patient acceptability,” wrote guideline authors on behalf of the AGA Clinical Guidelines Committee. The guideline was published online Nov. 17 in Gastroenterology.
“Use of biomarkers is no longer considered experimental and should be an integral part of IBD care and monitoring,” said Ashwin Ananthakrishnan, MBBS, MPH, a gastroenterologist with Massachusetts General Hospital in Boston and first author of the guideline. “We need further studies to define their optimal longitudinal use, but at a given time point, there is now abundant evidence that biomarkers provide significant incremental benefit over symptoms alone in assessing a patient’s status.”
Using evidence from randomized controlled trials and observational studies, and applying it to common clinical scenarios, there are conditional recommendations on the use of biomarkers in patients with established, diagnosed disease who were asymptomatic, symptomatic, or in surgically induced remission. Those recommendations, laid out in a detailed Clinical Decision Support Tool, include the following:
For asymptomatic patients: Check CRP and FCP every 6-12 months. Patients with normal levels, and who have endoscopically confirmed remission within the last 3 years without any subsequent change in symptoms or treatment, need not undergo endoscopy and can be followed with biomarker and clinical checks alone. If CRP or FCP are elevated (defined as CRP ≥ 5 mg/L, FCP ≥ 150 mcg/g), consider repeating biomarkers and/or performing endoscopic assessment of disease activity before adjusting treatment.
For mildly symptomatic patients: Role of biomarker testing may be limited and endoscopic or radiologic assessment may be required to assess active inflammation given the higher rate of false positive and false negative results with biomarkers in this population.
For patients with more severe symptoms: Elevated CRP or FCP can be used to guide treatment adjustment without endoscopic confirmation in certain situations. Normal levels may be false negative and should be confirmed by endoscopic assessment of disease activity.
For patients in surgically induced remission with a low likelihood of recurrence: FCP levels below 50 mcg/g can be used in lieu of routine endoscopic assessment within the first year after surgery. Higher FCP levels should prompt endoscopic assessment.
For patients in surgically induced remission with a high risk of recurrence: Do not rely on biomarkers. Perform endoscopic assessment.
All recommendations were deemed of low to moderate certainty based on results from randomized clinical trials and observational studies that utilized these biomarkers in patients with Crohn’s disease. Citing a dearth of quality evidence, the guideline authors determined they could not make recommendations on the use of a third proprietary biomarker — the endoscopic healing index (EHI).
Recent AGA Clinical Practice Guidelines on the role of biomarkers in ulcerative colitis, published in March, also support a strong role for fecal and blood biomarkers, determining when these can be used to avoid unneeded endoscopic assessments. However, in patients with Crohn’s disease, symptoms correlate less well with endoscopic activity.
As a result, “biomarker performance was acceptable only in asymptomatic individuals who had recently confirmed endoscopic remission; in those without recent endoscopic assessment, test performance was suboptimal.” In addition, the weaker correlation between symptoms and endoscopic activity in Crohn’s “reduced the utility of biomarker measurement to infer disease activity in those with mild symptoms.”
The guidelines were fully funded by the AGA Institute. The authors disclosed a number of potential conflicts of interest, including receiving research grants, as well as consulting and speaking fees, from pharmaceutical companies.
, offering the most specific evidence-based recommendations yet for the use of fecal calprotectin (FCP) and serum C-reactive protein (CRP) in assessing disease activity.
Repeated monitoring with endoscopy allows for an objective assessment of inflammation and mucosal healing compared with symptoms alone. However, relying solely on endoscopy to guide management is an approach “limited by cost and resource utilization, invasiveness, and reduced patient acceptability,” wrote guideline authors on behalf of the AGA Clinical Guidelines Committee. The guideline was published online Nov. 17 in Gastroenterology.
“Use of biomarkers is no longer considered experimental and should be an integral part of IBD care and monitoring,” said Ashwin Ananthakrishnan, MBBS, MPH, a gastroenterologist with Massachusetts General Hospital in Boston and first author of the guideline. “We need further studies to define their optimal longitudinal use, but at a given time point, there is now abundant evidence that biomarkers provide significant incremental benefit over symptoms alone in assessing a patient’s status.”
Using evidence from randomized controlled trials and observational studies, and applying it to common clinical scenarios, there are conditional recommendations on the use of biomarkers in patients with established, diagnosed disease who were asymptomatic, symptomatic, or in surgically induced remission. Those recommendations, laid out in a detailed Clinical Decision Support Tool, include the following:
For asymptomatic patients: Check CRP and FCP every 6-12 months. Patients with normal levels, and who have endoscopically confirmed remission within the last 3 years without any subsequent change in symptoms or treatment, need not undergo endoscopy and can be followed with biomarker and clinical checks alone. If CRP or FCP are elevated (defined as CRP ≥ 5 mg/L, FCP ≥ 150 mcg/g), consider repeating biomarkers and/or performing endoscopic assessment of disease activity before adjusting treatment.
For mildly symptomatic patients: Role of biomarker testing may be limited and endoscopic or radiologic assessment may be required to assess active inflammation given the higher rate of false positive and false negative results with biomarkers in this population.
For patients with more severe symptoms: Elevated CRP or FCP can be used to guide treatment adjustment without endoscopic confirmation in certain situations. Normal levels may be false negative and should be confirmed by endoscopic assessment of disease activity.
For patients in surgically induced remission with a low likelihood of recurrence: FCP levels below 50 mcg/g can be used in lieu of routine endoscopic assessment within the first year after surgery. Higher FCP levels should prompt endoscopic assessment.
For patients in surgically induced remission with a high risk of recurrence: Do not rely on biomarkers. Perform endoscopic assessment.
All recommendations were deemed of low to moderate certainty based on results from randomized clinical trials and observational studies that utilized these biomarkers in patients with Crohn’s disease. Citing a dearth of quality evidence, the guideline authors determined they could not make recommendations on the use of a third proprietary biomarker — the endoscopic healing index (EHI).
Recent AGA Clinical Practice Guidelines on the role of biomarkers in ulcerative colitis, published in March, also support a strong role for fecal and blood biomarkers, determining when these can be used to avoid unneeded endoscopic assessments. However, in patients with Crohn’s disease, symptoms correlate less well with endoscopic activity.
As a result, “biomarker performance was acceptable only in asymptomatic individuals who had recently confirmed endoscopic remission; in those without recent endoscopic assessment, test performance was suboptimal.” In addition, the weaker correlation between symptoms and endoscopic activity in Crohn’s “reduced the utility of biomarker measurement to infer disease activity in those with mild symptoms.”
The guidelines were fully funded by the AGA Institute. The authors disclosed a number of potential conflicts of interest, including receiving research grants, as well as consulting and speaking fees, from pharmaceutical companies.
, offering the most specific evidence-based recommendations yet for the use of fecal calprotectin (FCP) and serum C-reactive protein (CRP) in assessing disease activity.
Repeated monitoring with endoscopy allows for an objective assessment of inflammation and mucosal healing compared with symptoms alone. However, relying solely on endoscopy to guide management is an approach “limited by cost and resource utilization, invasiveness, and reduced patient acceptability,” wrote guideline authors on behalf of the AGA Clinical Guidelines Committee. The guideline was published online Nov. 17 in Gastroenterology.
“Use of biomarkers is no longer considered experimental and should be an integral part of IBD care and monitoring,” said Ashwin Ananthakrishnan, MBBS, MPH, a gastroenterologist with Massachusetts General Hospital in Boston and first author of the guideline. “We need further studies to define their optimal longitudinal use, but at a given time point, there is now abundant evidence that biomarkers provide significant incremental benefit over symptoms alone in assessing a patient’s status.”
Using evidence from randomized controlled trials and observational studies, and applying it to common clinical scenarios, there are conditional recommendations on the use of biomarkers in patients with established, diagnosed disease who were asymptomatic, symptomatic, or in surgically induced remission. Those recommendations, laid out in a detailed Clinical Decision Support Tool, include the following:
For asymptomatic patients: Check CRP and FCP every 6-12 months. Patients with normal levels, and who have endoscopically confirmed remission within the last 3 years without any subsequent change in symptoms or treatment, need not undergo endoscopy and can be followed with biomarker and clinical checks alone. If CRP or FCP are elevated (defined as CRP ≥ 5 mg/L, FCP ≥ 150 mcg/g), consider repeating biomarkers and/or performing endoscopic assessment of disease activity before adjusting treatment.
For mildly symptomatic patients: Role of biomarker testing may be limited and endoscopic or radiologic assessment may be required to assess active inflammation given the higher rate of false positive and false negative results with biomarkers in this population.
For patients with more severe symptoms: Elevated CRP or FCP can be used to guide treatment adjustment without endoscopic confirmation in certain situations. Normal levels may be false negative and should be confirmed by endoscopic assessment of disease activity.
For patients in surgically induced remission with a low likelihood of recurrence: FCP levels below 50 mcg/g can be used in lieu of routine endoscopic assessment within the first year after surgery. Higher FCP levels should prompt endoscopic assessment.
For patients in surgically induced remission with a high risk of recurrence: Do not rely on biomarkers. Perform endoscopic assessment.
All recommendations were deemed of low to moderate certainty based on results from randomized clinical trials and observational studies that utilized these biomarkers in patients with Crohn’s disease. Citing a dearth of quality evidence, the guideline authors determined they could not make recommendations on the use of a third proprietary biomarker — the endoscopic healing index (EHI).
Recent AGA Clinical Practice Guidelines on the role of biomarkers in ulcerative colitis, published in March, also support a strong role for fecal and blood biomarkers, determining when these can be used to avoid unneeded endoscopic assessments. However, in patients with Crohn’s disease, symptoms correlate less well with endoscopic activity.
As a result, “biomarker performance was acceptable only in asymptomatic individuals who had recently confirmed endoscopic remission; in those without recent endoscopic assessment, test performance was suboptimal.” In addition, the weaker correlation between symptoms and endoscopic activity in Crohn’s “reduced the utility of biomarker measurement to infer disease activity in those with mild symptoms.”
The guidelines were fully funded by the AGA Institute. The authors disclosed a number of potential conflicts of interest, including receiving research grants, as well as consulting and speaking fees, from pharmaceutical companies.
FROM GASTROENTEROLOGY
From failure to hope: Tracking the changing landscape of Alzheimer’s therapies
In 2014 neurologist Jeffrey L. Cummings, MD, startled the Alzheimer’s disease research world with a paper that laid bare the alarmingly high failure rate of Alzheimer’s disease therapies in development.
Publishing in the journal Alzheimer’s Research & Therapy, Dr. Cummings and his colleagues determined that 99.6% of all therapies tested between 2002 and 2012 had failed. Since downloaded some 75,000 times, Dr. Cumming’s “99% paper,” as it came to be nicknamed, led him to look more deeply and thoroughly at Alzheimer’s disease drugs in the pipeline, and describe them in a readable, user-friendly way.
His “Alzheimer’s Drug Development Pipeline” report, in the journal Alzheimer’s & Dementia, classifies therapies by their targets, their mechanisms of action, and where they stand in the development process.
Heavy on color-coded visuals, this snapshot of Alzheimer’s disease therapies is widely consulted by industry, researchers, and clinicians. Over time this report – which first documented a crisis – has come to show something more optimistic: an increasingly crowded pipeline reflecting a broad array of treatment approaches. Dr. Cummings wants more people to know that Alzheimer’s disease drug research, which now includes the first two Food and Drug Administration–approved monoclonal antibodies against amyloid-beta, is not the bleak landscape that it was in recent memory.
Lately, with the help of a grant from the National Institute on Aging, Dr. Cummings and his group have been working to expand on their reports to build an even more user-friendly database that can be searched by people in all corners of the neurodegenerative disease world. Dr. Cummings says he plans for this public-facing database to be up and running by year end.
Neurology Reviews spoke with Dr. Cummings, who is a member of the publication’s Editorial Advisory Board, about the genesis of his influential drug-tracking effort, how it has evolved, and what has been learned from it over the years.
How did all this begin?
Already in 2014 there was a dialogue going on was about the high failure rate for Alzheimer’s drugs. And I thought: “there’s probably a number that can be assigned to that.” And when it turned out to be 99.6%, that generated a huge amount of interest. That’s when I realized what interests me also interests the world. And that I was uniquely positioned after that point to do something annually.
How do you create your annual report, and how do you classify the drugs in it when some might act on little-understood pathways or mechanisms?
We capture information available on clinicaltrials.gov. We are notified immediately of any new Alzheimer-related trials, and we automate everything that is possible to automate. But there is still some human curation required. Most of that is around mechanisms. If it’s a monoclonal antibody directed at amyloid-beta, that’s not difficult to categorize. But with the small molecules especially, it can be more complicated.
We often look to see how the sponsor describes the drug and what their perception of the primary target is. A resource of great importance to us is CADRO, Common Alzheimer’s and Related Dementias Disease Research Ontology, which describes about 20 mechanisms that a group of scientists sponsored by the National Institutes of Health and the Alzheimer’s Association have agreed on. Inflammation, epigenetics, and oxidation are just a few that most people know. CADRO is organized in a very specific way that allows us to go to the mechanism and relate it to the target. But we do try to be humble and acknowledge we probably make some errors in this.
Are you able to capture every Alzheimer’s drug in development globally?
If they’re on clinicaltrials.gov, they’re in our database. But we think there’s about 15% of drugs in the world that aren’t for some reason on clinicaltrials.gov – so we know we are comprehensive, but not quite exhaustive. I’m in kind of quandary about whether to search for that other 15%. But we do always acknowledge that we’re not 100% exhaustive.
Who are the report’s main readers?
Drug developers use it for investor discussions, and also to understand the competition and the landscape. The competition might be a drug with the same mechanism, and the landscape might be drugs coming into the Alzheimer’s disease world. So if someone is developing a PDE-5 inhibitor for mild dementia, for example, they can see that other people are working on a PDE-5 inhibitor for moderate dementia, and there’s no overlap. Investors use the report to make decisions about which horse in the race to bet on. And of course it’s used by academics and clinicians to learn which are the new drugs in the pipeline, which drugs have fallen out of the pipeline, how are biomarkers changing trials, what are the new outcomes.
It’s really become a community project. Investigators will email me and say “Jeff, we’re in phase 1, make sure it’s on your map.” Or, “you forgot our agent! We’re disappointed.” When that occurs it’s because they were not in a trial on the index date – the 1 day in our publication when everything we say in the paper is true. A trial initiated 1 day later won’t make the report for that year.
What about patients and families? Are they able to use the report as well?
One of the things we want to expand with the new database is its usefulness for patients. Among the new data display approaches that we have is a world map where you can go click on a dot near your home and find active trials. That’s something patients and families want to know, right? There’s 140 drugs in clinical trials, there must be one for me, how would I get to it? Soon we will have quite a good public portal so if you want to go in and see what new monoclonal antibodies are in phase 2, you can do that with drop-down menus. It’s a very easy to use site that anyone can explore.
Looking back at your last decade tracking drugs, what are some lessons learned and what are some of the more exciting drug categories to emerge?
My answer to this question is: Biologics rule. The main successes have been in biologics, in the monoclonal antibodies against amyloid, like the two FDA-approved agents lecanemab and aducanumab. But I think that the monoclonals, while I’m really happy to have them, are a first step. If you look back at tacrine, the first drug approved in 1993 for Alzheimer’s disease, it was a very difficult drug with lots of side effects. But then within 3 years we had donepezil, which was a very benign drug. I feel that a similar evolution is likely with regard to these antibodies. The first ones, we know, have big challenges, and you learn from those challenges and you just keep improving them. But you have to start somewhere, and you have to validate that target. Now I think that amyloid is validated.
What other approaches are interesting to you?
We have seen dramatic imaging results with marked reductions in neurofibrillary tangles from an antisense oligonucleotide aimed at tau protein. And there are two very active areas in the pipeline: inflammation and synaptic plasticity. Each has roughly 20 drugs apiece in development across all phases. And as you know, both synaptic plasticity and inflammation are represented across neurodegenerative conditions.
Your annual report has always focused on drugs to treat Alzheimer’s disease. Will the new database cover other types of dementia and neurodegenerative diseases?
That’s an obvious next step. I’m hoping that late this year we will have funding to expand the database into frontotemporal lobar degenerations, which will include all the tauopathies. And there’s also an overlap with TDP-43 diseases, so we’ll bring all of that in too. We have a new initiative on Parkinson’s disease and dementia with Lewy bodies that I hope will materialize by next year. My goal is that this will eventually become a neurodegenerative disease therapies database. The really interesting drugs right now are being tested in more than one neurodegenerative disease, and we should look at those more carefully. It will be more feasible to do that if they’re on the same data set.
What about other therapy classes?
We aim to be more serious about devices.
What will you call the database?
The Clinical Trial Observatory. We may start by calling it the Alzheimer’s Disease Clinical Trial Observatory. But the intention, obviously, is to go way beyond Alzheimer’s disease. The database is managed by a terrific team of data scientists at Cleveland Clinic, led by Feixiong Cheng, PhD.
The annual pipeline report is very much associated with you. Is the database going to be different?
Right now, I’m like the grandfather of this project. I won’t be around forever. This will have to pass on, and we’re already talking about succession. We’re thinking about how to make sure this community resource continues to be a community resource. Also, over all these years the annual report reflected my perspective. But with a database, many more people will be able to share their perspectives. I happen to think that “biologics rule,” but others might look at the data, see different scientific currents, and draw different conclusions. That will create a rich dialogue.
Do you think your reports have changed people’s perspectives on Alzheimer’s disease therapies? There’s a widely held idea that the field is exclusively focused on amyloid, or even dead-ended, but the papers seem to show something different.
We think this effort has helped, and will continue to help and foster investment and growth in treatments for our patients. It really does show how diverse the clinical trials landscape is now. People are surprised to learn of the number and diversity of approaches. Just last week I was presenting at the Center for Brain Health in Dallas and there was a doctor in the audience who was a caregiver to his wife with Alzheimer’s disease. He came up afterwards and said, “I had no idea there were so many drugs in clinical trials,” because there’s no way to find out if you don’t know about this resource.
Dr. Cummings discloses consulting for a range of companies working in Alzheimer’s therapies and diagnostics, including Acadia, Alkahest, AlphaCognition, AriBio, Avanir, Axsome, Behren, Biogen, Biohaven, Cassava, Cerecin, Cortexyme, Diadem, EIP Pharma, Eisai, GemVax, Genentech, Green Valley, Grifols, Janssen, LSP, Merck, NervGen, Novo Nordisk, Oligomerix, Ono, Otsuka, PRODEO, ReMYND, Renew, Resverlogix, Roche, Signant Health, Suven, United Neuroscience, and Unlearn AI. He has received several grants from the National Institute on Aging.
In 2014 neurologist Jeffrey L. Cummings, MD, startled the Alzheimer’s disease research world with a paper that laid bare the alarmingly high failure rate of Alzheimer’s disease therapies in development.
Publishing in the journal Alzheimer’s Research & Therapy, Dr. Cummings and his colleagues determined that 99.6% of all therapies tested between 2002 and 2012 had failed. Since downloaded some 75,000 times, Dr. Cumming’s “99% paper,” as it came to be nicknamed, led him to look more deeply and thoroughly at Alzheimer’s disease drugs in the pipeline, and describe them in a readable, user-friendly way.
His “Alzheimer’s Drug Development Pipeline” report, in the journal Alzheimer’s & Dementia, classifies therapies by their targets, their mechanisms of action, and where they stand in the development process.
Heavy on color-coded visuals, this snapshot of Alzheimer’s disease therapies is widely consulted by industry, researchers, and clinicians. Over time this report – which first documented a crisis – has come to show something more optimistic: an increasingly crowded pipeline reflecting a broad array of treatment approaches. Dr. Cummings wants more people to know that Alzheimer’s disease drug research, which now includes the first two Food and Drug Administration–approved monoclonal antibodies against amyloid-beta, is not the bleak landscape that it was in recent memory.
Lately, with the help of a grant from the National Institute on Aging, Dr. Cummings and his group have been working to expand on their reports to build an even more user-friendly database that can be searched by people in all corners of the neurodegenerative disease world. Dr. Cummings says he plans for this public-facing database to be up and running by year end.
Neurology Reviews spoke with Dr. Cummings, who is a member of the publication’s Editorial Advisory Board, about the genesis of his influential drug-tracking effort, how it has evolved, and what has been learned from it over the years.
How did all this begin?
Already in 2014 there was a dialogue going on was about the high failure rate for Alzheimer’s drugs. And I thought: “there’s probably a number that can be assigned to that.” And when it turned out to be 99.6%, that generated a huge amount of interest. That’s when I realized what interests me also interests the world. And that I was uniquely positioned after that point to do something annually.
How do you create your annual report, and how do you classify the drugs in it when some might act on little-understood pathways or mechanisms?
We capture information available on clinicaltrials.gov. We are notified immediately of any new Alzheimer-related trials, and we automate everything that is possible to automate. But there is still some human curation required. Most of that is around mechanisms. If it’s a monoclonal antibody directed at amyloid-beta, that’s not difficult to categorize. But with the small molecules especially, it can be more complicated.
We often look to see how the sponsor describes the drug and what their perception of the primary target is. A resource of great importance to us is CADRO, Common Alzheimer’s and Related Dementias Disease Research Ontology, which describes about 20 mechanisms that a group of scientists sponsored by the National Institutes of Health and the Alzheimer’s Association have agreed on. Inflammation, epigenetics, and oxidation are just a few that most people know. CADRO is organized in a very specific way that allows us to go to the mechanism and relate it to the target. But we do try to be humble and acknowledge we probably make some errors in this.
Are you able to capture every Alzheimer’s drug in development globally?
If they’re on clinicaltrials.gov, they’re in our database. But we think there’s about 15% of drugs in the world that aren’t for some reason on clinicaltrials.gov – so we know we are comprehensive, but not quite exhaustive. I’m in kind of quandary about whether to search for that other 15%. But we do always acknowledge that we’re not 100% exhaustive.
Who are the report’s main readers?
Drug developers use it for investor discussions, and also to understand the competition and the landscape. The competition might be a drug with the same mechanism, and the landscape might be drugs coming into the Alzheimer’s disease world. So if someone is developing a PDE-5 inhibitor for mild dementia, for example, they can see that other people are working on a PDE-5 inhibitor for moderate dementia, and there’s no overlap. Investors use the report to make decisions about which horse in the race to bet on. And of course it’s used by academics and clinicians to learn which are the new drugs in the pipeline, which drugs have fallen out of the pipeline, how are biomarkers changing trials, what are the new outcomes.
It’s really become a community project. Investigators will email me and say “Jeff, we’re in phase 1, make sure it’s on your map.” Or, “you forgot our agent! We’re disappointed.” When that occurs it’s because they were not in a trial on the index date – the 1 day in our publication when everything we say in the paper is true. A trial initiated 1 day later won’t make the report for that year.
What about patients and families? Are they able to use the report as well?
One of the things we want to expand with the new database is its usefulness for patients. Among the new data display approaches that we have is a world map where you can go click on a dot near your home and find active trials. That’s something patients and families want to know, right? There’s 140 drugs in clinical trials, there must be one for me, how would I get to it? Soon we will have quite a good public portal so if you want to go in and see what new monoclonal antibodies are in phase 2, you can do that with drop-down menus. It’s a very easy to use site that anyone can explore.
Looking back at your last decade tracking drugs, what are some lessons learned and what are some of the more exciting drug categories to emerge?
My answer to this question is: Biologics rule. The main successes have been in biologics, in the monoclonal antibodies against amyloid, like the two FDA-approved agents lecanemab and aducanumab. But I think that the monoclonals, while I’m really happy to have them, are a first step. If you look back at tacrine, the first drug approved in 1993 for Alzheimer’s disease, it was a very difficult drug with lots of side effects. But then within 3 years we had donepezil, which was a very benign drug. I feel that a similar evolution is likely with regard to these antibodies. The first ones, we know, have big challenges, and you learn from those challenges and you just keep improving them. But you have to start somewhere, and you have to validate that target. Now I think that amyloid is validated.
What other approaches are interesting to you?
We have seen dramatic imaging results with marked reductions in neurofibrillary tangles from an antisense oligonucleotide aimed at tau protein. And there are two very active areas in the pipeline: inflammation and synaptic plasticity. Each has roughly 20 drugs apiece in development across all phases. And as you know, both synaptic plasticity and inflammation are represented across neurodegenerative conditions.
Your annual report has always focused on drugs to treat Alzheimer’s disease. Will the new database cover other types of dementia and neurodegenerative diseases?
That’s an obvious next step. I’m hoping that late this year we will have funding to expand the database into frontotemporal lobar degenerations, which will include all the tauopathies. And there’s also an overlap with TDP-43 diseases, so we’ll bring all of that in too. We have a new initiative on Parkinson’s disease and dementia with Lewy bodies that I hope will materialize by next year. My goal is that this will eventually become a neurodegenerative disease therapies database. The really interesting drugs right now are being tested in more than one neurodegenerative disease, and we should look at those more carefully. It will be more feasible to do that if they’re on the same data set.
What about other therapy classes?
We aim to be more serious about devices.
What will you call the database?
The Clinical Trial Observatory. We may start by calling it the Alzheimer’s Disease Clinical Trial Observatory. But the intention, obviously, is to go way beyond Alzheimer’s disease. The database is managed by a terrific team of data scientists at Cleveland Clinic, led by Feixiong Cheng, PhD.
The annual pipeline report is very much associated with you. Is the database going to be different?
Right now, I’m like the grandfather of this project. I won’t be around forever. This will have to pass on, and we’re already talking about succession. We’re thinking about how to make sure this community resource continues to be a community resource. Also, over all these years the annual report reflected my perspective. But with a database, many more people will be able to share their perspectives. I happen to think that “biologics rule,” but others might look at the data, see different scientific currents, and draw different conclusions. That will create a rich dialogue.
Do you think your reports have changed people’s perspectives on Alzheimer’s disease therapies? There’s a widely held idea that the field is exclusively focused on amyloid, or even dead-ended, but the papers seem to show something different.
We think this effort has helped, and will continue to help and foster investment and growth in treatments for our patients. It really does show how diverse the clinical trials landscape is now. People are surprised to learn of the number and diversity of approaches. Just last week I was presenting at the Center for Brain Health in Dallas and there was a doctor in the audience who was a caregiver to his wife with Alzheimer’s disease. He came up afterwards and said, “I had no idea there were so many drugs in clinical trials,” because there’s no way to find out if you don’t know about this resource.
Dr. Cummings discloses consulting for a range of companies working in Alzheimer’s therapies and diagnostics, including Acadia, Alkahest, AlphaCognition, AriBio, Avanir, Axsome, Behren, Biogen, Biohaven, Cassava, Cerecin, Cortexyme, Diadem, EIP Pharma, Eisai, GemVax, Genentech, Green Valley, Grifols, Janssen, LSP, Merck, NervGen, Novo Nordisk, Oligomerix, Ono, Otsuka, PRODEO, ReMYND, Renew, Resverlogix, Roche, Signant Health, Suven, United Neuroscience, and Unlearn AI. He has received several grants from the National Institute on Aging.
In 2014 neurologist Jeffrey L. Cummings, MD, startled the Alzheimer’s disease research world with a paper that laid bare the alarmingly high failure rate of Alzheimer’s disease therapies in development.
Publishing in the journal Alzheimer’s Research & Therapy, Dr. Cummings and his colleagues determined that 99.6% of all therapies tested between 2002 and 2012 had failed. Since downloaded some 75,000 times, Dr. Cumming’s “99% paper,” as it came to be nicknamed, led him to look more deeply and thoroughly at Alzheimer’s disease drugs in the pipeline, and describe them in a readable, user-friendly way.
His “Alzheimer’s Drug Development Pipeline” report, in the journal Alzheimer’s & Dementia, classifies therapies by their targets, their mechanisms of action, and where they stand in the development process.
Heavy on color-coded visuals, this snapshot of Alzheimer’s disease therapies is widely consulted by industry, researchers, and clinicians. Over time this report – which first documented a crisis – has come to show something more optimistic: an increasingly crowded pipeline reflecting a broad array of treatment approaches. Dr. Cummings wants more people to know that Alzheimer’s disease drug research, which now includes the first two Food and Drug Administration–approved monoclonal antibodies against amyloid-beta, is not the bleak landscape that it was in recent memory.
Lately, with the help of a grant from the National Institute on Aging, Dr. Cummings and his group have been working to expand on their reports to build an even more user-friendly database that can be searched by people in all corners of the neurodegenerative disease world. Dr. Cummings says he plans for this public-facing database to be up and running by year end.
Neurology Reviews spoke with Dr. Cummings, who is a member of the publication’s Editorial Advisory Board, about the genesis of his influential drug-tracking effort, how it has evolved, and what has been learned from it over the years.
How did all this begin?
Already in 2014 there was a dialogue going on was about the high failure rate for Alzheimer’s drugs. And I thought: “there’s probably a number that can be assigned to that.” And when it turned out to be 99.6%, that generated a huge amount of interest. That’s when I realized what interests me also interests the world. And that I was uniquely positioned after that point to do something annually.
How do you create your annual report, and how do you classify the drugs in it when some might act on little-understood pathways or mechanisms?
We capture information available on clinicaltrials.gov. We are notified immediately of any new Alzheimer-related trials, and we automate everything that is possible to automate. But there is still some human curation required. Most of that is around mechanisms. If it’s a monoclonal antibody directed at amyloid-beta, that’s not difficult to categorize. But with the small molecules especially, it can be more complicated.
We often look to see how the sponsor describes the drug and what their perception of the primary target is. A resource of great importance to us is CADRO, Common Alzheimer’s and Related Dementias Disease Research Ontology, which describes about 20 mechanisms that a group of scientists sponsored by the National Institutes of Health and the Alzheimer’s Association have agreed on. Inflammation, epigenetics, and oxidation are just a few that most people know. CADRO is organized in a very specific way that allows us to go to the mechanism and relate it to the target. But we do try to be humble and acknowledge we probably make some errors in this.
Are you able to capture every Alzheimer’s drug in development globally?
If they’re on clinicaltrials.gov, they’re in our database. But we think there’s about 15% of drugs in the world that aren’t for some reason on clinicaltrials.gov – so we know we are comprehensive, but not quite exhaustive. I’m in kind of quandary about whether to search for that other 15%. But we do always acknowledge that we’re not 100% exhaustive.
Who are the report’s main readers?
Drug developers use it for investor discussions, and also to understand the competition and the landscape. The competition might be a drug with the same mechanism, and the landscape might be drugs coming into the Alzheimer’s disease world. So if someone is developing a PDE-5 inhibitor for mild dementia, for example, they can see that other people are working on a PDE-5 inhibitor for moderate dementia, and there’s no overlap. Investors use the report to make decisions about which horse in the race to bet on. And of course it’s used by academics and clinicians to learn which are the new drugs in the pipeline, which drugs have fallen out of the pipeline, how are biomarkers changing trials, what are the new outcomes.
It’s really become a community project. Investigators will email me and say “Jeff, we’re in phase 1, make sure it’s on your map.” Or, “you forgot our agent! We’re disappointed.” When that occurs it’s because they were not in a trial on the index date – the 1 day in our publication when everything we say in the paper is true. A trial initiated 1 day later won’t make the report for that year.
What about patients and families? Are they able to use the report as well?
One of the things we want to expand with the new database is its usefulness for patients. Among the new data display approaches that we have is a world map where you can go click on a dot near your home and find active trials. That’s something patients and families want to know, right? There’s 140 drugs in clinical trials, there must be one for me, how would I get to it? Soon we will have quite a good public portal so if you want to go in and see what new monoclonal antibodies are in phase 2, you can do that with drop-down menus. It’s a very easy to use site that anyone can explore.
Looking back at your last decade tracking drugs, what are some lessons learned and what are some of the more exciting drug categories to emerge?
My answer to this question is: Biologics rule. The main successes have been in biologics, in the monoclonal antibodies against amyloid, like the two FDA-approved agents lecanemab and aducanumab. But I think that the monoclonals, while I’m really happy to have them, are a first step. If you look back at tacrine, the first drug approved in 1993 for Alzheimer’s disease, it was a very difficult drug with lots of side effects. But then within 3 years we had donepezil, which was a very benign drug. I feel that a similar evolution is likely with regard to these antibodies. The first ones, we know, have big challenges, and you learn from those challenges and you just keep improving them. But you have to start somewhere, and you have to validate that target. Now I think that amyloid is validated.
What other approaches are interesting to you?
We have seen dramatic imaging results with marked reductions in neurofibrillary tangles from an antisense oligonucleotide aimed at tau protein. And there are two very active areas in the pipeline: inflammation and synaptic plasticity. Each has roughly 20 drugs apiece in development across all phases. And as you know, both synaptic plasticity and inflammation are represented across neurodegenerative conditions.
Your annual report has always focused on drugs to treat Alzheimer’s disease. Will the new database cover other types of dementia and neurodegenerative diseases?
That’s an obvious next step. I’m hoping that late this year we will have funding to expand the database into frontotemporal lobar degenerations, which will include all the tauopathies. And there’s also an overlap with TDP-43 diseases, so we’ll bring all of that in too. We have a new initiative on Parkinson’s disease and dementia with Lewy bodies that I hope will materialize by next year. My goal is that this will eventually become a neurodegenerative disease therapies database. The really interesting drugs right now are being tested in more than one neurodegenerative disease, and we should look at those more carefully. It will be more feasible to do that if they’re on the same data set.
What about other therapy classes?
We aim to be more serious about devices.
What will you call the database?
The Clinical Trial Observatory. We may start by calling it the Alzheimer’s Disease Clinical Trial Observatory. But the intention, obviously, is to go way beyond Alzheimer’s disease. The database is managed by a terrific team of data scientists at Cleveland Clinic, led by Feixiong Cheng, PhD.
The annual pipeline report is very much associated with you. Is the database going to be different?
Right now, I’m like the grandfather of this project. I won’t be around forever. This will have to pass on, and we’re already talking about succession. We’re thinking about how to make sure this community resource continues to be a community resource. Also, over all these years the annual report reflected my perspective. But with a database, many more people will be able to share their perspectives. I happen to think that “biologics rule,” but others might look at the data, see different scientific currents, and draw different conclusions. That will create a rich dialogue.
Do you think your reports have changed people’s perspectives on Alzheimer’s disease therapies? There’s a widely held idea that the field is exclusively focused on amyloid, or even dead-ended, but the papers seem to show something different.
We think this effort has helped, and will continue to help and foster investment and growth in treatments for our patients. It really does show how diverse the clinical trials landscape is now. People are surprised to learn of the number and diversity of approaches. Just last week I was presenting at the Center for Brain Health in Dallas and there was a doctor in the audience who was a caregiver to his wife with Alzheimer’s disease. He came up afterwards and said, “I had no idea there were so many drugs in clinical trials,” because there’s no way to find out if you don’t know about this resource.
Dr. Cummings discloses consulting for a range of companies working in Alzheimer’s therapies and diagnostics, including Acadia, Alkahest, AlphaCognition, AriBio, Avanir, Axsome, Behren, Biogen, Biohaven, Cassava, Cerecin, Cortexyme, Diadem, EIP Pharma, Eisai, GemVax, Genentech, Green Valley, Grifols, Janssen, LSP, Merck, NervGen, Novo Nordisk, Oligomerix, Ono, Otsuka, PRODEO, ReMYND, Renew, Resverlogix, Roche, Signant Health, Suven, United Neuroscience, and Unlearn AI. He has received several grants from the National Institute on Aging.
A new chapter for research on treating Huntington’s disease
The past decade has been a contradictory one for research on Huntington’s disease, marked by breakthroughs in the biology and genetics of this fatal neurodegenerative disease and painful disappointments in trials of novel therapies.
What is Huntington’s disease?
Huntington’s disease is caused by a trinucleotide repeat mutation in the huntingtin gene (HTT) and follows an autosomal dominant pattern of inheritance. In people with more than 39 copies of this CAG repeat tract expansion, the HTT protein misfolds to become toxic, with more repeats linked to earlier disease onset and a more severe course.
Huntington’s disease causes loss of neurons in the striatum and disrupts the cortical-striatal-thalamic pathway, a brain circuit that governs movement. Although behavioral symptoms can emerge earlier, signature symptoms – chorea, dystonia, and cognitive abnormalities – usually present at midlife and progress until the patient’s death.
Huntington’s disease affects an estimated 30,000 people in the United States, and an estimated 10-12 people for every 100,000 worldwide – making it rare enough that neurologists who do not specialize in movement disorders might never treat a Huntington’s patient. Yet Huntington’s disease is sufficiently prevalent to attract robust research interest and sustain large registries, which have led to remarkable findings with implications not just for Huntington’s disease but for other diseases as well.
Right now, the only Food and Drug Administration–approved treatments for Huntington’s disease are symptomatic therapies to help temper disturbances of movement, sleep, and emotions. There are two major avenues of investigation into Huntington’s disease modification:
Reduce levels of mutant HTT protein, whether through small molecules, gene therapies, or antisense oligonucleotides (ASOs) that modulate RNA processing. In March 2021, Roche announced the suspension of its phase 3 trial of tominersen, an ASO.1 Trials of other protein-lowering agents were canceled for lack of target engagement or over safety concerns, in 2021 and 2022, although this approach is still considered viable.
Modify the length of CAG repeats, which involves a more recently encountered mechanism in Huntington’s disease. The strategy is at the preclinical stage. In 2015, a group of scientists reported the game-changing discovery that a large number of genes, associated with some of the same DNA-mismatch repair pathways implicated in cancer, can modify the length of CAG repeats in cells. This gave rise to a new set of therapeutic targets, now being explored.
Neurology Reviews 2023 Rare Neurological Disease Special Report spoke with two frequently collaborating researchers at the forefront of Huntington’s disease science – Cristina Sampaio, MD, PhD, chief medical officer of CHDI Management, Princeton, N.J., and Sarah Tabrizi, MD, PhD, from University College London – about lessons learned from the past several years of Huntington’s disease drug research.
The CHDI Foundation, a nonprofit research organization, was founded in 2003 to facilitate development of Huntington’s disease therapies. Its clinical research platform, Enroll-HD, includes a global registry of some 28,000 patients and a biobank to facilitate biomarker discovery and validation. Dr. Tabrizi’s lab explores Huntington’s disease drug targets in both HTT and DNA mismatch repair, and led two CHDI-funded observational studies, TRACK-HD and TrackOn-HD, to characterize disease progression in people with Huntington’s disease. In 2022, Dr. Tabrizi and Dr. Sampaio were coauthors of a comprehensive review of Huntington’s disease drug development and published a new disease-staging system to help enable trials in presymptomatic Huntington’s disease.
“The story of Huntington’s therapeutics is very informative,” Dr. Sampaio said. “Understanding these mechanisms is relevant for any neurologist – not only for Huntington’s but because they represent a prototype development for a big group of therapies and make us better equipped to think about everything else that is happening in neurology. They’re giving us an understanding of where neurology is going.”
Tackling a tricky protein
Most Huntington’s disease research has focused on ways to attack or lower mutant HTT protein. But HTT has proven a tricky target: HTT is a large protein, present in all cells, and known to interact with more than 100 genes. Healthy HTT is critical to fetal development, but its functions in the adult body remain something of a mystery. Almost all people with Huntington’s disease have both wild-type and mutant HTT.
Tominersen, the investigative ASO developed by Roche, works to block translation of the HTT message, leading to a reduction in both healthy and mutant HTT protein. It is delivered by lumbar injection to reach the brain. Upon halting its phase 3 trial of tominersen in 2021, Roche reported that people in the high-dosage treatment group did measurably worse – although it remains unclear whether this was caused by excess protein lowering or an off-target effect. The tominersen program was the first to clearly show that it is possible to lower HTT with an intervention – a critical first step in the development of this class of drugs.
“I think the problem with the trial was the aggressive loading doses plus exposure-related toxicity,” Dr. Tabrizi said. “Whether that exposure-related toxicity was related to too much wild-type HTT lowering or the proinflammatory effects of the ASO, you can’t yet disentangle.” Roche has not given up: The company is now seeking to test lower dosages of tominersen on a younger subgroup of patients who have fewer CAG repeats, in whom a benefit of protein lowering might be more clearly seen.
Small molecules and gene therapies have also been developed to reduce mutant HTT, although most, as is the case with tominersen, will also reduce healthy protein.
“There is a long and complex debate about how much [lowering] is too much and how much is enough,” Dr. Sampaio said. “And this is a problem that has not been solved.”
Allele-specific therapy. A different class of investigative drugs, called allele-specific therapies, target only mutant HTT, sparing healthy protein. The drugs are tailored to genetic markers, or single-nucleotide polymorphisms (SNPs), that are present in different Huntington’s disease populations worldwide. Because treatments based on SNPs are highly tailored, “you need a new drug for each SNP to cover the global Huntington’s disease population,” Dr. Sampaio said. “This presents challenges from a regulatory perspective, as each drug would have to be evaluated separately.”
Two SNP-based therapies failed clinical trials in 2021, when they did not engage their targets.2 A third trial succeeded in lowering mutant HTT while preserving healthy protein and is being evaluated further in the clinic.2
Other strategies have yielded disappointing or mixed results:
A trial of branaplam, a small molecule, was stopped late in 2022 after patients developed peripheral neuropathy.3 Novartis, the drug’s manufacturer, said it would no longer investigate branaplam for Huntington’s disease.
Months earlier, in August 2022, a trial of a gene therapy to lower HTT protein – injected directly into the striatum of the brain – was halted because of adverse events in its high-dosage arm but has since resumed, with some changes to protocol.4
In neither case was excess protein-lowering thought to be the cause of safety problems.
DNA repair emerges as a promising target
Scientists have understood, since the 1990s, that the number of excess CAG repeats measured in a blood test is not the sole predictor of the onset of motor symptoms or rate of progression of Huntington’s disease.
Since the early 2000s, researchers have also known that the number of CAG repeats in cells is unstable, both in different tissues and cell types, and over time. People with Huntington’s disease turned out to be genetic mosaics, with varying, changing lengths of CAG repeats in cells. Repeats increase as a person ages, most drastically in the spiny medium neurons of the brain.
The process by which CAG repetitions grow in cells, known as somatic instability, remained poorly understood and little investigated until 2015, when a genomewide association study revealed previously unknown mechanisms.5 As it turns out, genes involved in the growth of CAG repeats are related to the DNA mismatch repair pathway, which is also important in cancer.
DNA mismatch repair refers to a complex housekeeping system, involving multiple genes and enzymes, that is fundamental to the functioning of the body as genes are continuously being translated to form proteins. Mismatch repair becomes increasingly error-prone with age: Mistakes that are not repaired become mutations, some of which are irrelevant and others that can be deleterious and lead to cancer.
In Huntington’s disease, enzymes involved in repairing DNA are the same ones that can erroneously add CAG repeats to HTT. A person with Huntington’s disease inherits what can be considered a “dyslexic” DNA repair system, Dr. Sampaio said, that misreads its template and keeps adding CAGs.
After the 2015 genomewide association study, “the DNA mismatch repair pathway became hugely important in Huntington’s disease research, and there is a lot of attention being paid now to its components. The idea is that, if we can intervene in this process, we might stop the somatic instability, the growing of the CAG repetitions, and ameliorate the progression of the disease,” Dr. Sampaio said.
In 2017 Dr. Tabrizi’s team reported that the mismatch repair gene MSH-3 was as a key driver of CAG repeats in people with Huntington’s disease.6 “I’m working really closely now with DNA repair scientists who’ve been working in cancer for 20 years. Cancer and repeat expansion diseases have really come together,” Dr. Tabrizi said.
At CHDI’s April 2023 therapeutics conference in Dubrovnik, Croatia, scientists presented findings on how to target MSH-3 and other mechanisms that underlie somatic instability.7 (Several drug companies are working on small molecules, ASOs, and other ways to inhibit MSH-3.) Researchers also presented extensively on protein lowering. The two treatment strategies are compatible for Huntington’s disease, Dr. Tabrizi said.
“I think the best way to approach Huntington’s is to target the somatic CAG repeat expansion by inhibiting MSH-3 in some way, and also target HTT lowering – but targeting it at the DNA level, as opposed to clearing the protein,” Dr. Tabrizi said. DNA-centered approaches in preclinical testing include CRISPR gene editing to inactivate mutant HTT and zinc finger proteins that allow selective targeting of DNA to reduce mutant HTT.
Recent findings on the mismatch repair pathway in Huntington’s disease have direct implications for other rare neurologic diseases caused by triplet repeat mutations, including myotonic dystrophy and cerebellar ataxias.
“There is very strong basic fundamental research in Huntington’s disease that doesn’t exist for every disease,” Dr. Sampaio said. “The fact that it is monogenic, and an adult disease that progresses relatively slowly, has made it a good disease to study, a kind of model.”
Huntington’s disease research has also generated research strategies of value in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s. It provided key insights about neurofilament light, a biomarker of neuronal damage, and about the ASO drug class, which is being investigated for its utility treating in a range of diseases.
Previously, Huntington’s disease trial cohorts and registries focused on patients with late symptomatic disease. However, researchers are now pivoting to patients with less-severe disease and to preclinical mutation carriers. “We now know you have to treat early,” Dr. Tabrizi said. “This has implications for the whole field.”
Dr. Sampaio disclosed that she is an employee of CHDI Management, the administrative arm of the CHDI foundation. Dr. Tabrizi disclosed serving as a consultant to Alnylam Pharmaceuticals, Annexon, Ascidian Therapeutics, Arrowhead Pharmaceuticals, Atalanta Therapeutics, Design Therapeutics, F. Hoffmann-La Roche, HCD Economics, IQVIA, Iris Medicine, Latus Bio, LifeEdit, Novartis, Pfizer, Prilenia Therapeutics, PTC Therapeutics, Rgenta Therapeutics, Takeda Pharmaceuticals, uniQure, and Vertex Pharmaceuticals.
References
1. Genentech. Genentech Provides Update on Tominersen Program in Manifest Huntington’s Disease. https://www.gene.com/media/press-releases/14902/2021-03-22/genentech-provides-update-on-tominersen-.
2. Wave Life Sciences. Defining a new era of oligonucleotides. https://ir.wavelifesciences.com/news-releases/news-release-details/wave-life-sciences-announces-positive-update-phase-1b2a-select.
3. Novartis. Community update: Status of VIBRANT-HD, the study of branaplam/LMI070 in Huntington’s disease. https://hdsa.org/wp-content/uploads/2022/08/Novartis-FINAL-Community-Letter-8-24-22.pdf.
4. UniQure. Second Quarter 2022 Financial Results. https://uniqure.gcs-web.com/node/10856/pdf.
5. Genetic Modifiers of Huntington’s Disease (GeM-HD) Consortium. Cell. 2015 Jul 30;162(3):516-26. doi: 10.1016/j.cell.2015.07.003.
6. Moss DJH et al. Lancet Neurol. 2017 Sep;16(9):701-11. doi: 10.1016/S1474-4422(17)30161-8.
7. CHDI Foundation. Postcard from Dubrovnik 2023. https://chdifoundation.org/postcard-from-dubrovnik-2023/.
The past decade has been a contradictory one for research on Huntington’s disease, marked by breakthroughs in the biology and genetics of this fatal neurodegenerative disease and painful disappointments in trials of novel therapies.
What is Huntington’s disease?
Huntington’s disease is caused by a trinucleotide repeat mutation in the huntingtin gene (HTT) and follows an autosomal dominant pattern of inheritance. In people with more than 39 copies of this CAG repeat tract expansion, the HTT protein misfolds to become toxic, with more repeats linked to earlier disease onset and a more severe course.
Huntington’s disease causes loss of neurons in the striatum and disrupts the cortical-striatal-thalamic pathway, a brain circuit that governs movement. Although behavioral symptoms can emerge earlier, signature symptoms – chorea, dystonia, and cognitive abnormalities – usually present at midlife and progress until the patient’s death.
Huntington’s disease affects an estimated 30,000 people in the United States, and an estimated 10-12 people for every 100,000 worldwide – making it rare enough that neurologists who do not specialize in movement disorders might never treat a Huntington’s patient. Yet Huntington’s disease is sufficiently prevalent to attract robust research interest and sustain large registries, which have led to remarkable findings with implications not just for Huntington’s disease but for other diseases as well.
Right now, the only Food and Drug Administration–approved treatments for Huntington’s disease are symptomatic therapies to help temper disturbances of movement, sleep, and emotions. There are two major avenues of investigation into Huntington’s disease modification:
Reduce levels of mutant HTT protein, whether through small molecules, gene therapies, or antisense oligonucleotides (ASOs) that modulate RNA processing. In March 2021, Roche announced the suspension of its phase 3 trial of tominersen, an ASO.1 Trials of other protein-lowering agents were canceled for lack of target engagement or over safety concerns, in 2021 and 2022, although this approach is still considered viable.
Modify the length of CAG repeats, which involves a more recently encountered mechanism in Huntington’s disease. The strategy is at the preclinical stage. In 2015, a group of scientists reported the game-changing discovery that a large number of genes, associated with some of the same DNA-mismatch repair pathways implicated in cancer, can modify the length of CAG repeats in cells. This gave rise to a new set of therapeutic targets, now being explored.
Neurology Reviews 2023 Rare Neurological Disease Special Report spoke with two frequently collaborating researchers at the forefront of Huntington’s disease science – Cristina Sampaio, MD, PhD, chief medical officer of CHDI Management, Princeton, N.J., and Sarah Tabrizi, MD, PhD, from University College London – about lessons learned from the past several years of Huntington’s disease drug research.
The CHDI Foundation, a nonprofit research organization, was founded in 2003 to facilitate development of Huntington’s disease therapies. Its clinical research platform, Enroll-HD, includes a global registry of some 28,000 patients and a biobank to facilitate biomarker discovery and validation. Dr. Tabrizi’s lab explores Huntington’s disease drug targets in both HTT and DNA mismatch repair, and led two CHDI-funded observational studies, TRACK-HD and TrackOn-HD, to characterize disease progression in people with Huntington’s disease. In 2022, Dr. Tabrizi and Dr. Sampaio were coauthors of a comprehensive review of Huntington’s disease drug development and published a new disease-staging system to help enable trials in presymptomatic Huntington’s disease.
“The story of Huntington’s therapeutics is very informative,” Dr. Sampaio said. “Understanding these mechanisms is relevant for any neurologist – not only for Huntington’s but because they represent a prototype development for a big group of therapies and make us better equipped to think about everything else that is happening in neurology. They’re giving us an understanding of where neurology is going.”
Tackling a tricky protein
Most Huntington’s disease research has focused on ways to attack or lower mutant HTT protein. But HTT has proven a tricky target: HTT is a large protein, present in all cells, and known to interact with more than 100 genes. Healthy HTT is critical to fetal development, but its functions in the adult body remain something of a mystery. Almost all people with Huntington’s disease have both wild-type and mutant HTT.
Tominersen, the investigative ASO developed by Roche, works to block translation of the HTT message, leading to a reduction in both healthy and mutant HTT protein. It is delivered by lumbar injection to reach the brain. Upon halting its phase 3 trial of tominersen in 2021, Roche reported that people in the high-dosage treatment group did measurably worse – although it remains unclear whether this was caused by excess protein lowering or an off-target effect. The tominersen program was the first to clearly show that it is possible to lower HTT with an intervention – a critical first step in the development of this class of drugs.
“I think the problem with the trial was the aggressive loading doses plus exposure-related toxicity,” Dr. Tabrizi said. “Whether that exposure-related toxicity was related to too much wild-type HTT lowering or the proinflammatory effects of the ASO, you can’t yet disentangle.” Roche has not given up: The company is now seeking to test lower dosages of tominersen on a younger subgroup of patients who have fewer CAG repeats, in whom a benefit of protein lowering might be more clearly seen.
Small molecules and gene therapies have also been developed to reduce mutant HTT, although most, as is the case with tominersen, will also reduce healthy protein.
“There is a long and complex debate about how much [lowering] is too much and how much is enough,” Dr. Sampaio said. “And this is a problem that has not been solved.”
Allele-specific therapy. A different class of investigative drugs, called allele-specific therapies, target only mutant HTT, sparing healthy protein. The drugs are tailored to genetic markers, or single-nucleotide polymorphisms (SNPs), that are present in different Huntington’s disease populations worldwide. Because treatments based on SNPs are highly tailored, “you need a new drug for each SNP to cover the global Huntington’s disease population,” Dr. Sampaio said. “This presents challenges from a regulatory perspective, as each drug would have to be evaluated separately.”
Two SNP-based therapies failed clinical trials in 2021, when they did not engage their targets.2 A third trial succeeded in lowering mutant HTT while preserving healthy protein and is being evaluated further in the clinic.2
Other strategies have yielded disappointing or mixed results:
A trial of branaplam, a small molecule, was stopped late in 2022 after patients developed peripheral neuropathy.3 Novartis, the drug’s manufacturer, said it would no longer investigate branaplam for Huntington’s disease.
Months earlier, in August 2022, a trial of a gene therapy to lower HTT protein – injected directly into the striatum of the brain – was halted because of adverse events in its high-dosage arm but has since resumed, with some changes to protocol.4
In neither case was excess protein-lowering thought to be the cause of safety problems.
DNA repair emerges as a promising target
Scientists have understood, since the 1990s, that the number of excess CAG repeats measured in a blood test is not the sole predictor of the onset of motor symptoms or rate of progression of Huntington’s disease.
Since the early 2000s, researchers have also known that the number of CAG repeats in cells is unstable, both in different tissues and cell types, and over time. People with Huntington’s disease turned out to be genetic mosaics, with varying, changing lengths of CAG repeats in cells. Repeats increase as a person ages, most drastically in the spiny medium neurons of the brain.
The process by which CAG repetitions grow in cells, known as somatic instability, remained poorly understood and little investigated until 2015, when a genomewide association study revealed previously unknown mechanisms.5 As it turns out, genes involved in the growth of CAG repeats are related to the DNA mismatch repair pathway, which is also important in cancer.
DNA mismatch repair refers to a complex housekeeping system, involving multiple genes and enzymes, that is fundamental to the functioning of the body as genes are continuously being translated to form proteins. Mismatch repair becomes increasingly error-prone with age: Mistakes that are not repaired become mutations, some of which are irrelevant and others that can be deleterious and lead to cancer.
In Huntington’s disease, enzymes involved in repairing DNA are the same ones that can erroneously add CAG repeats to HTT. A person with Huntington’s disease inherits what can be considered a “dyslexic” DNA repair system, Dr. Sampaio said, that misreads its template and keeps adding CAGs.
After the 2015 genomewide association study, “the DNA mismatch repair pathway became hugely important in Huntington’s disease research, and there is a lot of attention being paid now to its components. The idea is that, if we can intervene in this process, we might stop the somatic instability, the growing of the CAG repetitions, and ameliorate the progression of the disease,” Dr. Sampaio said.
In 2017 Dr. Tabrizi’s team reported that the mismatch repair gene MSH-3 was as a key driver of CAG repeats in people with Huntington’s disease.6 “I’m working really closely now with DNA repair scientists who’ve been working in cancer for 20 years. Cancer and repeat expansion diseases have really come together,” Dr. Tabrizi said.
At CHDI’s April 2023 therapeutics conference in Dubrovnik, Croatia, scientists presented findings on how to target MSH-3 and other mechanisms that underlie somatic instability.7 (Several drug companies are working on small molecules, ASOs, and other ways to inhibit MSH-3.) Researchers also presented extensively on protein lowering. The two treatment strategies are compatible for Huntington’s disease, Dr. Tabrizi said.
“I think the best way to approach Huntington’s is to target the somatic CAG repeat expansion by inhibiting MSH-3 in some way, and also target HTT lowering – but targeting it at the DNA level, as opposed to clearing the protein,” Dr. Tabrizi said. DNA-centered approaches in preclinical testing include CRISPR gene editing to inactivate mutant HTT and zinc finger proteins that allow selective targeting of DNA to reduce mutant HTT.
Recent findings on the mismatch repair pathway in Huntington’s disease have direct implications for other rare neurologic diseases caused by triplet repeat mutations, including myotonic dystrophy and cerebellar ataxias.
“There is very strong basic fundamental research in Huntington’s disease that doesn’t exist for every disease,” Dr. Sampaio said. “The fact that it is monogenic, and an adult disease that progresses relatively slowly, has made it a good disease to study, a kind of model.”
Huntington’s disease research has also generated research strategies of value in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s. It provided key insights about neurofilament light, a biomarker of neuronal damage, and about the ASO drug class, which is being investigated for its utility treating in a range of diseases.
Previously, Huntington’s disease trial cohorts and registries focused on patients with late symptomatic disease. However, researchers are now pivoting to patients with less-severe disease and to preclinical mutation carriers. “We now know you have to treat early,” Dr. Tabrizi said. “This has implications for the whole field.”
Dr. Sampaio disclosed that she is an employee of CHDI Management, the administrative arm of the CHDI foundation. Dr. Tabrizi disclosed serving as a consultant to Alnylam Pharmaceuticals, Annexon, Ascidian Therapeutics, Arrowhead Pharmaceuticals, Atalanta Therapeutics, Design Therapeutics, F. Hoffmann-La Roche, HCD Economics, IQVIA, Iris Medicine, Latus Bio, LifeEdit, Novartis, Pfizer, Prilenia Therapeutics, PTC Therapeutics, Rgenta Therapeutics, Takeda Pharmaceuticals, uniQure, and Vertex Pharmaceuticals.
References
1. Genentech. Genentech Provides Update on Tominersen Program in Manifest Huntington’s Disease. https://www.gene.com/media/press-releases/14902/2021-03-22/genentech-provides-update-on-tominersen-.
2. Wave Life Sciences. Defining a new era of oligonucleotides. https://ir.wavelifesciences.com/news-releases/news-release-details/wave-life-sciences-announces-positive-update-phase-1b2a-select.
3. Novartis. Community update: Status of VIBRANT-HD, the study of branaplam/LMI070 in Huntington’s disease. https://hdsa.org/wp-content/uploads/2022/08/Novartis-FINAL-Community-Letter-8-24-22.pdf.
4. UniQure. Second Quarter 2022 Financial Results. https://uniqure.gcs-web.com/node/10856/pdf.
5. Genetic Modifiers of Huntington’s Disease (GeM-HD) Consortium. Cell. 2015 Jul 30;162(3):516-26. doi: 10.1016/j.cell.2015.07.003.
6. Moss DJH et al. Lancet Neurol. 2017 Sep;16(9):701-11. doi: 10.1016/S1474-4422(17)30161-8.
7. CHDI Foundation. Postcard from Dubrovnik 2023. https://chdifoundation.org/postcard-from-dubrovnik-2023/.
The past decade has been a contradictory one for research on Huntington’s disease, marked by breakthroughs in the biology and genetics of this fatal neurodegenerative disease and painful disappointments in trials of novel therapies.
What is Huntington’s disease?
Huntington’s disease is caused by a trinucleotide repeat mutation in the huntingtin gene (HTT) and follows an autosomal dominant pattern of inheritance. In people with more than 39 copies of this CAG repeat tract expansion, the HTT protein misfolds to become toxic, with more repeats linked to earlier disease onset and a more severe course.
Huntington’s disease causes loss of neurons in the striatum and disrupts the cortical-striatal-thalamic pathway, a brain circuit that governs movement. Although behavioral symptoms can emerge earlier, signature symptoms – chorea, dystonia, and cognitive abnormalities – usually present at midlife and progress until the patient’s death.
Huntington’s disease affects an estimated 30,000 people in the United States, and an estimated 10-12 people for every 100,000 worldwide – making it rare enough that neurologists who do not specialize in movement disorders might never treat a Huntington’s patient. Yet Huntington’s disease is sufficiently prevalent to attract robust research interest and sustain large registries, which have led to remarkable findings with implications not just for Huntington’s disease but for other diseases as well.
Right now, the only Food and Drug Administration–approved treatments for Huntington’s disease are symptomatic therapies to help temper disturbances of movement, sleep, and emotions. There are two major avenues of investigation into Huntington’s disease modification:
Reduce levels of mutant HTT protein, whether through small molecules, gene therapies, or antisense oligonucleotides (ASOs) that modulate RNA processing. In March 2021, Roche announced the suspension of its phase 3 trial of tominersen, an ASO.1 Trials of other protein-lowering agents were canceled for lack of target engagement or over safety concerns, in 2021 and 2022, although this approach is still considered viable.
Modify the length of CAG repeats, which involves a more recently encountered mechanism in Huntington’s disease. The strategy is at the preclinical stage. In 2015, a group of scientists reported the game-changing discovery that a large number of genes, associated with some of the same DNA-mismatch repair pathways implicated in cancer, can modify the length of CAG repeats in cells. This gave rise to a new set of therapeutic targets, now being explored.
Neurology Reviews 2023 Rare Neurological Disease Special Report spoke with two frequently collaborating researchers at the forefront of Huntington’s disease science – Cristina Sampaio, MD, PhD, chief medical officer of CHDI Management, Princeton, N.J., and Sarah Tabrizi, MD, PhD, from University College London – about lessons learned from the past several years of Huntington’s disease drug research.
The CHDI Foundation, a nonprofit research organization, was founded in 2003 to facilitate development of Huntington’s disease therapies. Its clinical research platform, Enroll-HD, includes a global registry of some 28,000 patients and a biobank to facilitate biomarker discovery and validation. Dr. Tabrizi’s lab explores Huntington’s disease drug targets in both HTT and DNA mismatch repair, and led two CHDI-funded observational studies, TRACK-HD and TrackOn-HD, to characterize disease progression in people with Huntington’s disease. In 2022, Dr. Tabrizi and Dr. Sampaio were coauthors of a comprehensive review of Huntington’s disease drug development and published a new disease-staging system to help enable trials in presymptomatic Huntington’s disease.
“The story of Huntington’s therapeutics is very informative,” Dr. Sampaio said. “Understanding these mechanisms is relevant for any neurologist – not only for Huntington’s but because they represent a prototype development for a big group of therapies and make us better equipped to think about everything else that is happening in neurology. They’re giving us an understanding of where neurology is going.”
Tackling a tricky protein
Most Huntington’s disease research has focused on ways to attack or lower mutant HTT protein. But HTT has proven a tricky target: HTT is a large protein, present in all cells, and known to interact with more than 100 genes. Healthy HTT is critical to fetal development, but its functions in the adult body remain something of a mystery. Almost all people with Huntington’s disease have both wild-type and mutant HTT.
Tominersen, the investigative ASO developed by Roche, works to block translation of the HTT message, leading to a reduction in both healthy and mutant HTT protein. It is delivered by lumbar injection to reach the brain. Upon halting its phase 3 trial of tominersen in 2021, Roche reported that people in the high-dosage treatment group did measurably worse – although it remains unclear whether this was caused by excess protein lowering or an off-target effect. The tominersen program was the first to clearly show that it is possible to lower HTT with an intervention – a critical first step in the development of this class of drugs.
“I think the problem with the trial was the aggressive loading doses plus exposure-related toxicity,” Dr. Tabrizi said. “Whether that exposure-related toxicity was related to too much wild-type HTT lowering or the proinflammatory effects of the ASO, you can’t yet disentangle.” Roche has not given up: The company is now seeking to test lower dosages of tominersen on a younger subgroup of patients who have fewer CAG repeats, in whom a benefit of protein lowering might be more clearly seen.
Small molecules and gene therapies have also been developed to reduce mutant HTT, although most, as is the case with tominersen, will also reduce healthy protein.
“There is a long and complex debate about how much [lowering] is too much and how much is enough,” Dr. Sampaio said. “And this is a problem that has not been solved.”
Allele-specific therapy. A different class of investigative drugs, called allele-specific therapies, target only mutant HTT, sparing healthy protein. The drugs are tailored to genetic markers, or single-nucleotide polymorphisms (SNPs), that are present in different Huntington’s disease populations worldwide. Because treatments based on SNPs are highly tailored, “you need a new drug for each SNP to cover the global Huntington’s disease population,” Dr. Sampaio said. “This presents challenges from a regulatory perspective, as each drug would have to be evaluated separately.”
Two SNP-based therapies failed clinical trials in 2021, when they did not engage their targets.2 A third trial succeeded in lowering mutant HTT while preserving healthy protein and is being evaluated further in the clinic.2
Other strategies have yielded disappointing or mixed results:
A trial of branaplam, a small molecule, was stopped late in 2022 after patients developed peripheral neuropathy.3 Novartis, the drug’s manufacturer, said it would no longer investigate branaplam for Huntington’s disease.
Months earlier, in August 2022, a trial of a gene therapy to lower HTT protein – injected directly into the striatum of the brain – was halted because of adverse events in its high-dosage arm but has since resumed, with some changes to protocol.4
In neither case was excess protein-lowering thought to be the cause of safety problems.
DNA repair emerges as a promising target
Scientists have understood, since the 1990s, that the number of excess CAG repeats measured in a blood test is not the sole predictor of the onset of motor symptoms or rate of progression of Huntington’s disease.
Since the early 2000s, researchers have also known that the number of CAG repeats in cells is unstable, both in different tissues and cell types, and over time. People with Huntington’s disease turned out to be genetic mosaics, with varying, changing lengths of CAG repeats in cells. Repeats increase as a person ages, most drastically in the spiny medium neurons of the brain.
The process by which CAG repetitions grow in cells, known as somatic instability, remained poorly understood and little investigated until 2015, when a genomewide association study revealed previously unknown mechanisms.5 As it turns out, genes involved in the growth of CAG repeats are related to the DNA mismatch repair pathway, which is also important in cancer.
DNA mismatch repair refers to a complex housekeeping system, involving multiple genes and enzymes, that is fundamental to the functioning of the body as genes are continuously being translated to form proteins. Mismatch repair becomes increasingly error-prone with age: Mistakes that are not repaired become mutations, some of which are irrelevant and others that can be deleterious and lead to cancer.
In Huntington’s disease, enzymes involved in repairing DNA are the same ones that can erroneously add CAG repeats to HTT. A person with Huntington’s disease inherits what can be considered a “dyslexic” DNA repair system, Dr. Sampaio said, that misreads its template and keeps adding CAGs.
After the 2015 genomewide association study, “the DNA mismatch repair pathway became hugely important in Huntington’s disease research, and there is a lot of attention being paid now to its components. The idea is that, if we can intervene in this process, we might stop the somatic instability, the growing of the CAG repetitions, and ameliorate the progression of the disease,” Dr. Sampaio said.
In 2017 Dr. Tabrizi’s team reported that the mismatch repair gene MSH-3 was as a key driver of CAG repeats in people with Huntington’s disease.6 “I’m working really closely now with DNA repair scientists who’ve been working in cancer for 20 years. Cancer and repeat expansion diseases have really come together,” Dr. Tabrizi said.
At CHDI’s April 2023 therapeutics conference in Dubrovnik, Croatia, scientists presented findings on how to target MSH-3 and other mechanisms that underlie somatic instability.7 (Several drug companies are working on small molecules, ASOs, and other ways to inhibit MSH-3.) Researchers also presented extensively on protein lowering. The two treatment strategies are compatible for Huntington’s disease, Dr. Tabrizi said.
“I think the best way to approach Huntington’s is to target the somatic CAG repeat expansion by inhibiting MSH-3 in some way, and also target HTT lowering – but targeting it at the DNA level, as opposed to clearing the protein,” Dr. Tabrizi said. DNA-centered approaches in preclinical testing include CRISPR gene editing to inactivate mutant HTT and zinc finger proteins that allow selective targeting of DNA to reduce mutant HTT.
Recent findings on the mismatch repair pathway in Huntington’s disease have direct implications for other rare neurologic diseases caused by triplet repeat mutations, including myotonic dystrophy and cerebellar ataxias.
“There is very strong basic fundamental research in Huntington’s disease that doesn’t exist for every disease,” Dr. Sampaio said. “The fact that it is monogenic, and an adult disease that progresses relatively slowly, has made it a good disease to study, a kind of model.”
Huntington’s disease research has also generated research strategies of value in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s. It provided key insights about neurofilament light, a biomarker of neuronal damage, and about the ASO drug class, which is being investigated for its utility treating in a range of diseases.
Previously, Huntington’s disease trial cohorts and registries focused on patients with late symptomatic disease. However, researchers are now pivoting to patients with less-severe disease and to preclinical mutation carriers. “We now know you have to treat early,” Dr. Tabrizi said. “This has implications for the whole field.”
Dr. Sampaio disclosed that she is an employee of CHDI Management, the administrative arm of the CHDI foundation. Dr. Tabrizi disclosed serving as a consultant to Alnylam Pharmaceuticals, Annexon, Ascidian Therapeutics, Arrowhead Pharmaceuticals, Atalanta Therapeutics, Design Therapeutics, F. Hoffmann-La Roche, HCD Economics, IQVIA, Iris Medicine, Latus Bio, LifeEdit, Novartis, Pfizer, Prilenia Therapeutics, PTC Therapeutics, Rgenta Therapeutics, Takeda Pharmaceuticals, uniQure, and Vertex Pharmaceuticals.
References
1. Genentech. Genentech Provides Update on Tominersen Program in Manifest Huntington’s Disease. https://www.gene.com/media/press-releases/14902/2021-03-22/genentech-provides-update-on-tominersen-.
2. Wave Life Sciences. Defining a new era of oligonucleotides. https://ir.wavelifesciences.com/news-releases/news-release-details/wave-life-sciences-announces-positive-update-phase-1b2a-select.
3. Novartis. Community update: Status of VIBRANT-HD, the study of branaplam/LMI070 in Huntington’s disease. https://hdsa.org/wp-content/uploads/2022/08/Novartis-FINAL-Community-Letter-8-24-22.pdf.
4. UniQure. Second Quarter 2022 Financial Results. https://uniqure.gcs-web.com/node/10856/pdf.
5. Genetic Modifiers of Huntington’s Disease (GeM-HD) Consortium. Cell. 2015 Jul 30;162(3):516-26. doi: 10.1016/j.cell.2015.07.003.
6. Moss DJH et al. Lancet Neurol. 2017 Sep;16(9):701-11. doi: 10.1016/S1474-4422(17)30161-8.
7. CHDI Foundation. Postcard from Dubrovnik 2023. https://chdifoundation.org/postcard-from-dubrovnik-2023/.
AGA CPU stresses brain-gut aspects of bloating, distention and belching
A new Clinical Practice Update from the AGA on belching, abdominal bloating, and distention offers practical management strategies for a class of disorders that, while highly prevalent, can be confusing to clinicians because of their nonspecific and overlapping symptomatology and wide range of possible causes.
The expert review, published online in Gastroenterology, is dedicated to these specific disorders, which, when not caused by bacteria, food intolerance, or autoimmune disease, are increasingly viewed as stemming from dysregulation of the brain-gut axis, and therefore responsive to interventions such as biofeedback therapy and central nervous system modulators, including antidepressants referred to as neuromodulators due to their pain modulating effects in the gut.
Baharak Moshiree, MD, of Atrium Health, Wake Forest Medical University, Charlotte, N.C., the lead author, said the guidance is aimed at GI specialists as much as primary care physicians and other providers who treat patients with these disorders.
Clinicians may not always know which diagnostic studies to order for a patient with bloating, distention, or belching, Dr. Moshiree said, and since large randomized controlled trials in these patient groups are not available, making evidence-based treatment recommendations is challenging. Because the disorders are ubiquitous, “there’s a lot of social media attention around them, and these include fad diets and drugs labeled as medical foods, like probiotics, that patients will often try.”
The guidance includes 15 best practice advice statements along with two diagnostic and treatment algorithms, one for belching and the other for bloating and distention.
For belching, the authors stress discerning between gastric and supragastric belching using clinical history and examination, and if needed, impedance Ph monitoring. For supragastric belching, or esophageal belching, treatment considerations may include cognitive behavioral therapy, biofeedback training, and neuromodulator (antidepressant) drugs either alone or combined with psychological therapies.
Abdominal bloating and distention should be diagnosed using the Rome IV criteria, and in patients with suspected carbohydrate enzyme deficiencies, dietary restriction of potentially problematic carbohydrates or breath testing may be used to rule out intolerance. In a subset of at-risk patients, “small bowel aspiration and glucose- or lactulose-based hydrogen breath testing may be used to evaluate for small intestinal bacterial overgrowth,” the guidance says. Blood testing may be used to rule out celiac disease, and, if positive, a definitive diagnosis should be confirmed with small bowel tissue biopsy obtained during an upper endoscopy, Dr. Moshiree and her colleagues wrote.
Endoscopy and imaging should be restricted to patients with alarm features such as vomiting or weight loss, rapid worsening of symptoms, or an abnormal physical exam. Tests such as gastric emptying transit studies should not be routinely ordered unless nausea and vomiting are present. Similarly, whole-gut motility studies should be ordered only if there are symptoms suggestive of motility disorders, with testing carried out at specialized centers.
When constipation occurs with bloating, clinicians should use anorectal physiology testing to rule out a pelvic-floor disorder, which, if present, can be treated with pelvic floor biofeedback training. Constipation in the context of bloating may also be treated with laxatives. Probiotics are not advised as treatment for bloating and distention in this guidance, given a lack of robust studies. However, neuromodulators may help reduce visceral or gut hypersensitivity and improve psychological comorbidities if these are present, the authors wrote.
Conditions treated with dietary modifications should be overseen by dietitians, and diaphragmatic breathing and neuromodulators can be used to treat a condition called abdominophrenic dyssynergia, the guidance says.
“We tried to make it clinically useful,” Dr. Moshiree said of the practice update, which was not the result of systematic reviews or meta-analyses of multicenter randomized controlled trials. The update contains no ratings on its recommendations and does not grade the evidence used. Rather, the three coauthors looked to results from published randomized trials and observational studies, along with their own expert opinion.
For example, the guidance’s best practice advice on abdominophrenic dyssynergia came from single center studies in Italy where bloating improved with use of biofeedback therapy for this condition. Although this was a single center study, experts have found that biofeedback therapy is helpful for relaxing the pelvic floor muscles which can help bloating and distension symptoms.
Dr. Moshiree also pointed to a 2021 narrative review by Brian E. Lacy, MD. and David Cangemi, MD, of the Mayo Clinic in Jacksonville, Fla., that helped inform the framework for this clinical practice update.
Dr. Moshiree disclosed financial relationships with several pharmaceutical companies including Salix, AbbVie, Medtronic, and Takeda. Her two coauthors, Douglas Drossman, MD, of the Rome Foundation and the University of North Carolina, Chapel Hill, and Aasma Shaukat, MD, of New York University, also disclosed industry support.
A new Clinical Practice Update from the AGA on belching, abdominal bloating, and distention offers practical management strategies for a class of disorders that, while highly prevalent, can be confusing to clinicians because of their nonspecific and overlapping symptomatology and wide range of possible causes.
The expert review, published online in Gastroenterology, is dedicated to these specific disorders, which, when not caused by bacteria, food intolerance, or autoimmune disease, are increasingly viewed as stemming from dysregulation of the brain-gut axis, and therefore responsive to interventions such as biofeedback therapy and central nervous system modulators, including antidepressants referred to as neuromodulators due to their pain modulating effects in the gut.
Baharak Moshiree, MD, of Atrium Health, Wake Forest Medical University, Charlotte, N.C., the lead author, said the guidance is aimed at GI specialists as much as primary care physicians and other providers who treat patients with these disorders.
Clinicians may not always know which diagnostic studies to order for a patient with bloating, distention, or belching, Dr. Moshiree said, and since large randomized controlled trials in these patient groups are not available, making evidence-based treatment recommendations is challenging. Because the disorders are ubiquitous, “there’s a lot of social media attention around them, and these include fad diets and drugs labeled as medical foods, like probiotics, that patients will often try.”
The guidance includes 15 best practice advice statements along with two diagnostic and treatment algorithms, one for belching and the other for bloating and distention.
For belching, the authors stress discerning between gastric and supragastric belching using clinical history and examination, and if needed, impedance Ph monitoring. For supragastric belching, or esophageal belching, treatment considerations may include cognitive behavioral therapy, biofeedback training, and neuromodulator (antidepressant) drugs either alone or combined with psychological therapies.
Abdominal bloating and distention should be diagnosed using the Rome IV criteria, and in patients with suspected carbohydrate enzyme deficiencies, dietary restriction of potentially problematic carbohydrates or breath testing may be used to rule out intolerance. In a subset of at-risk patients, “small bowel aspiration and glucose- or lactulose-based hydrogen breath testing may be used to evaluate for small intestinal bacterial overgrowth,” the guidance says. Blood testing may be used to rule out celiac disease, and, if positive, a definitive diagnosis should be confirmed with small bowel tissue biopsy obtained during an upper endoscopy, Dr. Moshiree and her colleagues wrote.
Endoscopy and imaging should be restricted to patients with alarm features such as vomiting or weight loss, rapid worsening of symptoms, or an abnormal physical exam. Tests such as gastric emptying transit studies should not be routinely ordered unless nausea and vomiting are present. Similarly, whole-gut motility studies should be ordered only if there are symptoms suggestive of motility disorders, with testing carried out at specialized centers.
When constipation occurs with bloating, clinicians should use anorectal physiology testing to rule out a pelvic-floor disorder, which, if present, can be treated with pelvic floor biofeedback training. Constipation in the context of bloating may also be treated with laxatives. Probiotics are not advised as treatment for bloating and distention in this guidance, given a lack of robust studies. However, neuromodulators may help reduce visceral or gut hypersensitivity and improve psychological comorbidities if these are present, the authors wrote.
Conditions treated with dietary modifications should be overseen by dietitians, and diaphragmatic breathing and neuromodulators can be used to treat a condition called abdominophrenic dyssynergia, the guidance says.
“We tried to make it clinically useful,” Dr. Moshiree said of the practice update, which was not the result of systematic reviews or meta-analyses of multicenter randomized controlled trials. The update contains no ratings on its recommendations and does not grade the evidence used. Rather, the three coauthors looked to results from published randomized trials and observational studies, along with their own expert opinion.
For example, the guidance’s best practice advice on abdominophrenic dyssynergia came from single center studies in Italy where bloating improved with use of biofeedback therapy for this condition. Although this was a single center study, experts have found that biofeedback therapy is helpful for relaxing the pelvic floor muscles which can help bloating and distension symptoms.
Dr. Moshiree also pointed to a 2021 narrative review by Brian E. Lacy, MD. and David Cangemi, MD, of the Mayo Clinic in Jacksonville, Fla., that helped inform the framework for this clinical practice update.
Dr. Moshiree disclosed financial relationships with several pharmaceutical companies including Salix, AbbVie, Medtronic, and Takeda. Her two coauthors, Douglas Drossman, MD, of the Rome Foundation and the University of North Carolina, Chapel Hill, and Aasma Shaukat, MD, of New York University, also disclosed industry support.
A new Clinical Practice Update from the AGA on belching, abdominal bloating, and distention offers practical management strategies for a class of disorders that, while highly prevalent, can be confusing to clinicians because of their nonspecific and overlapping symptomatology and wide range of possible causes.
The expert review, published online in Gastroenterology, is dedicated to these specific disorders, which, when not caused by bacteria, food intolerance, or autoimmune disease, are increasingly viewed as stemming from dysregulation of the brain-gut axis, and therefore responsive to interventions such as biofeedback therapy and central nervous system modulators, including antidepressants referred to as neuromodulators due to their pain modulating effects in the gut.
Baharak Moshiree, MD, of Atrium Health, Wake Forest Medical University, Charlotte, N.C., the lead author, said the guidance is aimed at GI specialists as much as primary care physicians and other providers who treat patients with these disorders.
Clinicians may not always know which diagnostic studies to order for a patient with bloating, distention, or belching, Dr. Moshiree said, and since large randomized controlled trials in these patient groups are not available, making evidence-based treatment recommendations is challenging. Because the disorders are ubiquitous, “there’s a lot of social media attention around them, and these include fad diets and drugs labeled as medical foods, like probiotics, that patients will often try.”
The guidance includes 15 best practice advice statements along with two diagnostic and treatment algorithms, one for belching and the other for bloating and distention.
For belching, the authors stress discerning between gastric and supragastric belching using clinical history and examination, and if needed, impedance Ph monitoring. For supragastric belching, or esophageal belching, treatment considerations may include cognitive behavioral therapy, biofeedback training, and neuromodulator (antidepressant) drugs either alone or combined with psychological therapies.
Abdominal bloating and distention should be diagnosed using the Rome IV criteria, and in patients with suspected carbohydrate enzyme deficiencies, dietary restriction of potentially problematic carbohydrates or breath testing may be used to rule out intolerance. In a subset of at-risk patients, “small bowel aspiration and glucose- or lactulose-based hydrogen breath testing may be used to evaluate for small intestinal bacterial overgrowth,” the guidance says. Blood testing may be used to rule out celiac disease, and, if positive, a definitive diagnosis should be confirmed with small bowel tissue biopsy obtained during an upper endoscopy, Dr. Moshiree and her colleagues wrote.
Endoscopy and imaging should be restricted to patients with alarm features such as vomiting or weight loss, rapid worsening of symptoms, or an abnormal physical exam. Tests such as gastric emptying transit studies should not be routinely ordered unless nausea and vomiting are present. Similarly, whole-gut motility studies should be ordered only if there are symptoms suggestive of motility disorders, with testing carried out at specialized centers.
When constipation occurs with bloating, clinicians should use anorectal physiology testing to rule out a pelvic-floor disorder, which, if present, can be treated with pelvic floor biofeedback training. Constipation in the context of bloating may also be treated with laxatives. Probiotics are not advised as treatment for bloating and distention in this guidance, given a lack of robust studies. However, neuromodulators may help reduce visceral or gut hypersensitivity and improve psychological comorbidities if these are present, the authors wrote.
Conditions treated with dietary modifications should be overseen by dietitians, and diaphragmatic breathing and neuromodulators can be used to treat a condition called abdominophrenic dyssynergia, the guidance says.
“We tried to make it clinically useful,” Dr. Moshiree said of the practice update, which was not the result of systematic reviews or meta-analyses of multicenter randomized controlled trials. The update contains no ratings on its recommendations and does not grade the evidence used. Rather, the three coauthors looked to results from published randomized trials and observational studies, along with their own expert opinion.
For example, the guidance’s best practice advice on abdominophrenic dyssynergia came from single center studies in Italy where bloating improved with use of biofeedback therapy for this condition. Although this was a single center study, experts have found that biofeedback therapy is helpful for relaxing the pelvic floor muscles which can help bloating and distension symptoms.
Dr. Moshiree also pointed to a 2021 narrative review by Brian E. Lacy, MD. and David Cangemi, MD, of the Mayo Clinic in Jacksonville, Fla., that helped inform the framework for this clinical practice update.
Dr. Moshiree disclosed financial relationships with several pharmaceutical companies including Salix, AbbVie, Medtronic, and Takeda. Her two coauthors, Douglas Drossman, MD, of the Rome Foundation and the University of North Carolina, Chapel Hill, and Aasma Shaukat, MD, of New York University, also disclosed industry support.
FROM GASTROENTEROLOGY
Hemostatic powder superior in controlling tumor bleeding
The findings, published online in Gastroenterology (2023 Jun 3. doi: 10.1053/j.gastro.2023.05.042), come from the largest randomized trial to date of TC-325 (Hemospray, Cook Medical), compared with standard endoscopic hemostatic interventions for tumor bleeding.
For their research, Rapat Pittayanon, MD, of Chulalongkorn University in Bangkok and her colleagues, randomized patients (60% male, mean age 63) with active malignant upper or lower GI bleeding and low disability levels related to their cancers (ECOG score 0-2). The study was conducted at nine hospitals in Thailand.
The 106 patients who passed screening underwent either TC-325 or standard endoscopic hemostasis, which could involve use of thermal or mechanical methods or adrenaline injection, alone or combined with another modality, at the endoscopist’s discretion. Crossover between treatment allocations was permitted if hemostasis was not achieved. Investigators assessed rates of immediate hemostasis and rebleeding at 30 days.
Dr. Pittayanon and colleagues found rebleeding to be significantly lower among TC-325 treated patients, at 2.1%, compared with 21.3% for standard care (odds ratio, 0.09; 95% confidence interval, 0.01-0.80; P = .03). Rates of immediate hemostasis were 100% for TC-325–treated subjects, compared with 68.6% in the conventional-treatment group (OR, 1.45; 95% CI, 0.93-2.29; P < .001).
None of the 55 patients in the TC-325 group underwent crossover treatment, but 15 patients in the standard care group were crossed over to TC-325 after their endoscopic treatment was deemed to have failed. One-fifth of patients who got TC-325 as a crossover treatment developed rebleeding at 30 days, which the investigators surmised was related to mucosal damage incurred during the endoscopic procedure.
The study was not powered to adequately assess survival outcomes. Seven patients in the TC-325 group and four in the conventional care group died before 30 days’ follow-up, and no death was directly related to recurrent tumor bleeding.
“To our knowledge, our trial is the first to show such significant findings in an RCT setting, which now provide a long-awaited efficacious hemostatic approach where one had been lacking when managing patients with malignant GI bleeding,” the investigators wrote in their analysis.
“Perhaps most importantly, this carefully controlled study also highlights the unreliable hemostatic effect of standard endoscopic modalities available for GI tumor hemostasis, with high 30-day rebleeding rates in our patient population.”
Dr. Pittayanon and colleagues noted several limitations of their study. These included the inability to blind patients to an endoscopist, which “may have influenced subsequent management decisions … including the decision to cross over.”
Only in 5 of 15 cases of crossover did the treating endoscopist provide photo evidence of treatment failure as required by the trial’s protocol. Also, the use of adrenaline injection alone was permitted in the study, in contrast to best practice guidelines for endoscopic hemostasis to treat peptic ulcer bleeding. Finally, the study was conducted in Thailand, potentially reducing the generalizability of the results.
The study was funded by King Chulalongkorn Memorial Hospital; the Thai Red Cross; and Chulalongkorn University. Cook Medical donated some of the TC-325 kits used in the study.
One study coauthor, Alan N. Barkun, disclosed consulting work for Medtronic and past paid work for Cook Medical. The remaining authors disclosed no conflicts of interest.
Gastrointestinal tumor bleeding is a challenging problem that can lead to prolonged hospitalization and interruption of curative or palliative oncologic interventions. Standard endoscopic hemostasis interventions, such as subepithelial epinephrine injection and mechanical and thermal treatments, can be limited because of the underlying tumor biology that alters angiogenesis, distorts the surrounding mucosa, and undermines the normal coagulation process. This randomized trial by Pittayanon et al. demonstrated that the hemostatic powder TC-325 (Hemospray, Cook Medical) was superior to standard endoscopic intervention in achieving immediate hemostasis (100% vs. 69%) and reducing 30-day rebleeding rate (2% vs. 21%).
As clinicians and endoscopists, our ultimate goals in treating GI tumor bleeding are to provide safe and efficient hemostasis, to decrease hospital stay and to minimize delay and interruption of oncologic or palliative treatments. This study advocates that TC-325 may be a better primary option than standard endoscopic treatments for GI tumor bleeding in the appropriate setting. Safety, efficacy, and feasibility studies comparing TC-325 to the other hemostatic powder products are needed.
Malorie K. Simons, MD, is an interventional endoscopist with Fox Chase Cancer Center, Temple University Health System, Philadelphia. She specializes in colorectal cancer, esophageal cancer, and gastric cancer. She has no conflicts of interest.
Gastrointestinal tumor bleeding is a challenging problem that can lead to prolonged hospitalization and interruption of curative or palliative oncologic interventions. Standard endoscopic hemostasis interventions, such as subepithelial epinephrine injection and mechanical and thermal treatments, can be limited because of the underlying tumor biology that alters angiogenesis, distorts the surrounding mucosa, and undermines the normal coagulation process. This randomized trial by Pittayanon et al. demonstrated that the hemostatic powder TC-325 (Hemospray, Cook Medical) was superior to standard endoscopic intervention in achieving immediate hemostasis (100% vs. 69%) and reducing 30-day rebleeding rate (2% vs. 21%).
As clinicians and endoscopists, our ultimate goals in treating GI tumor bleeding are to provide safe and efficient hemostasis, to decrease hospital stay and to minimize delay and interruption of oncologic or palliative treatments. This study advocates that TC-325 may be a better primary option than standard endoscopic treatments for GI tumor bleeding in the appropriate setting. Safety, efficacy, and feasibility studies comparing TC-325 to the other hemostatic powder products are needed.
Malorie K. Simons, MD, is an interventional endoscopist with Fox Chase Cancer Center, Temple University Health System, Philadelphia. She specializes in colorectal cancer, esophageal cancer, and gastric cancer. She has no conflicts of interest.
Gastrointestinal tumor bleeding is a challenging problem that can lead to prolonged hospitalization and interruption of curative or palliative oncologic interventions. Standard endoscopic hemostasis interventions, such as subepithelial epinephrine injection and mechanical and thermal treatments, can be limited because of the underlying tumor biology that alters angiogenesis, distorts the surrounding mucosa, and undermines the normal coagulation process. This randomized trial by Pittayanon et al. demonstrated that the hemostatic powder TC-325 (Hemospray, Cook Medical) was superior to standard endoscopic intervention in achieving immediate hemostasis (100% vs. 69%) and reducing 30-day rebleeding rate (2% vs. 21%).
As clinicians and endoscopists, our ultimate goals in treating GI tumor bleeding are to provide safe and efficient hemostasis, to decrease hospital stay and to minimize delay and interruption of oncologic or palliative treatments. This study advocates that TC-325 may be a better primary option than standard endoscopic treatments for GI tumor bleeding in the appropriate setting. Safety, efficacy, and feasibility studies comparing TC-325 to the other hemostatic powder products are needed.
Malorie K. Simons, MD, is an interventional endoscopist with Fox Chase Cancer Center, Temple University Health System, Philadelphia. She specializes in colorectal cancer, esophageal cancer, and gastric cancer. She has no conflicts of interest.
The findings, published online in Gastroenterology (2023 Jun 3. doi: 10.1053/j.gastro.2023.05.042), come from the largest randomized trial to date of TC-325 (Hemospray, Cook Medical), compared with standard endoscopic hemostatic interventions for tumor bleeding.
For their research, Rapat Pittayanon, MD, of Chulalongkorn University in Bangkok and her colleagues, randomized patients (60% male, mean age 63) with active malignant upper or lower GI bleeding and low disability levels related to their cancers (ECOG score 0-2). The study was conducted at nine hospitals in Thailand.
The 106 patients who passed screening underwent either TC-325 or standard endoscopic hemostasis, which could involve use of thermal or mechanical methods or adrenaline injection, alone or combined with another modality, at the endoscopist’s discretion. Crossover between treatment allocations was permitted if hemostasis was not achieved. Investigators assessed rates of immediate hemostasis and rebleeding at 30 days.
Dr. Pittayanon and colleagues found rebleeding to be significantly lower among TC-325 treated patients, at 2.1%, compared with 21.3% for standard care (odds ratio, 0.09; 95% confidence interval, 0.01-0.80; P = .03). Rates of immediate hemostasis were 100% for TC-325–treated subjects, compared with 68.6% in the conventional-treatment group (OR, 1.45; 95% CI, 0.93-2.29; P < .001).
None of the 55 patients in the TC-325 group underwent crossover treatment, but 15 patients in the standard care group were crossed over to TC-325 after their endoscopic treatment was deemed to have failed. One-fifth of patients who got TC-325 as a crossover treatment developed rebleeding at 30 days, which the investigators surmised was related to mucosal damage incurred during the endoscopic procedure.
The study was not powered to adequately assess survival outcomes. Seven patients in the TC-325 group and four in the conventional care group died before 30 days’ follow-up, and no death was directly related to recurrent tumor bleeding.
“To our knowledge, our trial is the first to show such significant findings in an RCT setting, which now provide a long-awaited efficacious hemostatic approach where one had been lacking when managing patients with malignant GI bleeding,” the investigators wrote in their analysis.
“Perhaps most importantly, this carefully controlled study also highlights the unreliable hemostatic effect of standard endoscopic modalities available for GI tumor hemostasis, with high 30-day rebleeding rates in our patient population.”
Dr. Pittayanon and colleagues noted several limitations of their study. These included the inability to blind patients to an endoscopist, which “may have influenced subsequent management decisions … including the decision to cross over.”
Only in 5 of 15 cases of crossover did the treating endoscopist provide photo evidence of treatment failure as required by the trial’s protocol. Also, the use of adrenaline injection alone was permitted in the study, in contrast to best practice guidelines for endoscopic hemostasis to treat peptic ulcer bleeding. Finally, the study was conducted in Thailand, potentially reducing the generalizability of the results.
The study was funded by King Chulalongkorn Memorial Hospital; the Thai Red Cross; and Chulalongkorn University. Cook Medical donated some of the TC-325 kits used in the study.
One study coauthor, Alan N. Barkun, disclosed consulting work for Medtronic and past paid work for Cook Medical. The remaining authors disclosed no conflicts of interest.
The findings, published online in Gastroenterology (2023 Jun 3. doi: 10.1053/j.gastro.2023.05.042), come from the largest randomized trial to date of TC-325 (Hemospray, Cook Medical), compared with standard endoscopic hemostatic interventions for tumor bleeding.
For their research, Rapat Pittayanon, MD, of Chulalongkorn University in Bangkok and her colleagues, randomized patients (60% male, mean age 63) with active malignant upper or lower GI bleeding and low disability levels related to their cancers (ECOG score 0-2). The study was conducted at nine hospitals in Thailand.
The 106 patients who passed screening underwent either TC-325 or standard endoscopic hemostasis, which could involve use of thermal or mechanical methods or adrenaline injection, alone or combined with another modality, at the endoscopist’s discretion. Crossover between treatment allocations was permitted if hemostasis was not achieved. Investigators assessed rates of immediate hemostasis and rebleeding at 30 days.
Dr. Pittayanon and colleagues found rebleeding to be significantly lower among TC-325 treated patients, at 2.1%, compared with 21.3% for standard care (odds ratio, 0.09; 95% confidence interval, 0.01-0.80; P = .03). Rates of immediate hemostasis were 100% for TC-325–treated subjects, compared with 68.6% in the conventional-treatment group (OR, 1.45; 95% CI, 0.93-2.29; P < .001).
None of the 55 patients in the TC-325 group underwent crossover treatment, but 15 patients in the standard care group were crossed over to TC-325 after their endoscopic treatment was deemed to have failed. One-fifth of patients who got TC-325 as a crossover treatment developed rebleeding at 30 days, which the investigators surmised was related to mucosal damage incurred during the endoscopic procedure.
The study was not powered to adequately assess survival outcomes. Seven patients in the TC-325 group and four in the conventional care group died before 30 days’ follow-up, and no death was directly related to recurrent tumor bleeding.
“To our knowledge, our trial is the first to show such significant findings in an RCT setting, which now provide a long-awaited efficacious hemostatic approach where one had been lacking when managing patients with malignant GI bleeding,” the investigators wrote in their analysis.
“Perhaps most importantly, this carefully controlled study also highlights the unreliable hemostatic effect of standard endoscopic modalities available for GI tumor hemostasis, with high 30-day rebleeding rates in our patient population.”
Dr. Pittayanon and colleagues noted several limitations of their study. These included the inability to blind patients to an endoscopist, which “may have influenced subsequent management decisions … including the decision to cross over.”
Only in 5 of 15 cases of crossover did the treating endoscopist provide photo evidence of treatment failure as required by the trial’s protocol. Also, the use of adrenaline injection alone was permitted in the study, in contrast to best practice guidelines for endoscopic hemostasis to treat peptic ulcer bleeding. Finally, the study was conducted in Thailand, potentially reducing the generalizability of the results.
The study was funded by King Chulalongkorn Memorial Hospital; the Thai Red Cross; and Chulalongkorn University. Cook Medical donated some of the TC-325 kits used in the study.
One study coauthor, Alan N. Barkun, disclosed consulting work for Medtronic and past paid work for Cook Medical. The remaining authors disclosed no conflicts of interest.
FROM GASTROENTEROLOGY