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For much of the past 50 years, many of the drugs used in dermatology have been adopted – and often adapted – from other specialties and used for dermatologic conditions.
“Almost every drug was more or less a hand-me-down” developed first for cancer or other diseases and found later, often serendipitously, to be useful for the skin, said William Eaglstein, MD, thinking back to the 1970s and recalling steroids, tetracyclines, methotrexate, and 5-flourouracil. “The perception always was that skin diseases weren’t serious, that the market was small.”
Much has changed. by dermatologist investigators, and “more and more companies are recognizing the importance of our diseases and the ability to get a return on investment,” said Dr. Eaglstein, past professor and chair of the departments of dermatology at the University of Miami and the University of Pittsburgh, who worked in industry after his academic career.
Psoriasis was a game changer, he and other dermatologists said in interviews. The tumor necrosis factor (TNF)–alpha blockers were first used for other indications, but their marked follow-on success in psoriasis “offered proof of concept clinically – showing that by targeting immune pathways in the skin we could achieve a clinical effect – and proof of concept commercially” that dermatology drugs are worth pursuing by pharmaceutical companies, said William Ju, MD, a cofounder and president of Advancing Innovation in Dermatology, a nonprofit organization that brings together stakeholders to develop novel dermatologic drugs and products.
This resulted in the approval of subsequent biologics, such as ustekinumab (Stelara) which inhibits the signaling of interleukin (IL)–12/IL-23, for psoriasis as their initial indication. Then, biologics targeting IL-17 followed this dermatology-first approach. “Researchers have continued further dissecting out the immunopathological pathways, and antibody drugs targeting IL-23p19 have been approved for psoriasis as the lead indication,” said Dr. Ju, a dermatologist who has worked in industry.
Seth Orlow, MD, PhD, who chairs the department of dermatology at NYU Langone Health, remembers the 1970s through the 1990s as the “era of topicals” developed for dermatologic conditions – topical antifungals, topical corticosteroids, and topical retinoids. The next decade was characterized by formulation tweaks and few novel treatments for dermatology, said Dr. Orlow, who is also professor of pediatric dermatology and director of the program in cutaneous biology at New York University.
Now, given the succession of psoriasis discoveries in the last decade, “large companies are interested in dermatology,” he said in an interview. “There’s an explosion of interest in atopic dermatitis. … and companies are dipping their toes in the water for alopecia areata and vitiligo. That’s amazing.”
Rare diseases like epidermolysis bullosa, ichthyosis, and basal cell nevus syndrome are getting attention as well, boosted by the Orphan Drug Act of 1983, in addition to increased research on disease pathways and growing appreciation of skin diseases. “There’s a lot under development, from small molecules to biologics to gene-based therapies,” Dr. Orlow commented.
The new frontier of atopic dermatitis
The approval in 2017 of dupilumab (Dupixent), a monoclonal antibody that inhibits the signaling of both IL-4 and IL-13) for moderate-severe atopic dermatitis (AD) in adults illustrates the new standing of dermatologic diseases in the field of drug development and commercialization. “Atopic dermatitis had always been the forgotten chronic disease in dermatology. … We’ve had no good treatments,” said Eric Simpson, MD, professor of dermatology at Oregon Health & Science University, Portland. “Dupilumab coming to the forefront [as a dermatology-first indication] has changed the entire perspective of the field. … Everyone is now trying to find the next best drug.”
As with psoriasis, a targeted therapy for AD was made possible by the development in the 1990s of monoclonal antibody technology and the ensuing ability to create biologics that target specific molecules in the body – as well as bedside-to-bench research that homed in on the involvement of particular cytokines.
But there also is a “new understanding of the burden of the disease,” Dr. Simpson observed. In the last 5 years, he said, research funded by the National Eczema Association documented that AD “not only causes inflammation of the skin … but that it affects people at school and in the workplace, that people have multiple mental health comorbidities and skin infections, and that the disease profoundly affects the entire patient in ways that weren’t really recognized or appreciated.”
Having evolved in the footsteps of psoriasis, AD is at a higher starting point in terms of the safety and efficacy of its first biologic, sources said. On the other hand, AD is a much more complex and heterogeneous disease, and researchers are trying to determine which immune pathways and cytokines are most important – and in which populations.
“We’re at the beginning. We’re trying to figure out how to get 80% of patients clear or almost clear [as we can now with psoriasis biologics] rather than almost 40% [as in the dupilumab pivotal trials],” said Dr. Simpson, former cochair of the National Eczema Association’s scientific committee. Public data from ongoing phase 2 and 3 trials of other Th2 cytokine inhibitors suggest that 25%-45% of enrolled patients achieve high levels of clearance, he noted.
Emma Guttman-Yassky, MD, PhD, Sol and Clara Kest Professor and vice-chair for research in the department of dermatology at the Icahn School of Medicine at Mount Sinai, New York, said that AD’s heterogeneity involves “many factors, like ethnicity, age … and whether they have an atopic background such as asthma.”
Her research is showing, for instance, that AD in Asian and black patients is different than AD in European-American patients, and that the presence of comorbidities may well have treatment implications. She has also shown that children may have a different phenotype than adults, with greater activation of the Th17 axis that typifies psoriasis.
“For certain patients, we may need to target more than one pathway, or target a different pathway than the Th2 pathway. And treatment may be different in the setting of comorbidities,” said Dr. Guttman-Yassky, who is also director of the laboratory of inflammatory skin diseases at Mount Sinai. “We may think of one treatment – dupilumab, for example – for someone who has asthma and AD. But for patients who don’t have asthma and are Asian, for instance, or for children, we may need additional agents.”
Her research over the years on AD has taught her the importance of human studies over mouse model studies; it was in humans, she noted, that she and other investigators demonstrated “without doubt” that AD is an immune disease and not simply a barrier disease. The Th2 cytokine pathway appears to play the predominant role in AD, though “there still is a strong Th1 component,” she said.
“We’re in a better position to figure this out today [than in the past 20 or even 10 years],” said Dr. Guttman-Yassky, who recalls being told years ago that AD was a “dead end,” that it “would kill [her] career.” Given the evolution of science and the recognition of comorbidities and seriousness of dermatologic diseases, “the stars are aligned to get more [therapies] to these patients.”
Janus kinase (JAK) inhibitors are among these therapies. Three JAK inhibitors are in or have recently completed phase 3 studies for AD; two are currently approved for rheumatoid arthritis, and the other has been designed specifically for AD, Dr. Simpson pointed out. The drugs are oral small molecule drugs that block the JAK signaling pathways for certain proinflammatory cytokines.
“The JAK inhibitors are a real exciting story for dermatology,” he said. “Theoretically, by blocking more cytokines than biologics do, there could be some safety issues – that’s why we’re awaiting big phase 3 study results so we can figure out the risk-benefit balance and guide our patients as to which drug is best.”
Andrew Blauvelt, MD, MBA, president of Oregon Medical Research Center in Portland – a stand-alone dermatology clinical trial center founded in 1998 – likes to envision the evolution of drugs for dermatologic conditions as a funnel, with the most broad-acting drugs at the wide top of the funnel and the most targeted drugs at the bottom tip.
JAK inhibitors, he said, sit near the middle – more targeted and safer than cyclosporine and methotrexate, for instance, but not as targeted as the biologics now available for psoriasis and being developed for AD. “The oral medications that have been developed for psoriasis and those coming for AD are not quite as targeted to the disease,” he noted. “JAK inhibitors have great efficacy – it’s more a question of safety and being able to treat without causing collateral damage.”
Dr. Blauvelt expects the armamentarium of new drugs approved for AD to go from one (dupilumab) to seven within the next 2 years. This will include three new biologics and three new oral JAK inhibitors, he predicts. As the specialty sorts through and integrates these new drugs into practice, dermatologists will increasingly personalize treatment and will face the “nonscientific” challenge of the cost of new therapies and patient access to them, he noted.
In the meantime, said Dr. Simpson, recent drug discoveries have driven more non–pharmaceutical-funded translational research aimed at understanding the underlying biology of AD. The National Institutes of Health, for instance, “is interested in dupilumab and its impact on the skin barrier and skin defense mechanisms,” he said. “We’ll learn a lot more [in coming years].”
Spillover to other diseases
JAK inhibitors – some in oral and some in topical form – are showing efficacy in ongoing research for alopecia areata (AA) and vitiligo as well, Dr. Blauvelt said.
“We’re understanding more about the pathophysiology of these diseases, which historically have been tough diseases for dermatologists to treat,” he said. “The successes in alopecia areata and vitiligo are incredibly exciting actually – it’s very exciting to see hair and pigment coming back. And as we learn more, we should be able to develop [additional] drugs that are more disease targeted than the JAK inhibitors.”
Already, some of the biologics used to treat psoriasis have been studied in patients with hidradenitis suppurativa (HS), a disease in which painful lumps and sometimes tunnels form under the skin, with some success; adalimumab (Humira), a TNF-inhibitor, is now FDA approved for the treatment of moderate-severe HS, and studies are ongoing of IL-17 and IL-23 blockers for the disease.
“The pathophysiology [of HS] is very complex; it’s not nearly as straightforward as psoriasis, and there haven’t been any major breakthroughs yet,” Dr. Blauvelt said. “But the drugs seem to be working better than historical alternatives.”
Regarding AA, Dr. Guttman-Yassky, who is participating in a study of dupilumab for AA, recently found in a retrospective cross-sectional study that patients with the condition are more likely to have atopic comorbidities – asthma, allergic rhinitis, and AD, for instance. “The more comorbid conditions, the greater the risk of developing alopecia areata,” she said. “That could point to a potential pathogenic role of the Th2 axis in the disorder [challenging the traditional view of AA as a singularly Th1-centered disease.] The future will tell.”
Action on rare skin diseases
Both large and small companies have moved into the orphan drug space, investing in research and pursuing orphan drug indications for dermatologic conditions, because “it’s clear now in the marketplace that companies can develop effective drugs for rare disorders and be quite successful,” Dr. Orlow said.
According to a recent analysis, as a result of incentives for rare disease drug development contained in the Orphan Drug Act, 72 indications have been approved for rare skin disease, skin-related cancers, and hereditary disorders with prominent dermatologic manifestations since the law was passed in 1983 (J. Am. Acad. Dermatol. 2019;81[3]:867-77).
Epidermolysis bullosa (EB) is a good example, he and other sources said, of commercial interests merging with growing knowledge of disease pathogenesis as well as the tools needed to develop new treatments.
Research by dermatology scientists and others over the past 40 years, Dr. Ju explained, shed light on the molecular basis underlying the structure and function of the junction between the epidermis and dermis, including the pivotal role that type VII collagen plays in the normal adhesion of these two layers. Researchers then learned that, in EB, the family of genetic diseases characterized by skin fragility, “dystrophic types are caused by mutations in the gene encoding type VII collagen,” he said.
“Just as the advent of monoclonal antibodies allowed us to start attacking psoriasis and atopic dermatitis in unprecedented ways, the advent of gene therapy allows us to potentially address the fundamental molecular genetic defect of various types of EB,” Dr. Ju said.
While gene therapy is “still in its infancy,” companies have begun using the tools to address EB. One gene therapy in the pipeline – in phase 3 clinical trial testing – involves grafting back into patients with recessive dystrophic EB their skin cells that have been genetically modified to produce a correct (nonmutated) type VII collagen, he said.
Basal cell nevus syndrome, or Gorlin syndrome, a rare disease in which patients develop a multitude of basal cell carcinoma tumors, is another example of a “dermatology first” approach, Dr. Ju said. Research identified a genetic mutation that causes the hedgehog signaling pathway to be inappropriately activated in the disease, and a drug, vismodegib, was developed to inhibit this pathway. The drug was initially approved for patients with metastatic basal cell cancer and types of advanced basal cell cancer, and is now being tested in cancers affecting other organs, he said.
Basal cell cancer “is a huge market, but it was really unrecognized in the past,” Dr. Eaglstein said. “Seeing drugs come to market for basal cell cancer – this wouldn’t have happened [decades ago].”
Dr. Ju has worked in the pharmaceutical industry; all other sources in this story have worked with pharmaceutical manufacturers of treatments that are being developed or have been approved to treat dermatologic diseases mentioned in this story. In addition to Dr. Ju, Dr. Eaglstein and Dr. Orlow are cofounders of the Advancing Innovation in Dermatology group; Dr. Orlow is a member of the program committee for the organization’s dermatology summit conference.
For much of the past 50 years, many of the drugs used in dermatology have been adopted – and often adapted – from other specialties and used for dermatologic conditions.
“Almost every drug was more or less a hand-me-down” developed first for cancer or other diseases and found later, often serendipitously, to be useful for the skin, said William Eaglstein, MD, thinking back to the 1970s and recalling steroids, tetracyclines, methotrexate, and 5-flourouracil. “The perception always was that skin diseases weren’t serious, that the market was small.”
Much has changed. by dermatologist investigators, and “more and more companies are recognizing the importance of our diseases and the ability to get a return on investment,” said Dr. Eaglstein, past professor and chair of the departments of dermatology at the University of Miami and the University of Pittsburgh, who worked in industry after his academic career.
Psoriasis was a game changer, he and other dermatologists said in interviews. The tumor necrosis factor (TNF)–alpha blockers were first used for other indications, but their marked follow-on success in psoriasis “offered proof of concept clinically – showing that by targeting immune pathways in the skin we could achieve a clinical effect – and proof of concept commercially” that dermatology drugs are worth pursuing by pharmaceutical companies, said William Ju, MD, a cofounder and president of Advancing Innovation in Dermatology, a nonprofit organization that brings together stakeholders to develop novel dermatologic drugs and products.
This resulted in the approval of subsequent biologics, such as ustekinumab (Stelara) which inhibits the signaling of interleukin (IL)–12/IL-23, for psoriasis as their initial indication. Then, biologics targeting IL-17 followed this dermatology-first approach. “Researchers have continued further dissecting out the immunopathological pathways, and antibody drugs targeting IL-23p19 have been approved for psoriasis as the lead indication,” said Dr. Ju, a dermatologist who has worked in industry.
Seth Orlow, MD, PhD, who chairs the department of dermatology at NYU Langone Health, remembers the 1970s through the 1990s as the “era of topicals” developed for dermatologic conditions – topical antifungals, topical corticosteroids, and topical retinoids. The next decade was characterized by formulation tweaks and few novel treatments for dermatology, said Dr. Orlow, who is also professor of pediatric dermatology and director of the program in cutaneous biology at New York University.
Now, given the succession of psoriasis discoveries in the last decade, “large companies are interested in dermatology,” he said in an interview. “There’s an explosion of interest in atopic dermatitis. … and companies are dipping their toes in the water for alopecia areata and vitiligo. That’s amazing.”
Rare diseases like epidermolysis bullosa, ichthyosis, and basal cell nevus syndrome are getting attention as well, boosted by the Orphan Drug Act of 1983, in addition to increased research on disease pathways and growing appreciation of skin diseases. “There’s a lot under development, from small molecules to biologics to gene-based therapies,” Dr. Orlow commented.
The new frontier of atopic dermatitis
The approval in 2017 of dupilumab (Dupixent), a monoclonal antibody that inhibits the signaling of both IL-4 and IL-13) for moderate-severe atopic dermatitis (AD) in adults illustrates the new standing of dermatologic diseases in the field of drug development and commercialization. “Atopic dermatitis had always been the forgotten chronic disease in dermatology. … We’ve had no good treatments,” said Eric Simpson, MD, professor of dermatology at Oregon Health & Science University, Portland. “Dupilumab coming to the forefront [as a dermatology-first indication] has changed the entire perspective of the field. … Everyone is now trying to find the next best drug.”
As with psoriasis, a targeted therapy for AD was made possible by the development in the 1990s of monoclonal antibody technology and the ensuing ability to create biologics that target specific molecules in the body – as well as bedside-to-bench research that homed in on the involvement of particular cytokines.
But there also is a “new understanding of the burden of the disease,” Dr. Simpson observed. In the last 5 years, he said, research funded by the National Eczema Association documented that AD “not only causes inflammation of the skin … but that it affects people at school and in the workplace, that people have multiple mental health comorbidities and skin infections, and that the disease profoundly affects the entire patient in ways that weren’t really recognized or appreciated.”
Having evolved in the footsteps of psoriasis, AD is at a higher starting point in terms of the safety and efficacy of its first biologic, sources said. On the other hand, AD is a much more complex and heterogeneous disease, and researchers are trying to determine which immune pathways and cytokines are most important – and in which populations.
“We’re at the beginning. We’re trying to figure out how to get 80% of patients clear or almost clear [as we can now with psoriasis biologics] rather than almost 40% [as in the dupilumab pivotal trials],” said Dr. Simpson, former cochair of the National Eczema Association’s scientific committee. Public data from ongoing phase 2 and 3 trials of other Th2 cytokine inhibitors suggest that 25%-45% of enrolled patients achieve high levels of clearance, he noted.
Emma Guttman-Yassky, MD, PhD, Sol and Clara Kest Professor and vice-chair for research in the department of dermatology at the Icahn School of Medicine at Mount Sinai, New York, said that AD’s heterogeneity involves “many factors, like ethnicity, age … and whether they have an atopic background such as asthma.”
Her research is showing, for instance, that AD in Asian and black patients is different than AD in European-American patients, and that the presence of comorbidities may well have treatment implications. She has also shown that children may have a different phenotype than adults, with greater activation of the Th17 axis that typifies psoriasis.
“For certain patients, we may need to target more than one pathway, or target a different pathway than the Th2 pathway. And treatment may be different in the setting of comorbidities,” said Dr. Guttman-Yassky, who is also director of the laboratory of inflammatory skin diseases at Mount Sinai. “We may think of one treatment – dupilumab, for example – for someone who has asthma and AD. But for patients who don’t have asthma and are Asian, for instance, or for children, we may need additional agents.”
Her research over the years on AD has taught her the importance of human studies over mouse model studies; it was in humans, she noted, that she and other investigators demonstrated “without doubt” that AD is an immune disease and not simply a barrier disease. The Th2 cytokine pathway appears to play the predominant role in AD, though “there still is a strong Th1 component,” she said.
“We’re in a better position to figure this out today [than in the past 20 or even 10 years],” said Dr. Guttman-Yassky, who recalls being told years ago that AD was a “dead end,” that it “would kill [her] career.” Given the evolution of science and the recognition of comorbidities and seriousness of dermatologic diseases, “the stars are aligned to get more [therapies] to these patients.”
Janus kinase (JAK) inhibitors are among these therapies. Three JAK inhibitors are in or have recently completed phase 3 studies for AD; two are currently approved for rheumatoid arthritis, and the other has been designed specifically for AD, Dr. Simpson pointed out. The drugs are oral small molecule drugs that block the JAK signaling pathways for certain proinflammatory cytokines.
“The JAK inhibitors are a real exciting story for dermatology,” he said. “Theoretically, by blocking more cytokines than biologics do, there could be some safety issues – that’s why we’re awaiting big phase 3 study results so we can figure out the risk-benefit balance and guide our patients as to which drug is best.”
Andrew Blauvelt, MD, MBA, president of Oregon Medical Research Center in Portland – a stand-alone dermatology clinical trial center founded in 1998 – likes to envision the evolution of drugs for dermatologic conditions as a funnel, with the most broad-acting drugs at the wide top of the funnel and the most targeted drugs at the bottom tip.
JAK inhibitors, he said, sit near the middle – more targeted and safer than cyclosporine and methotrexate, for instance, but not as targeted as the biologics now available for psoriasis and being developed for AD. “The oral medications that have been developed for psoriasis and those coming for AD are not quite as targeted to the disease,” he noted. “JAK inhibitors have great efficacy – it’s more a question of safety and being able to treat without causing collateral damage.”
Dr. Blauvelt expects the armamentarium of new drugs approved for AD to go from one (dupilumab) to seven within the next 2 years. This will include three new biologics and three new oral JAK inhibitors, he predicts. As the specialty sorts through and integrates these new drugs into practice, dermatologists will increasingly personalize treatment and will face the “nonscientific” challenge of the cost of new therapies and patient access to them, he noted.
In the meantime, said Dr. Simpson, recent drug discoveries have driven more non–pharmaceutical-funded translational research aimed at understanding the underlying biology of AD. The National Institutes of Health, for instance, “is interested in dupilumab and its impact on the skin barrier and skin defense mechanisms,” he said. “We’ll learn a lot more [in coming years].”
Spillover to other diseases
JAK inhibitors – some in oral and some in topical form – are showing efficacy in ongoing research for alopecia areata (AA) and vitiligo as well, Dr. Blauvelt said.
“We’re understanding more about the pathophysiology of these diseases, which historically have been tough diseases for dermatologists to treat,” he said. “The successes in alopecia areata and vitiligo are incredibly exciting actually – it’s very exciting to see hair and pigment coming back. And as we learn more, we should be able to develop [additional] drugs that are more disease targeted than the JAK inhibitors.”
Already, some of the biologics used to treat psoriasis have been studied in patients with hidradenitis suppurativa (HS), a disease in which painful lumps and sometimes tunnels form under the skin, with some success; adalimumab (Humira), a TNF-inhibitor, is now FDA approved for the treatment of moderate-severe HS, and studies are ongoing of IL-17 and IL-23 blockers for the disease.
“The pathophysiology [of HS] is very complex; it’s not nearly as straightforward as psoriasis, and there haven’t been any major breakthroughs yet,” Dr. Blauvelt said. “But the drugs seem to be working better than historical alternatives.”
Regarding AA, Dr. Guttman-Yassky, who is participating in a study of dupilumab for AA, recently found in a retrospective cross-sectional study that patients with the condition are more likely to have atopic comorbidities – asthma, allergic rhinitis, and AD, for instance. “The more comorbid conditions, the greater the risk of developing alopecia areata,” she said. “That could point to a potential pathogenic role of the Th2 axis in the disorder [challenging the traditional view of AA as a singularly Th1-centered disease.] The future will tell.”
Action on rare skin diseases
Both large and small companies have moved into the orphan drug space, investing in research and pursuing orphan drug indications for dermatologic conditions, because “it’s clear now in the marketplace that companies can develop effective drugs for rare disorders and be quite successful,” Dr. Orlow said.
According to a recent analysis, as a result of incentives for rare disease drug development contained in the Orphan Drug Act, 72 indications have been approved for rare skin disease, skin-related cancers, and hereditary disorders with prominent dermatologic manifestations since the law was passed in 1983 (J. Am. Acad. Dermatol. 2019;81[3]:867-77).
Epidermolysis bullosa (EB) is a good example, he and other sources said, of commercial interests merging with growing knowledge of disease pathogenesis as well as the tools needed to develop new treatments.
Research by dermatology scientists and others over the past 40 years, Dr. Ju explained, shed light on the molecular basis underlying the structure and function of the junction between the epidermis and dermis, including the pivotal role that type VII collagen plays in the normal adhesion of these two layers. Researchers then learned that, in EB, the family of genetic diseases characterized by skin fragility, “dystrophic types are caused by mutations in the gene encoding type VII collagen,” he said.
“Just as the advent of monoclonal antibodies allowed us to start attacking psoriasis and atopic dermatitis in unprecedented ways, the advent of gene therapy allows us to potentially address the fundamental molecular genetic defect of various types of EB,” Dr. Ju said.
While gene therapy is “still in its infancy,” companies have begun using the tools to address EB. One gene therapy in the pipeline – in phase 3 clinical trial testing – involves grafting back into patients with recessive dystrophic EB their skin cells that have been genetically modified to produce a correct (nonmutated) type VII collagen, he said.
Basal cell nevus syndrome, or Gorlin syndrome, a rare disease in which patients develop a multitude of basal cell carcinoma tumors, is another example of a “dermatology first” approach, Dr. Ju said. Research identified a genetic mutation that causes the hedgehog signaling pathway to be inappropriately activated in the disease, and a drug, vismodegib, was developed to inhibit this pathway. The drug was initially approved for patients with metastatic basal cell cancer and types of advanced basal cell cancer, and is now being tested in cancers affecting other organs, he said.
Basal cell cancer “is a huge market, but it was really unrecognized in the past,” Dr. Eaglstein said. “Seeing drugs come to market for basal cell cancer – this wouldn’t have happened [decades ago].”
Dr. Ju has worked in the pharmaceutical industry; all other sources in this story have worked with pharmaceutical manufacturers of treatments that are being developed or have been approved to treat dermatologic diseases mentioned in this story. In addition to Dr. Ju, Dr. Eaglstein and Dr. Orlow are cofounders of the Advancing Innovation in Dermatology group; Dr. Orlow is a member of the program committee for the organization’s dermatology summit conference.
For much of the past 50 years, many of the drugs used in dermatology have been adopted – and often adapted – from other specialties and used for dermatologic conditions.
“Almost every drug was more or less a hand-me-down” developed first for cancer or other diseases and found later, often serendipitously, to be useful for the skin, said William Eaglstein, MD, thinking back to the 1970s and recalling steroids, tetracyclines, methotrexate, and 5-flourouracil. “The perception always was that skin diseases weren’t serious, that the market was small.”
Much has changed. by dermatologist investigators, and “more and more companies are recognizing the importance of our diseases and the ability to get a return on investment,” said Dr. Eaglstein, past professor and chair of the departments of dermatology at the University of Miami and the University of Pittsburgh, who worked in industry after his academic career.
Psoriasis was a game changer, he and other dermatologists said in interviews. The tumor necrosis factor (TNF)–alpha blockers were first used for other indications, but their marked follow-on success in psoriasis “offered proof of concept clinically – showing that by targeting immune pathways in the skin we could achieve a clinical effect – and proof of concept commercially” that dermatology drugs are worth pursuing by pharmaceutical companies, said William Ju, MD, a cofounder and president of Advancing Innovation in Dermatology, a nonprofit organization that brings together stakeholders to develop novel dermatologic drugs and products.
This resulted in the approval of subsequent biologics, such as ustekinumab (Stelara) which inhibits the signaling of interleukin (IL)–12/IL-23, for psoriasis as their initial indication. Then, biologics targeting IL-17 followed this dermatology-first approach. “Researchers have continued further dissecting out the immunopathological pathways, and antibody drugs targeting IL-23p19 have been approved for psoriasis as the lead indication,” said Dr. Ju, a dermatologist who has worked in industry.
Seth Orlow, MD, PhD, who chairs the department of dermatology at NYU Langone Health, remembers the 1970s through the 1990s as the “era of topicals” developed for dermatologic conditions – topical antifungals, topical corticosteroids, and topical retinoids. The next decade was characterized by formulation tweaks and few novel treatments for dermatology, said Dr. Orlow, who is also professor of pediatric dermatology and director of the program in cutaneous biology at New York University.
Now, given the succession of psoriasis discoveries in the last decade, “large companies are interested in dermatology,” he said in an interview. “There’s an explosion of interest in atopic dermatitis. … and companies are dipping their toes in the water for alopecia areata and vitiligo. That’s amazing.”
Rare diseases like epidermolysis bullosa, ichthyosis, and basal cell nevus syndrome are getting attention as well, boosted by the Orphan Drug Act of 1983, in addition to increased research on disease pathways and growing appreciation of skin diseases. “There’s a lot under development, from small molecules to biologics to gene-based therapies,” Dr. Orlow commented.
The new frontier of atopic dermatitis
The approval in 2017 of dupilumab (Dupixent), a monoclonal antibody that inhibits the signaling of both IL-4 and IL-13) for moderate-severe atopic dermatitis (AD) in adults illustrates the new standing of dermatologic diseases in the field of drug development and commercialization. “Atopic dermatitis had always been the forgotten chronic disease in dermatology. … We’ve had no good treatments,” said Eric Simpson, MD, professor of dermatology at Oregon Health & Science University, Portland. “Dupilumab coming to the forefront [as a dermatology-first indication] has changed the entire perspective of the field. … Everyone is now trying to find the next best drug.”
As with psoriasis, a targeted therapy for AD was made possible by the development in the 1990s of monoclonal antibody technology and the ensuing ability to create biologics that target specific molecules in the body – as well as bedside-to-bench research that homed in on the involvement of particular cytokines.
But there also is a “new understanding of the burden of the disease,” Dr. Simpson observed. In the last 5 years, he said, research funded by the National Eczema Association documented that AD “not only causes inflammation of the skin … but that it affects people at school and in the workplace, that people have multiple mental health comorbidities and skin infections, and that the disease profoundly affects the entire patient in ways that weren’t really recognized or appreciated.”
Having evolved in the footsteps of psoriasis, AD is at a higher starting point in terms of the safety and efficacy of its first biologic, sources said. On the other hand, AD is a much more complex and heterogeneous disease, and researchers are trying to determine which immune pathways and cytokines are most important – and in which populations.
“We’re at the beginning. We’re trying to figure out how to get 80% of patients clear or almost clear [as we can now with psoriasis biologics] rather than almost 40% [as in the dupilumab pivotal trials],” said Dr. Simpson, former cochair of the National Eczema Association’s scientific committee. Public data from ongoing phase 2 and 3 trials of other Th2 cytokine inhibitors suggest that 25%-45% of enrolled patients achieve high levels of clearance, he noted.
Emma Guttman-Yassky, MD, PhD, Sol and Clara Kest Professor and vice-chair for research in the department of dermatology at the Icahn School of Medicine at Mount Sinai, New York, said that AD’s heterogeneity involves “many factors, like ethnicity, age … and whether they have an atopic background such as asthma.”
Her research is showing, for instance, that AD in Asian and black patients is different than AD in European-American patients, and that the presence of comorbidities may well have treatment implications. She has also shown that children may have a different phenotype than adults, with greater activation of the Th17 axis that typifies psoriasis.
“For certain patients, we may need to target more than one pathway, or target a different pathway than the Th2 pathway. And treatment may be different in the setting of comorbidities,” said Dr. Guttman-Yassky, who is also director of the laboratory of inflammatory skin diseases at Mount Sinai. “We may think of one treatment – dupilumab, for example – for someone who has asthma and AD. But for patients who don’t have asthma and are Asian, for instance, or for children, we may need additional agents.”
Her research over the years on AD has taught her the importance of human studies over mouse model studies; it was in humans, she noted, that she and other investigators demonstrated “without doubt” that AD is an immune disease and not simply a barrier disease. The Th2 cytokine pathway appears to play the predominant role in AD, though “there still is a strong Th1 component,” she said.
“We’re in a better position to figure this out today [than in the past 20 or even 10 years],” said Dr. Guttman-Yassky, who recalls being told years ago that AD was a “dead end,” that it “would kill [her] career.” Given the evolution of science and the recognition of comorbidities and seriousness of dermatologic diseases, “the stars are aligned to get more [therapies] to these patients.”
Janus kinase (JAK) inhibitors are among these therapies. Three JAK inhibitors are in or have recently completed phase 3 studies for AD; two are currently approved for rheumatoid arthritis, and the other has been designed specifically for AD, Dr. Simpson pointed out. The drugs are oral small molecule drugs that block the JAK signaling pathways for certain proinflammatory cytokines.
“The JAK inhibitors are a real exciting story for dermatology,” he said. “Theoretically, by blocking more cytokines than biologics do, there could be some safety issues – that’s why we’re awaiting big phase 3 study results so we can figure out the risk-benefit balance and guide our patients as to which drug is best.”
Andrew Blauvelt, MD, MBA, president of Oregon Medical Research Center in Portland – a stand-alone dermatology clinical trial center founded in 1998 – likes to envision the evolution of drugs for dermatologic conditions as a funnel, with the most broad-acting drugs at the wide top of the funnel and the most targeted drugs at the bottom tip.
JAK inhibitors, he said, sit near the middle – more targeted and safer than cyclosporine and methotrexate, for instance, but not as targeted as the biologics now available for psoriasis and being developed for AD. “The oral medications that have been developed for psoriasis and those coming for AD are not quite as targeted to the disease,” he noted. “JAK inhibitors have great efficacy – it’s more a question of safety and being able to treat without causing collateral damage.”
Dr. Blauvelt expects the armamentarium of new drugs approved for AD to go from one (dupilumab) to seven within the next 2 years. This will include three new biologics and three new oral JAK inhibitors, he predicts. As the specialty sorts through and integrates these new drugs into practice, dermatologists will increasingly personalize treatment and will face the “nonscientific” challenge of the cost of new therapies and patient access to them, he noted.
In the meantime, said Dr. Simpson, recent drug discoveries have driven more non–pharmaceutical-funded translational research aimed at understanding the underlying biology of AD. The National Institutes of Health, for instance, “is interested in dupilumab and its impact on the skin barrier and skin defense mechanisms,” he said. “We’ll learn a lot more [in coming years].”
Spillover to other diseases
JAK inhibitors – some in oral and some in topical form – are showing efficacy in ongoing research for alopecia areata (AA) and vitiligo as well, Dr. Blauvelt said.
“We’re understanding more about the pathophysiology of these diseases, which historically have been tough diseases for dermatologists to treat,” he said. “The successes in alopecia areata and vitiligo are incredibly exciting actually – it’s very exciting to see hair and pigment coming back. And as we learn more, we should be able to develop [additional] drugs that are more disease targeted than the JAK inhibitors.”
Already, some of the biologics used to treat psoriasis have been studied in patients with hidradenitis suppurativa (HS), a disease in which painful lumps and sometimes tunnels form under the skin, with some success; adalimumab (Humira), a TNF-inhibitor, is now FDA approved for the treatment of moderate-severe HS, and studies are ongoing of IL-17 and IL-23 blockers for the disease.
“The pathophysiology [of HS] is very complex; it’s not nearly as straightforward as psoriasis, and there haven’t been any major breakthroughs yet,” Dr. Blauvelt said. “But the drugs seem to be working better than historical alternatives.”
Regarding AA, Dr. Guttman-Yassky, who is participating in a study of dupilumab for AA, recently found in a retrospective cross-sectional study that patients with the condition are more likely to have atopic comorbidities – asthma, allergic rhinitis, and AD, for instance. “The more comorbid conditions, the greater the risk of developing alopecia areata,” she said. “That could point to a potential pathogenic role of the Th2 axis in the disorder [challenging the traditional view of AA as a singularly Th1-centered disease.] The future will tell.”
Action on rare skin diseases
Both large and small companies have moved into the orphan drug space, investing in research and pursuing orphan drug indications for dermatologic conditions, because “it’s clear now in the marketplace that companies can develop effective drugs for rare disorders and be quite successful,” Dr. Orlow said.
According to a recent analysis, as a result of incentives for rare disease drug development contained in the Orphan Drug Act, 72 indications have been approved for rare skin disease, skin-related cancers, and hereditary disorders with prominent dermatologic manifestations since the law was passed in 1983 (J. Am. Acad. Dermatol. 2019;81[3]:867-77).
Epidermolysis bullosa (EB) is a good example, he and other sources said, of commercial interests merging with growing knowledge of disease pathogenesis as well as the tools needed to develop new treatments.
Research by dermatology scientists and others over the past 40 years, Dr. Ju explained, shed light on the molecular basis underlying the structure and function of the junction between the epidermis and dermis, including the pivotal role that type VII collagen plays in the normal adhesion of these two layers. Researchers then learned that, in EB, the family of genetic diseases characterized by skin fragility, “dystrophic types are caused by mutations in the gene encoding type VII collagen,” he said.
“Just as the advent of monoclonal antibodies allowed us to start attacking psoriasis and atopic dermatitis in unprecedented ways, the advent of gene therapy allows us to potentially address the fundamental molecular genetic defect of various types of EB,” Dr. Ju said.
While gene therapy is “still in its infancy,” companies have begun using the tools to address EB. One gene therapy in the pipeline – in phase 3 clinical trial testing – involves grafting back into patients with recessive dystrophic EB their skin cells that have been genetically modified to produce a correct (nonmutated) type VII collagen, he said.
Basal cell nevus syndrome, or Gorlin syndrome, a rare disease in which patients develop a multitude of basal cell carcinoma tumors, is another example of a “dermatology first” approach, Dr. Ju said. Research identified a genetic mutation that causes the hedgehog signaling pathway to be inappropriately activated in the disease, and a drug, vismodegib, was developed to inhibit this pathway. The drug was initially approved for patients with metastatic basal cell cancer and types of advanced basal cell cancer, and is now being tested in cancers affecting other organs, he said.
Basal cell cancer “is a huge market, but it was really unrecognized in the past,” Dr. Eaglstein said. “Seeing drugs come to market for basal cell cancer – this wouldn’t have happened [decades ago].”
Dr. Ju has worked in the pharmaceutical industry; all other sources in this story have worked with pharmaceutical manufacturers of treatments that are being developed or have been approved to treat dermatologic diseases mentioned in this story. In addition to Dr. Ju, Dr. Eaglstein and Dr. Orlow are cofounders of the Advancing Innovation in Dermatology group; Dr. Orlow is a member of the program committee for the organization’s dermatology summit conference.