The First International Cancer Immunotherapy Conference

An EBV-infected cell (green/red)

among uninfected cells (blue)

Image by Benjamin

Chaigne-Delalande

NEW YORK—Type 2 Epstein-Barr virus (EBV) tumors, such as Hodgkin and non-Hodgkin lymphomas, are challenging to treat with virus-specific T (VST) cells, according to researchers.

These lymphomas express a more restricted array of EBV antigens that are not particularly immunogenic.

Nevertheless, researchers are devising an approach using peptide mixtures to activate EBV VSTs for use in these patients.

Helen Heslop, MD, of Baylor College of Medicine in Houston, Texas, described this work at the inaugural CRI-CIMT-EATI-AACR International Immunotherapy of Cancer Conference. She also described the researchers’ efforts to create off-the-shelf VSTs.

Dr Heslop explained that, in addition to the more restricted array of EBV antigens, EBV-associated tumors often produce inhibitory cytokines that can impede the activity of T cells.

So the researchers devised a strategy to expand these low-frequency clones by stimulating responding T cells with dendritic cells genetically modified with an ADV viral vector to overexpress LMP1 and LMP2. After multiple stimulations, they obtained an autologous product from the patient.

The team then tested the cytotoxic T cells in 21 patients with relapsed disease and in 29 patients as adjuvant therapy after stem cell transplant (n=14) or chemotherapy (n=15).

In the adjuvant arm, all patients but 1 remain in remission up to 5 years later.

In the relapsed arm, 11 had a complete response (CR), 2 had a partial response (PR), and 8 had progressive disease within 2 to 8 weeks.

“Importantly, there was no toxicity,” Dr Heslop said. “[A]ll were heavily pretreated with multiple lines of therapy for lymphoma, so I think the response rate is encouraging.”

An alternative approach: Pepmix-activated EBV VSTs

Although the antitumor effects of the above approach were encouraging, “we had a very complex manufacturing methodology that we didn’t think was sufficiently scaleable and robust for clinical studies,” Dr Heslop said.

“We also thought there would be potential regulatory issues with live EBV virus and the adenoviral vector,” she added.

And the researchers were concerned about the competition from the EBV/Ad-LMP dominant antigens.

So they devised an alternative approach using peptide mixture (pepmix)-activated EBVSTs.

This approach used autologous monocyte-derived dendritic cells as the antigen-presenting cells for the first stimulation.

The researchers pulsed them with overlapping peptides derived from 4 EBV antigens expressed in the tumors (EBV-LMP1, LMP2, EBNA1, and BARF1). They then expanded and opsonized the cells with IL-7 and IL-15.

For the second stimulation, the team used the T cells pulsed with the peptides and a K562 line pulsed with co-stimulatory molecules. And this process took 23 days, as opposed to the 2-3 months with the previous product.

The researchers have treated 9 patients with these EBVSTs as adjuvant therapy after autologous stem cell transplant. All patients remain in remission.

They also treated 6 patients with active disease. Two are in CR, 2 are in PR, and 2 have progressed.

This trial is ongoing, but the researchers believe that targeting the more challenging type 2 latency tumors with autologous cells can overcome T-cell anergy by using IL-7 and IL-15.

“Obviously, we need more numbers to know what the range of response is,” Dr Heslop said, although, at this early stage, it appears pepmix-activated T cells can produce antitumor responses.

An EBV-infected cell (green/red)

among uninfected cells (blue)

Image by Benjamin

Chaigne-Delalande

NEW YORK—Type 2 Epstein-Barr virus (EBV) tumors, such as Hodgkin and non-Hodgkin lymphomas, are challenging to treat with virus-specific T (VST) cells, according to researchers.

These lymphomas express a more restricted array of EBV antigens that are not particularly immunogenic.

Nevertheless, researchers are devising an approach using peptide mixtures to activate EBV VSTs for use in these patients.

Helen Heslop, MD, of Baylor College of Medicine in Houston, Texas, described this work at the inaugural CRI-CIMT-EATI-AACR International Immunotherapy of Cancer Conference. She also described the researchers’ efforts to create off-the-shelf VSTs.

Dr Heslop explained that, in addition to the more restricted array of EBV antigens, EBV-associated tumors often produce inhibitory cytokines that can impede the activity of T cells.

So the researchers devised a strategy to expand these low-frequency clones by stimulating responding T cells with dendritic cells genetically modified with an ADV viral vector to overexpress LMP1 and LMP2. After multiple stimulations, they obtained an autologous product from the patient.

The team then tested the cytotoxic T cells in 21 patients with relapsed disease and in 29 patients as adjuvant therapy after stem cell transplant (n=14) or chemotherapy (n=15).

In the adjuvant arm, all patients but 1 remain in remission up to 5 years later.

In the relapsed arm, 11 had a complete response (CR), 2 had a partial response (PR), and 8 had progressive disease within 2 to 8 weeks.

“Importantly, there was no toxicity,” Dr Heslop said. “[A]ll were heavily pretreated with multiple lines of therapy for lymphoma, so I think the response rate is encouraging.”

An alternative approach: Pepmix-activated EBV VSTs

Although the antitumor effects of the above approach were encouraging, “we had a very complex manufacturing methodology that we didn’t think was sufficiently scaleable and robust for clinical studies,” Dr Heslop said.

“We also thought there would be potential regulatory issues with live EBV virus and the adenoviral vector,” she added.

And the researchers were concerned about the competition from the EBV/Ad-LMP dominant antigens.

So they devised an alternative approach using peptide mixture (pepmix)-activated EBVSTs.

This approach used autologous monocyte-derived dendritic cells as the antigen-presenting cells for the first stimulation.

The researchers pulsed them with overlapping peptides derived from 4 EBV antigens expressed in the tumors (EBV-LMP1, LMP2, EBNA1, and BARF1). They then expanded and opsonized the cells with IL-7 and IL-15.

For the second stimulation, the team used the T cells pulsed with the peptides and a K562 line pulsed with co-stimulatory molecules. And this process took 23 days, as opposed to the 2-3 months with the previous product.

The researchers have treated 9 patients with these EBVSTs as adjuvant therapy after autologous stem cell transplant. All patients remain in remission.

They also treated 6 patients with active disease. Two are in CR, 2 are in PR, and 2 have progressed.

This trial is ongoing, but the researchers believe that targeting the more challenging type 2 latency tumors with autologous cells can overcome T-cell anergy by using IL-7 and IL-15.

“Obviously, we need more numbers to know what the range of response is,” Dr Heslop said, although, at this early stage, it appears pepmix-activated T cells can produce antitumor responses.

An EBV-infected cell (green/red)

among uninfected cells (blue)

Image by Benjamin

Chaigne-Delalande

NEW YORK—Type 2 Epstein-Barr virus (EBV) tumors, such as Hodgkin and non-Hodgkin lymphomas, are challenging to treat with virus-specific T (VST) cells, according to researchers.

These lymphomas express a more restricted array of EBV antigens that are not particularly immunogenic.

Nevertheless, researchers are devising an approach using peptide mixtures to activate EBV VSTs for use in these patients.

Helen Heslop, MD, of Baylor College of Medicine in Houston, Texas, described this work at the inaugural CRI-CIMT-EATI-AACR International Immunotherapy of Cancer Conference. She also described the researchers’ efforts to create off-the-shelf VSTs.

Dr Heslop explained that, in addition to the more restricted array of EBV antigens, EBV-associated tumors often produce inhibitory cytokines that can impede the activity of T cells.

So the researchers devised a strategy to expand these low-frequency clones by stimulating responding T cells with dendritic cells genetically modified with an ADV viral vector to overexpress LMP1 and LMP2. After multiple stimulations, they obtained an autologous product from the patient.

The team then tested the cytotoxic T cells in 21 patients with relapsed disease and in 29 patients as adjuvant therapy after stem cell transplant (n=14) or chemotherapy (n=15).

In the adjuvant arm, all patients but 1 remain in remission up to 5 years later.

In the relapsed arm, 11 had a complete response (CR), 2 had a partial response (PR), and 8 had progressive disease within 2 to 8 weeks.

“Importantly, there was no toxicity,” Dr Heslop said. “[A]ll were heavily pretreated with multiple lines of therapy for lymphoma, so I think the response rate is encouraging.”

An alternative approach: Pepmix-activated EBV VSTs

Although the antitumor effects of the above approach were encouraging, “we had a very complex manufacturing methodology that we didn’t think was sufficiently scaleable and robust for clinical studies,” Dr Heslop said.

“We also thought there would be potential regulatory issues with live EBV virus and the adenoviral vector,” she added.

And the researchers were concerned about the competition from the EBV/Ad-LMP dominant antigens.

So they devised an alternative approach using peptide mixture (pepmix)-activated EBVSTs.

This approach used autologous monocyte-derived dendritic cells as the antigen-presenting cells for the first stimulation.

The researchers pulsed them with overlapping peptides derived from 4 EBV antigens expressed in the tumors (EBV-LMP1, LMP2, EBNA1, and BARF1). They then expanded and opsonized the cells with IL-7 and IL-15.

For the second stimulation, the team used the T cells pulsed with the peptides and a K562 line pulsed with co-stimulatory molecules. And this process took 23 days, as opposed to the 2-3 months with the previous product.

The researchers have treated 9 patients with these EBVSTs as adjuvant therapy after autologous stem cell transplant. All patients remain in remission.

They also treated 6 patients with active disease. Two are in CR, 2 are in PR, and 2 have progressed.

This trial is ongoing, but the researchers believe that targeting the more challenging type 2 latency tumors with autologous cells can overcome T-cell anergy by using IL-7 and IL-15.

“Obviously, we need more numbers to know what the range of response is,” Dr Heslop said, although, at this early stage, it appears pepmix-activated T cells can produce antitumor responses.

Helen Heslop, MD

Photo courtesy of Baylor

College of Medicine

NEW YORK—Researchers are creating virus-specific T cells (VST) to treat and prevent viral infections in patients who undergo hematopoietic stem cell transplant.

Thus far, the group has modified T cells with 5 viral vectors—Epstein-Barr virus (EBV), cytomegalovirus (CMV), adenovirus (ADV), BK virus (BKV), and human herpesvirus 6 (HHV6)—and are devising methods whereby these VSTs can be made readily available, off-the-shelf products.

Helen Heslop, MD, of Baylor College of Medicine in Houston, Texas, described the efforts of the Baylor research team at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

The team’s tri-virus and 5-virus VST approaches have been described previously. Here, we focus on the team’s efforts to create an off-the-shelf product.

A companion story describes the team’s VST approach to treating type 2 EBV-associated lymphomas.

Despite promising results with these earlier methodologies both as prophylaxis and treatment after stem cell transplant, problems existed with the approaches that would impede broader implementation of VSTs.

“Most of these initial methodologies were complex,” Dr Heslop said.

And even though the production time of the 5-virus VSTs is only 10 days, it does not allow for urgent use.

To solve this problem, the researchers are developing VSTs as off-the-shelf, third-party banked cells for patients who don’t have the time to wait for donor-specific cells to be made.

“The strategy here is that we make lines that are well-characterized but are HLA-restricted and tied to specific viruses,” Dr Heslop said.

The cells are then cryopreserved so that they’re available, and patients receive VSTs according to their HLA type and the line that has suitable activity for their infections.

“We initially evaluated this approach through a multicenter study sponsored by the NHLBI [National Heart, Lung, and Blood Institute],” Dr Heslop said.

Tri-virus approach

The researchers used the original tri-virus methodology, which was lengthy, “but, in this case, because the cells were already available, the time was not a major issue,” Dr Heslop said.

The team also made some new lines for donors with common alleles. In all, they had 32 lines available while the study was running.

They treated 50 patients: 23 received VSTs for CMV, 18 for ADV, and 9 for EBV.

One patient who had CMV colitis received the VSTs and had a complete response (CR), as evidenced by a normal endoscopy with no viral inclusions.

Another patient had EBV persistent after 6 doses of rituximab. One month after receiving the VST infusion, the patient had a CR, even though the cell line had only 1 class 2 allele. And the patient has sustained the CR for several years.

The overall response rate for the study is 74.0% at day 42 after infusion.

The response rate was not significantly different for each virus, Dr Heslop pointed out. Patients with CMV had a 73.9% response rate, those with EBV had a 66.7% response rate, and those with ADV had a 77.8% response rate.

“This is a little bit lower than with the donor-specific T cells, but I think it’s still a promising approach,” she added.

5-virus peptide mix

The researchers are now evaluating the more rapid, 5-virus peptide mix method for creating off-the-shelf VSTs.

This method replaced live viruses with overlapping peptide pools and added immunogenic antigens for 5 viruses, including BKV and HHV6. The process takes only 10 days to produce VSTs.

The team has identified a line for over 90% of the patients screened.

“That’s because we will accept a line that’s only matched at 1 HLA allele, as long as we have activity against the infecting virus through the shared allele,” Dr Heslop explained.

So they’re conducting a clinical trial using this method, and thus far, they have enrolled 22 patients. Sixteen patients have had 1 infusion, and 6 patients have had multiple infusions.

The 22 patients had 25 infections: 10 CMV, 10 BKV, 2 EBV, 2 ADV, and 1 HHV6.

The overall response rate is 88%. Nine of 10 responses in patients with BKV were partial because BK is difficult to clear from urine. However, the BK patients who had hemorrhagic cystitis all had symptomatic improvement.

Dr Heslop pointed out that these results are similar to those at other centers using EBV third-party T cells.

The initial third-party studies were done in Scotland and had a response rate of about 60%, which increased to around 80% in follow-up studies, where they characterized the T cells more extensively.

Both donor-specific and third-party VSTs have low toxicity, sustained response rates, and activity confirmed by studies in multiple centers.

Dr Heslop believes the rapid manufacturing methodologies will facilitate definitive clinical trials.

She said Cell Medica provided support for some of the trials with EBV tumors.

Helen Heslop, MD

Photo courtesy of Baylor

College of Medicine

NEW YORK—Researchers are creating virus-specific T cells (VST) to treat and prevent viral infections in patients who undergo hematopoietic stem cell transplant.

Thus far, the group has modified T cells with 5 viral vectors—Epstein-Barr virus (EBV), cytomegalovirus (CMV), adenovirus (ADV), BK virus (BKV), and human herpesvirus 6 (HHV6)—and are devising methods whereby these VSTs can be made readily available, off-the-shelf products.

Helen Heslop, MD, of Baylor College of Medicine in Houston, Texas, described the efforts of the Baylor research team at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

The team’s tri-virus and 5-virus VST approaches have been described previously. Here, we focus on the team’s efforts to create an off-the-shelf product.

A companion story describes the team’s VST approach to treating type 2 EBV-associated lymphomas.

Despite promising results with these earlier methodologies both as prophylaxis and treatment after stem cell transplant, problems existed with the approaches that would impede broader implementation of VSTs.

“Most of these initial methodologies were complex,” Dr Heslop said.

And even though the production time of the 5-virus VSTs is only 10 days, it does not allow for urgent use.

To solve this problem, the researchers are developing VSTs as off-the-shelf, third-party banked cells for patients who don’t have the time to wait for donor-specific cells to be made.

“The strategy here is that we make lines that are well-characterized but are HLA-restricted and tied to specific viruses,” Dr Heslop said.

The cells are then cryopreserved so that they’re available, and patients receive VSTs according to their HLA type and the line that has suitable activity for their infections.

“We initially evaluated this approach through a multicenter study sponsored by the NHLBI [National Heart, Lung, and Blood Institute],” Dr Heslop said.

Tri-virus approach

The researchers used the original tri-virus methodology, which was lengthy, “but, in this case, because the cells were already available, the time was not a major issue,” Dr Heslop said.

The team also made some new lines for donors with common alleles. In all, they had 32 lines available while the study was running.

They treated 50 patients: 23 received VSTs for CMV, 18 for ADV, and 9 for EBV.

One patient who had CMV colitis received the VSTs and had a complete response (CR), as evidenced by a normal endoscopy with no viral inclusions.

Another patient had EBV persistent after 6 doses of rituximab. One month after receiving the VST infusion, the patient had a CR, even though the cell line had only 1 class 2 allele. And the patient has sustained the CR for several years.

The overall response rate for the study is 74.0% at day 42 after infusion.

The response rate was not significantly different for each virus, Dr Heslop pointed out. Patients with CMV had a 73.9% response rate, those with EBV had a 66.7% response rate, and those with ADV had a 77.8% response rate.

“This is a little bit lower than with the donor-specific T cells, but I think it’s still a promising approach,” she added.

5-virus peptide mix

The researchers are now evaluating the more rapid, 5-virus peptide mix method for creating off-the-shelf VSTs.

This method replaced live viruses with overlapping peptide pools and added immunogenic antigens for 5 viruses, including BKV and HHV6. The process takes only 10 days to produce VSTs.

The team has identified a line for over 90% of the patients screened.

“That’s because we will accept a line that’s only matched at 1 HLA allele, as long as we have activity against the infecting virus through the shared allele,” Dr Heslop explained.

So they’re conducting a clinical trial using this method, and thus far, they have enrolled 22 patients. Sixteen patients have had 1 infusion, and 6 patients have had multiple infusions.

The 22 patients had 25 infections: 10 CMV, 10 BKV, 2 EBV, 2 ADV, and 1 HHV6.

The overall response rate is 88%. Nine of 10 responses in patients with BKV were partial because BK is difficult to clear from urine. However, the BK patients who had hemorrhagic cystitis all had symptomatic improvement.

Dr Heslop pointed out that these results are similar to those at other centers using EBV third-party T cells.

The initial third-party studies were done in Scotland and had a response rate of about 60%, which increased to around 80% in follow-up studies, where they characterized the T cells more extensively.

Both donor-specific and third-party VSTs have low toxicity, sustained response rates, and activity confirmed by studies in multiple centers.

Dr Heslop believes the rapid manufacturing methodologies will facilitate definitive clinical trials.

She said Cell Medica provided support for some of the trials with EBV tumors.

Helen Heslop, MD

Photo courtesy of Baylor

College of Medicine

NEW YORK—Researchers are creating virus-specific T cells (VST) to treat and prevent viral infections in patients who undergo hematopoietic stem cell transplant.

Thus far, the group has modified T cells with 5 viral vectors—Epstein-Barr virus (EBV), cytomegalovirus (CMV), adenovirus (ADV), BK virus (BKV), and human herpesvirus 6 (HHV6)—and are devising methods whereby these VSTs can be made readily available, off-the-shelf products.

Helen Heslop, MD, of Baylor College of Medicine in Houston, Texas, described the efforts of the Baylor research team at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

The team’s tri-virus and 5-virus VST approaches have been described previously. Here, we focus on the team’s efforts to create an off-the-shelf product.

A companion story describes the team’s VST approach to treating type 2 EBV-associated lymphomas.

Despite promising results with these earlier methodologies both as prophylaxis and treatment after stem cell transplant, problems existed with the approaches that would impede broader implementation of VSTs.

“Most of these initial methodologies were complex,” Dr Heslop said.

And even though the production time of the 5-virus VSTs is only 10 days, it does not allow for urgent use.

To solve this problem, the researchers are developing VSTs as off-the-shelf, third-party banked cells for patients who don’t have the time to wait for donor-specific cells to be made.

“The strategy here is that we make lines that are well-characterized but are HLA-restricted and tied to specific viruses,” Dr Heslop said.

The cells are then cryopreserved so that they’re available, and patients receive VSTs according to their HLA type and the line that has suitable activity for their infections.

“We initially evaluated this approach through a multicenter study sponsored by the NHLBI [National Heart, Lung, and Blood Institute],” Dr Heslop said.

Tri-virus approach

The researchers used the original tri-virus methodology, which was lengthy, “but, in this case, because the cells were already available, the time was not a major issue,” Dr Heslop said.

The team also made some new lines for donors with common alleles. In all, they had 32 lines available while the study was running.

They treated 50 patients: 23 received VSTs for CMV, 18 for ADV, and 9 for EBV.

One patient who had CMV colitis received the VSTs and had a complete response (CR), as evidenced by a normal endoscopy with no viral inclusions.

Another patient had EBV persistent after 6 doses of rituximab. One month after receiving the VST infusion, the patient had a CR, even though the cell line had only 1 class 2 allele. And the patient has sustained the CR for several years.

The overall response rate for the study is 74.0% at day 42 after infusion.

The response rate was not significantly different for each virus, Dr Heslop pointed out. Patients with CMV had a 73.9% response rate, those with EBV had a 66.7% response rate, and those with ADV had a 77.8% response rate.

“This is a little bit lower than with the donor-specific T cells, but I think it’s still a promising approach,” she added.

5-virus peptide mix

The researchers are now evaluating the more rapid, 5-virus peptide mix method for creating off-the-shelf VSTs.

This method replaced live viruses with overlapping peptide pools and added immunogenic antigens for 5 viruses, including BKV and HHV6. The process takes only 10 days to produce VSTs.

The team has identified a line for over 90% of the patients screened.

“That’s because we will accept a line that’s only matched at 1 HLA allele, as long as we have activity against the infecting virus through the shared allele,” Dr Heslop explained.

So they’re conducting a clinical trial using this method, and thus far, they have enrolled 22 patients. Sixteen patients have had 1 infusion, and 6 patients have had multiple infusions.

The 22 patients had 25 infections: 10 CMV, 10 BKV, 2 EBV, 2 ADV, and 1 HHV6.

The overall response rate is 88%. Nine of 10 responses in patients with BKV were partial because BK is difficult to clear from urine. However, the BK patients who had hemorrhagic cystitis all had symptomatic improvement.

Dr Heslop pointed out that these results are similar to those at other centers using EBV third-party T cells.

The initial third-party studies were done in Scotland and had a response rate of about 60%, which increased to around 80% in follow-up studies, where they characterized the T cells more extensively.

Both donor-specific and third-party VSTs have low toxicity, sustained response rates, and activity confirmed by studies in multiple centers.

Dr Heslop believes the rapid manufacturing methodologies will facilitate definitive clinical trials.

She said Cell Medica provided support for some of the trials with EBV tumors.

Ursula Seidel

NEW YORK—Researchers have developed a pharmaceutical-grade, third-generation, CD19-specific antibody that reduced minimal residual disease (MRD) in pediatric patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL).

This chimerized, Fc-optimized antibody—4G7SDIE—was used on a compassionate-need basis in 14 patients with relapsed or refractory BCP-ALL. Nine of the patients had prior stem cell transplants.

Ursula JE Seidel, a PhD candidate at University Children’s Hospital Tubingen in Germany, discussed early results with the new antibody (poster B144) during the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Patients received 4G7SDIE infusions ranging from 5 mg/m² to 50 mg/m² twice a week for a year or longer.

They rarely experienced fever, nausea, or headache, according to the investigators, and all had B-cell depletion.

“The good thing about this antibody is it has a very low toxicity profile,” Seidel noted.

Upon discontinuation of therapy, B-cell counts recovered rapidly to normal levels.

The researchers followed the patients for a median of 543 days after transplant (range, 208–1137) and a median of 720 days after administration of 4G7SDIE (range, 264–1115).

Nine of the 14 patients had a reduction in MRD by 1 log or more, 2 of whom were receiving additional therapy with tyrosine kinase inhibitors.

Five patients had a reduction in MRD below the quantifiable level, and 2 patients became MRD-negative.

Six patients relapsed, and 5 of them died from relapsed disease. Two patients died of sepsis or chemotoxicity while in complete molecular remission. And 6 patients remain in complete molecular remission.

Functional characterization of 4G7SDIE

Through analysis of cells from healthy volunteers and BCP-ALL blasts of untreated and treated patients, the researchers determined that 4G7SDIE mediates enhanced antibody‑dependent cellular cytotoxicity through its improved capability to recruit FcγRIIIa-bearing effector cells.

They identified natural killer cells and γδ T cells as the main effector cells. And they determined that the FcγRIIIa-V158F polymorphism did not influence the effect of 4G7SDIE-mediated antibody‑dependent cellular cytotoxicity.

The researchers believe that the promising anti-leukemic effects of 4G7SDIE both in vitro and in vivo call for additional exploration. They are currently planning a phase 1/2 study to further assess the therapeutic activity of 4G7SDIE.

Ursula Seidel

NEW YORK—Researchers have developed a pharmaceutical-grade, third-generation, CD19-specific antibody that reduced minimal residual disease (MRD) in pediatric patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL).

This chimerized, Fc-optimized antibody—4G7SDIE—was used on a compassionate-need basis in 14 patients with relapsed or refractory BCP-ALL. Nine of the patients had prior stem cell transplants.

Ursula JE Seidel, a PhD candidate at University Children’s Hospital Tubingen in Germany, discussed early results with the new antibody (poster B144) during the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Patients received 4G7SDIE infusions ranging from 5 mg/m² to 50 mg/m² twice a week for a year or longer.

They rarely experienced fever, nausea, or headache, according to the investigators, and all had B-cell depletion.

“The good thing about this antibody is it has a very low toxicity profile,” Seidel noted.

Upon discontinuation of therapy, B-cell counts recovered rapidly to normal levels.

The researchers followed the patients for a median of 543 days after transplant (range, 208–1137) and a median of 720 days after administration of 4G7SDIE (range, 264–1115).

Nine of the 14 patients had a reduction in MRD by 1 log or more, 2 of whom were receiving additional therapy with tyrosine kinase inhibitors.

Five patients had a reduction in MRD below the quantifiable level, and 2 patients became MRD-negative.

Six patients relapsed, and 5 of them died from relapsed disease. Two patients died of sepsis or chemotoxicity while in complete molecular remission. And 6 patients remain in complete molecular remission.

Functional characterization of 4G7SDIE

Through analysis of cells from healthy volunteers and BCP-ALL blasts of untreated and treated patients, the researchers determined that 4G7SDIE mediates enhanced antibody‑dependent cellular cytotoxicity through its improved capability to recruit FcγRIIIa-bearing effector cells.

They identified natural killer cells and γδ T cells as the main effector cells. And they determined that the FcγRIIIa-V158F polymorphism did not influence the effect of 4G7SDIE-mediated antibody‑dependent cellular cytotoxicity.

The researchers believe that the promising anti-leukemic effects of 4G7SDIE both in vitro and in vivo call for additional exploration. They are currently planning a phase 1/2 study to further assess the therapeutic activity of 4G7SDIE.

Ursula Seidel

NEW YORK—Researchers have developed a pharmaceutical-grade, third-generation, CD19-specific antibody that reduced minimal residual disease (MRD) in pediatric patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL).

This chimerized, Fc-optimized antibody—4G7SDIE—was used on a compassionate-need basis in 14 patients with relapsed or refractory BCP-ALL. Nine of the patients had prior stem cell transplants.

Ursula JE Seidel, a PhD candidate at University Children’s Hospital Tubingen in Germany, discussed early results with the new antibody (poster B144) during the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Patients received 4G7SDIE infusions ranging from 5 mg/m² to 50 mg/m² twice a week for a year or longer.

They rarely experienced fever, nausea, or headache, according to the investigators, and all had B-cell depletion.

“The good thing about this antibody is it has a very low toxicity profile,” Seidel noted.

Upon discontinuation of therapy, B-cell counts recovered rapidly to normal levels.

The researchers followed the patients for a median of 543 days after transplant (range, 208–1137) and a median of 720 days after administration of 4G7SDIE (range, 264–1115).

Nine of the 14 patients had a reduction in MRD by 1 log or more, 2 of whom were receiving additional therapy with tyrosine kinase inhibitors.

Five patients had a reduction in MRD below the quantifiable level, and 2 patients became MRD-negative.

Six patients relapsed, and 5 of them died from relapsed disease. Two patients died of sepsis or chemotoxicity while in complete molecular remission. And 6 patients remain in complete molecular remission.

Functional characterization of 4G7SDIE

Through analysis of cells from healthy volunteers and BCP-ALL blasts of untreated and treated patients, the researchers determined that 4G7SDIE mediates enhanced antibody‑dependent cellular cytotoxicity through its improved capability to recruit FcγRIIIa-bearing effector cells.

They identified natural killer cells and γδ T cells as the main effector cells. And they determined that the FcγRIIIa-V158F polymorphism did not influence the effect of 4G7SDIE-mediated antibody‑dependent cellular cytotoxicity.

The researchers believe that the promising anti-leukemic effects of 4G7SDIE both in vitro and in vivo call for additional exploration. They are currently planning a phase 1/2 study to further assess the therapeutic activity of 4G7SDIE.

Laurence Cooper, MD, PhD

Photo courtesy of MDACC

NEW YORK—Researchers have used a nonviral approach to create chimeric antigen receptor (CAR) T cells and tested these cells in safety trials.

Patients with advanced lymphoma or leukemia were infused with the nonvirally modified CD19-directed CAR T cells after autologous or allogeneic hematopoietic stem cell transplant (HSCT).

Eighty-six percent of autologous HSCT recipients were alive 24 months after infusion, and 53% of allogeneic HSCT recipients were alive with a median follow-up of 6.5 months.

“Gratifyingly, the patients have not demonstrated any acute or late toxicity to these CAR T-cell infusions,” said Laurence Cooper, MD, PhD, formerly of MD Anderson Cancer Center (MDACC) in Houston, Texas, and now with Ziopharm Oncology.

Dr Cooper presented these results at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Some of the technology he described was conducted at MDACC. Dr Cooper is currently a visiting scientist there and will continue to supervise the development of this technology.

Dr Cooper said the appeal of this nonviral approach, which is a modified Sleeping Beauty approach, “is it essentially avoids the complexity of making a virus, a lentivirus or a retrovirus, it can be done at quite low cost, and really allows for a nimbleness to this system.”

Using a simple blood draw of 200 cc of peripheral blood—the process does not require apheresis—the T cells can be expanded on a feeder cell layer and genetically reprogrammed.

Sleeping Beauty system

The researchers reprogrammed the T cells using a 2-plasmid Sleeping Beauty system, which is a transposon/transposase system.

The transposon DNA plasmid codes for the cargo load, which, in this case, is the CAR. At the same time, the transposase DNA plasmid is electroporated, “which is really the secret sauce of the transposition event,” Dr Cooper explained.

After electroporation, the transposon/transposase are co-cultured with K562-derived artificial antigen-presenting cells (aAPC) and expanded with the integrated transposon of K562-aAPC. In this case, CD19 is on the aAPC.

CD19 is co-expressed with other co-stimulatory molecules, CD86 and 4-1BB ligand.

In addition, the researchers added a molecule of interleukin 15 that’s sewn in frame to the Fc region of an immunoglobulin that then activates the T cell in the context of these co-stimulatory molecules.

The T cells that have stable integrants of the CAR grow out over time. And those that have transient expression of the CAR die by neglect.

“By day 14, most of the T cells have the CAR sewn into the genome and are stably expressed,” Dr Cooper said.

The CAR used for these safety trials at MDACC targets CD19 and uses mouse scFv held in frame with an immunoglobulin 4 Fc (IgG4Fc) stalk.

It’s tunneled through the T-cell membrane and has 2 costimulatory molecules, signal 1 delivered by phosphorylation of the immunoreceptor tyrosine-based activation motif in CD3ζ and signal 2 by the costimulatory domain CD28.

The researchers tested the CD19 CARs in 2 clinical settings—one with T cells that were patient-derived and infused after autologous HSCT, and the second with T cells that were derived from a third party and infused after allogeneic HSCT.

Infusion after autologous HSCT

The researchers first tried the CARs in 7 non-Hodgkin lymphoma patients who had an autologous HSCT. Their median age was 52 (range, 36-61).

Five patients received a starting CAR T-cell dose of 5x10⁸ cells/m², and 2 received 5x10⁹ cells/m².

Six patients (86%) remain alive and are in complete remission (CR) at a median follow-up of 24 months.

Infusion after allogeneic HSCT

The researchers expanded the investigation to a wider cohort of 19 patients who had undergone allogeneic HSCT.

Seventeen patients had advanced CD19-positive acute lymphoblastic leukemia, and 2 had non-Hodgkin lymphoma. Their median age was 35 (range, 21-56).

All patients were on graft-versus-host disease (GVHD) prophylaxis with tacrolimus at the time of CAR infusion. A subset of these allogeneic transplant patients had haploidentical donors rather than matched sibling donors.

Five patients received a CAR T-cell dose of 10⁶, 6 patients received 10⁷, 5 received 5x10⁷, and 3 received 5x10⁸ cells/m² based on recipient body surface area.

Fifty-eight percent of patients (11/19) achieved a CR, and 10 remain alive a median of 6.5 months after CAR T-cell infusion.

Three patients developed GVHD, 1 with steroid-refractory acute liver disease, 1 with grade 2 acute skin disease, and 1 with chronic limited skin disease. The incidence of GVHD was lower than historical controls at MDACC, Dr Cooper said.

“[G]ratifyingly, in this clinical setting of minimal disease, patients did not have any acute or late toxicity from these infusions,” he added.

And the rate of cytomegalovirus reactivation after CAR T-cell infusion was 24%, compared with 41% for patients after transplant at MDACC without CAR T-cell infusion.

Eight patients received haploidentical HSCT followed by CAR T-cell infusion, and 75% (6/8) remain in CR.

Persistence of infused T cells

The researchers used 2 forms of PCR—qPCR and droplet PCR—to map the fate of the CARs.

“Roughly speaking, for these patients, and this is in line with the literature, in terms of those T cells that are activated through CD28 in contrast to 4-1BB, these T cells are, on average, living about 28 or so days post-infusion,” Dr Cooper noted.

He said this is similar to results observed with CARs being tested at the National Cancer Institute and Memorial Sloan-Kettering Cancer Center.

Laurence Cooper, MD, PhD

Photo courtesy of MDACC

NEW YORK—Researchers have used a nonviral approach to create chimeric antigen receptor (CAR) T cells and tested these cells in safety trials.

Patients with advanced lymphoma or leukemia were infused with the nonvirally modified CD19-directed CAR T cells after autologous or allogeneic hematopoietic stem cell transplant (HSCT).

Eighty-six percent of autologous HSCT recipients were alive 24 months after infusion, and 53% of allogeneic HSCT recipients were alive with a median follow-up of 6.5 months.

“Gratifyingly, the patients have not demonstrated any acute or late toxicity to these CAR T-cell infusions,” said Laurence Cooper, MD, PhD, formerly of MD Anderson Cancer Center (MDACC) in Houston, Texas, and now with Ziopharm Oncology.

Dr Cooper presented these results at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Some of the technology he described was conducted at MDACC. Dr Cooper is currently a visiting scientist there and will continue to supervise the development of this technology.

Dr Cooper said the appeal of this nonviral approach, which is a modified Sleeping Beauty approach, “is it essentially avoids the complexity of making a virus, a lentivirus or a retrovirus, it can be done at quite low cost, and really allows for a nimbleness to this system.”

Using a simple blood draw of 200 cc of peripheral blood—the process does not require apheresis—the T cells can be expanded on a feeder cell layer and genetically reprogrammed.

Sleeping Beauty system

The researchers reprogrammed the T cells using a 2-plasmid Sleeping Beauty system, which is a transposon/transposase system.

The transposon DNA plasmid codes for the cargo load, which, in this case, is the CAR. At the same time, the transposase DNA plasmid is electroporated, “which is really the secret sauce of the transposition event,” Dr Cooper explained.

After electroporation, the transposon/transposase are co-cultured with K562-derived artificial antigen-presenting cells (aAPC) and expanded with the integrated transposon of K562-aAPC. In this case, CD19 is on the aAPC.

CD19 is co-expressed with other co-stimulatory molecules, CD86 and 4-1BB ligand.

In addition, the researchers added a molecule of interleukin 15 that’s sewn in frame to the Fc region of an immunoglobulin that then activates the T cell in the context of these co-stimulatory molecules.

The T cells that have stable integrants of the CAR grow out over time. And those that have transient expression of the CAR die by neglect.

“By day 14, most of the T cells have the CAR sewn into the genome and are stably expressed,” Dr Cooper said.

The CAR used for these safety trials at MDACC targets CD19 and uses mouse scFv held in frame with an immunoglobulin 4 Fc (IgG4Fc) stalk.

It’s tunneled through the T-cell membrane and has 2 costimulatory molecules, signal 1 delivered by phosphorylation of the immunoreceptor tyrosine-based activation motif in CD3ζ and signal 2 by the costimulatory domain CD28.

The researchers tested the CD19 CARs in 2 clinical settings—one with T cells that were patient-derived and infused after autologous HSCT, and the second with T cells that were derived from a third party and infused after allogeneic HSCT.

Infusion after autologous HSCT

The researchers first tried the CARs in 7 non-Hodgkin lymphoma patients who had an autologous HSCT. Their median age was 52 (range, 36-61).

Five patients received a starting CAR T-cell dose of 5x10⁸ cells/m², and 2 received 5x10⁹ cells/m².

Six patients (86%) remain alive and are in complete remission (CR) at a median follow-up of 24 months.

Infusion after allogeneic HSCT

The researchers expanded the investigation to a wider cohort of 19 patients who had undergone allogeneic HSCT.

Seventeen patients had advanced CD19-positive acute lymphoblastic leukemia, and 2 had non-Hodgkin lymphoma. Their median age was 35 (range, 21-56).

All patients were on graft-versus-host disease (GVHD) prophylaxis with tacrolimus at the time of CAR infusion. A subset of these allogeneic transplant patients had haploidentical donors rather than matched sibling donors.

Five patients received a CAR T-cell dose of 10⁶, 6 patients received 10⁷, 5 received 5x10⁷, and 3 received 5x10⁸ cells/m² based on recipient body surface area.

Fifty-eight percent of patients (11/19) achieved a CR, and 10 remain alive a median of 6.5 months after CAR T-cell infusion.

Three patients developed GVHD, 1 with steroid-refractory acute liver disease, 1 with grade 2 acute skin disease, and 1 with chronic limited skin disease. The incidence of GVHD was lower than historical controls at MDACC, Dr Cooper said.

“[G]ratifyingly, in this clinical setting of minimal disease, patients did not have any acute or late toxicity from these infusions,” he added.

And the rate of cytomegalovirus reactivation after CAR T-cell infusion was 24%, compared with 41% for patients after transplant at MDACC without CAR T-cell infusion.

Eight patients received haploidentical HSCT followed by CAR T-cell infusion, and 75% (6/8) remain in CR.

Persistence of infused T cells

The researchers used 2 forms of PCR—qPCR and droplet PCR—to map the fate of the CARs.

“Roughly speaking, for these patients, and this is in line with the literature, in terms of those T cells that are activated through CD28 in contrast to 4-1BB, these T cells are, on average, living about 28 or so days post-infusion,” Dr Cooper noted.

He said this is similar to results observed with CARs being tested at the National Cancer Institute and Memorial Sloan-Kettering Cancer Center.

Laurence Cooper, MD, PhD

Photo courtesy of MDACC

NEW YORK—Researchers have used a nonviral approach to create chimeric antigen receptor (CAR) T cells and tested these cells in safety trials.

Patients with advanced lymphoma or leukemia were infused with the nonvirally modified CD19-directed CAR T cells after autologous or allogeneic hematopoietic stem cell transplant (HSCT).

Eighty-six percent of autologous HSCT recipients were alive 24 months after infusion, and 53% of allogeneic HSCT recipients were alive with a median follow-up of 6.5 months.

“Gratifyingly, the patients have not demonstrated any acute or late toxicity to these CAR T-cell infusions,” said Laurence Cooper, MD, PhD, formerly of MD Anderson Cancer Center (MDACC) in Houston, Texas, and now with Ziopharm Oncology.

Dr Cooper presented these results at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Some of the technology he described was conducted at MDACC. Dr Cooper is currently a visiting scientist there and will continue to supervise the development of this technology.

Dr Cooper said the appeal of this nonviral approach, which is a modified Sleeping Beauty approach, “is it essentially avoids the complexity of making a virus, a lentivirus or a retrovirus, it can be done at quite low cost, and really allows for a nimbleness to this system.”

Using a simple blood draw of 200 cc of peripheral blood—the process does not require apheresis—the T cells can be expanded on a feeder cell layer and genetically reprogrammed.

Sleeping Beauty system

The researchers reprogrammed the T cells using a 2-plasmid Sleeping Beauty system, which is a transposon/transposase system.

The transposon DNA plasmid codes for the cargo load, which, in this case, is the CAR. At the same time, the transposase DNA plasmid is electroporated, “which is really the secret sauce of the transposition event,” Dr Cooper explained.

After electroporation, the transposon/transposase are co-cultured with K562-derived artificial antigen-presenting cells (aAPC) and expanded with the integrated transposon of K562-aAPC. In this case, CD19 is on the aAPC.

CD19 is co-expressed with other co-stimulatory molecules, CD86 and 4-1BB ligand.

In addition, the researchers added a molecule of interleukin 15 that’s sewn in frame to the Fc region of an immunoglobulin that then activates the T cell in the context of these co-stimulatory molecules.

The T cells that have stable integrants of the CAR grow out over time. And those that have transient expression of the CAR die by neglect.

“By day 14, most of the T cells have the CAR sewn into the genome and are stably expressed,” Dr Cooper said.

The CAR used for these safety trials at MDACC targets CD19 and uses mouse scFv held in frame with an immunoglobulin 4 Fc (IgG4Fc) stalk.

It’s tunneled through the T-cell membrane and has 2 costimulatory molecules, signal 1 delivered by phosphorylation of the immunoreceptor tyrosine-based activation motif in CD3ζ and signal 2 by the costimulatory domain CD28.

The researchers tested the CD19 CARs in 2 clinical settings—one with T cells that were patient-derived and infused after autologous HSCT, and the second with T cells that were derived from a third party and infused after allogeneic HSCT.

Infusion after autologous HSCT

The researchers first tried the CARs in 7 non-Hodgkin lymphoma patients who had an autologous HSCT. Their median age was 52 (range, 36-61).

Five patients received a starting CAR T-cell dose of 5x10⁸ cells/m², and 2 received 5x10⁹ cells/m².

Six patients (86%) remain alive and are in complete remission (CR) at a median follow-up of 24 months.

Infusion after allogeneic HSCT

The researchers expanded the investigation to a wider cohort of 19 patients who had undergone allogeneic HSCT.

Seventeen patients had advanced CD19-positive acute lymphoblastic leukemia, and 2 had non-Hodgkin lymphoma. Their median age was 35 (range, 21-56).

All patients were on graft-versus-host disease (GVHD) prophylaxis with tacrolimus at the time of CAR infusion. A subset of these allogeneic transplant patients had haploidentical donors rather than matched sibling donors.

Five patients received a CAR T-cell dose of 10⁶, 6 patients received 10⁷, 5 received 5x10⁷, and 3 received 5x10⁸ cells/m² based on recipient body surface area.

Fifty-eight percent of patients (11/19) achieved a CR, and 10 remain alive a median of 6.5 months after CAR T-cell infusion.

Three patients developed GVHD, 1 with steroid-refractory acute liver disease, 1 with grade 2 acute skin disease, and 1 with chronic limited skin disease. The incidence of GVHD was lower than historical controls at MDACC, Dr Cooper said.

“[G]ratifyingly, in this clinical setting of minimal disease, patients did not have any acute or late toxicity from these infusions,” he added.

And the rate of cytomegalovirus reactivation after CAR T-cell infusion was 24%, compared with 41% for patients after transplant at MDACC without CAR T-cell infusion.

Eight patients received haploidentical HSCT followed by CAR T-cell infusion, and 75% (6/8) remain in CR.

Persistence of infused T cells

The researchers used 2 forms of PCR—qPCR and droplet PCR—to map the fate of the CARs.

“Roughly speaking, for these patients, and this is in line with the literature, in terms of those T cells that are activated through CD28 in contrast to 4-1BB, these T cells are, on average, living about 28 or so days post-infusion,” Dr Cooper noted.

He said this is similar to results observed with CARs being tested at the National Cancer Institute and Memorial Sloan-Kettering Cancer Center.

Mette Hazenberg, MD, PhD

NEW YORK—Investigators have found that B cells may play a role in stimulating graft-versus-leukemia (GvL) responses in patients with acute myeloid leukemia (AML) who have undergone allogeneic hematopoietic stem cell transplant (HSCT).

The team created B cell lines from these patients, isolated AML-specific antibodies, and found that these antibodies can induce the death of AML cells through oncosis.

Oncosis is a non-apoptotic type of cell death that involves swelling and coagulation of the cytoplasm.

Mette Hazenberg, MD, PhD, from the Academic Medical Center in Amsterdam, The Netherlands, reported these findings at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference as poster B052.

The investigators cloned B cells from 3 high-risk AML patients who had a strong GvL response after HSCT.

The team transduced memory B cells from the patients’ peripheral blood using BCL-6 and BCL-xL. They then screened the B cells for those that produced antibodies that bound specifically to surface antigens on AML cell lines and blasts.

Six of the 15 AML antibodies retrieved from the patients bound specifically to snRNp200. In normal cells, snRNp200 is in the nucleus, but, in AML, it is exposed on the cell membrane.

The investigators then confirmed this by ELISA.

They found 7 of the 15 AML antibodies directly lysed AML blasts without the addition of effector cells or complement. Time-lapse images showed that cell death by the AML antibodies occurred rapidly, within minutes after incubation.

“The leukemia blasts popped like balloons,” Dr Hazenberg said.

The investigators confirmed that the antibodies induced cell death by oncosis and that oncosis occurred independently of temperature. The antibodies were cytotoxic at 4°C and 37°C.

Cytotoxicity of the antibodies could be blocked by the membrane stabilizer cytochalasin D but not by apoptosis inhibitors.

The team concluded that a potent GvL response could be mediated by these antibodies against tumor-associated antigens on AML cells.

Dr Hazenberg’s hope is that, at some point, these antibodies can be combined with chemotherapy—as is rituximab—so patients won’t need to undergo transplant.

Mette Hazenberg, MD, PhD

NEW YORK—Investigators have found that B cells may play a role in stimulating graft-versus-leukemia (GvL) responses in patients with acute myeloid leukemia (AML) who have undergone allogeneic hematopoietic stem cell transplant (HSCT).

The team created B cell lines from these patients, isolated AML-specific antibodies, and found that these antibodies can induce the death of AML cells through oncosis.

Oncosis is a non-apoptotic type of cell death that involves swelling and coagulation of the cytoplasm.

Mette Hazenberg, MD, PhD, from the Academic Medical Center in Amsterdam, The Netherlands, reported these findings at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference as poster B052.

The investigators cloned B cells from 3 high-risk AML patients who had a strong GvL response after HSCT.

The team transduced memory B cells from the patients’ peripheral blood using BCL-6 and BCL-xL. They then screened the B cells for those that produced antibodies that bound specifically to surface antigens on AML cell lines and blasts.

Six of the 15 AML antibodies retrieved from the patients bound specifically to snRNp200. In normal cells, snRNp200 is in the nucleus, but, in AML, it is exposed on the cell membrane.

The investigators then confirmed this by ELISA.

They found 7 of the 15 AML antibodies directly lysed AML blasts without the addition of effector cells or complement. Time-lapse images showed that cell death by the AML antibodies occurred rapidly, within minutes after incubation.

“The leukemia blasts popped like balloons,” Dr Hazenberg said.

The investigators confirmed that the antibodies induced cell death by oncosis and that oncosis occurred independently of temperature. The antibodies were cytotoxic at 4°C and 37°C.

Cytotoxicity of the antibodies could be blocked by the membrane stabilizer cytochalasin D but not by apoptosis inhibitors.

The team concluded that a potent GvL response could be mediated by these antibodies against tumor-associated antigens on AML cells.

Dr Hazenberg’s hope is that, at some point, these antibodies can be combined with chemotherapy—as is rituximab—so patients won’t need to undergo transplant.

Mette Hazenberg, MD, PhD

NEW YORK—Investigators have found that B cells may play a role in stimulating graft-versus-leukemia (GvL) responses in patients with acute myeloid leukemia (AML) who have undergone allogeneic hematopoietic stem cell transplant (HSCT).

The team created B cell lines from these patients, isolated AML-specific antibodies, and found that these antibodies can induce the death of AML cells through oncosis.

Oncosis is a non-apoptotic type of cell death that involves swelling and coagulation of the cytoplasm.

Mette Hazenberg, MD, PhD, from the Academic Medical Center in Amsterdam, The Netherlands, reported these findings at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference as poster B052.

The investigators cloned B cells from 3 high-risk AML patients who had a strong GvL response after HSCT.

The team transduced memory B cells from the patients’ peripheral blood using BCL-6 and BCL-xL. They then screened the B cells for those that produced antibodies that bound specifically to surface antigens on AML cell lines and blasts.

Six of the 15 AML antibodies retrieved from the patients bound specifically to snRNp200. In normal cells, snRNp200 is in the nucleus, but, in AML, it is exposed on the cell membrane.

The investigators then confirmed this by ELISA.

They found 7 of the 15 AML antibodies directly lysed AML blasts without the addition of effector cells or complement. Time-lapse images showed that cell death by the AML antibodies occurred rapidly, within minutes after incubation.

“The leukemia blasts popped like balloons,” Dr Hazenberg said.

The investigators confirmed that the antibodies induced cell death by oncosis and that oncosis occurred independently of temperature. The antibodies were cytotoxic at 4°C and 37°C.

Cytotoxicity of the antibodies could be blocked by the membrane stabilizer cytochalasin D but not by apoptosis inhibitors.

The team concluded that a potent GvL response could be mediated by these antibodies against tumor-associated antigens on AML cells.

Dr Hazenberg’s hope is that, at some point, these antibodies can be combined with chemotherapy—as is rituximab—so patients won’t need to undergo transplant.

Carl June, MD

Photo courtesy of the

University of Pennsylvania

NEW YORK—The 5-year follow-up of the phase 1 trial of CTL019 in relapsed or refractory chronic lymphoblastic leukemia (CLL) is allowing investigators to define more clearly who will respond to chimeric antigen receptor (CAR) T cells directed against CD19.

One thing investigators have determined is that persistence of the CARs is essential for long-term responses.

In the first 2 patients who achieved a complete remission (CR), CAR T cells persisted for more than 4 years. In addition, no patient in CR has relapsed to date.

Of the 14 patients enrolled in the trial, 4 (28%) achieved a CR, 4 (28%) achieved a partial response, and 6 (43%) had no response, for an overall response rate of 57%.

These results were recently published in Science Translational Medicine.

Carl June, MD, of the University of Pennsylvania in Philadelphia, shared some insights into the research with attendees at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Dr June explained that CTL019 is a CD19-directed single chain variable fragment with a 4-1BB signaling module that transduces T cells with a lentiviral vector. The technology was developed at the University of Pennsylvania and subsequently licensed to Novartis.

In the phase 1 trial of CTL019 in CLL, patients who achieved complete remission have very high levels of CARs—100% of the circulating T cells—but the non-responders don’t. The CARs engrafted in non-responders but did not proliferate.

“So the biomarker correlate of success is persistence and proliferation, in CLL at least,” Dr June said.

The investigators performed IGH next-generation sequencing and found no detectable CLL clones in the complete responders, including 1 patient at 3.5 years and another at 4 years post-infusion.

“There was no clinically evident disease in these patients,” Dr June said, “and so the responses are durable.”

The team also believes that at least a subset of the cells remains functional because the patients still had B-cell aplasia.

The investigators have not observed a CD19 loss in any CLL patient who responded.

“Patients who have gone into remission stay in remission,” Dr June added.

Kinetics of delayed CR

Dr June discussed in detail Patient 10, whose response was somewhat different from the other complete responders. Patient 10 achieved a CR, but the response was delayed. It took 51 days after infusion, compared to about 10 days in the other complete responders.

Patient 10 was initially scored as a failure at the 28-day evaluation. Eventually, he had marked improvement, and, by a year, he was in CR.

He required hospitalization for tumor lysis syndrome and treatment with tocilizumab for cytokine release syndrome.

Patient 10 had a single cell that investigators surmise could have been responsible for the tumor elimination.

“In fact, on day 28, when he still had tumor, his CARs were polyclonal,” Dr June said. “So we stained and isolated his CARs by sorting, and, at time of tumor elimination, he had descendants of 1 CAR.”

Nevertheless, Patient 10’s response is durable. He is now 81 years old and remains engrafted with CAR19 cells.

Investigators hypothesize that the kinetics and CAR proliferation were so different in Patient 10 because Tet2 was disrupted by the integration of the CAR into the intronic region.

“What we don’t know is whether Tet2 was a passenger or a driver here,” Dr June observed. “Did it actually aid the function of the CAR cells or was it just a marker?”

He noted that Tet2 has been shown in acute myeloid leukemia to increase stem cell renewal, “and it may well have done that in this patient.”

Carl June, MD

Photo courtesy of the

University of Pennsylvania

NEW YORK—The 5-year follow-up of the phase 1 trial of CTL019 in relapsed or refractory chronic lymphoblastic leukemia (CLL) is allowing investigators to define more clearly who will respond to chimeric antigen receptor (CAR) T cells directed against CD19.

One thing investigators have determined is that persistence of the CARs is essential for long-term responses.

In the first 2 patients who achieved a complete remission (CR), CAR T cells persisted for more than 4 years. In addition, no patient in CR has relapsed to date.

Of the 14 patients enrolled in the trial, 4 (28%) achieved a CR, 4 (28%) achieved a partial response, and 6 (43%) had no response, for an overall response rate of 57%.

These results were recently published in Science Translational Medicine.

Carl June, MD, of the University of Pennsylvania in Philadelphia, shared some insights into the research with attendees at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Dr June explained that CTL019 is a CD19-directed single chain variable fragment with a 4-1BB signaling module that transduces T cells with a lentiviral vector. The technology was developed at the University of Pennsylvania and subsequently licensed to Novartis.

In the phase 1 trial of CTL019 in CLL, patients who achieved complete remission have very high levels of CARs—100% of the circulating T cells—but the non-responders don’t. The CARs engrafted in non-responders but did not proliferate.

“So the biomarker correlate of success is persistence and proliferation, in CLL at least,” Dr June said.

The investigators performed IGH next-generation sequencing and found no detectable CLL clones in the complete responders, including 1 patient at 3.5 years and another at 4 years post-infusion.

“There was no clinically evident disease in these patients,” Dr June said, “and so the responses are durable.”

The team also believes that at least a subset of the cells remains functional because the patients still had B-cell aplasia.

The investigators have not observed a CD19 loss in any CLL patient who responded.

“Patients who have gone into remission stay in remission,” Dr June added.

Kinetics of delayed CR

Dr June discussed in detail Patient 10, whose response was somewhat different from the other complete responders. Patient 10 achieved a CR, but the response was delayed. It took 51 days after infusion, compared to about 10 days in the other complete responders.

Patient 10 was initially scored as a failure at the 28-day evaluation. Eventually, he had marked improvement, and, by a year, he was in CR.

He required hospitalization for tumor lysis syndrome and treatment with tocilizumab for cytokine release syndrome.

Patient 10 had a single cell that investigators surmise could have been responsible for the tumor elimination.

“In fact, on day 28, when he still had tumor, his CARs were polyclonal,” Dr June said. “So we stained and isolated his CARs by sorting, and, at time of tumor elimination, he had descendants of 1 CAR.”

Nevertheless, Patient 10’s response is durable. He is now 81 years old and remains engrafted with CAR19 cells.

Investigators hypothesize that the kinetics and CAR proliferation were so different in Patient 10 because Tet2 was disrupted by the integration of the CAR into the intronic region.

“What we don’t know is whether Tet2 was a passenger or a driver here,” Dr June observed. “Did it actually aid the function of the CAR cells or was it just a marker?”

He noted that Tet2 has been shown in acute myeloid leukemia to increase stem cell renewal, “and it may well have done that in this patient.”

Carl June, MD

Photo courtesy of the

University of Pennsylvania

NEW YORK—The 5-year follow-up of the phase 1 trial of CTL019 in relapsed or refractory chronic lymphoblastic leukemia (CLL) is allowing investigators to define more clearly who will respond to chimeric antigen receptor (CAR) T cells directed against CD19.

One thing investigators have determined is that persistence of the CARs is essential for long-term responses.

In the first 2 patients who achieved a complete remission (CR), CAR T cells persisted for more than 4 years. In addition, no patient in CR has relapsed to date.

Of the 14 patients enrolled in the trial, 4 (28%) achieved a CR, 4 (28%) achieved a partial response, and 6 (43%) had no response, for an overall response rate of 57%.

These results were recently published in Science Translational Medicine.

Carl June, MD, of the University of Pennsylvania in Philadelphia, shared some insights into the research with attendees at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

Dr June explained that CTL019 is a CD19-directed single chain variable fragment with a 4-1BB signaling module that transduces T cells with a lentiviral vector. The technology was developed at the University of Pennsylvania and subsequently licensed to Novartis.

In the phase 1 trial of CTL019 in CLL, patients who achieved complete remission have very high levels of CARs—100% of the circulating T cells—but the non-responders don’t. The CARs engrafted in non-responders but did not proliferate.

“So the biomarker correlate of success is persistence and proliferation, in CLL at least,” Dr June said.

The investigators performed IGH next-generation sequencing and found no detectable CLL clones in the complete responders, including 1 patient at 3.5 years and another at 4 years post-infusion.

“There was no clinically evident disease in these patients,” Dr June said, “and so the responses are durable.”

The team also believes that at least a subset of the cells remains functional because the patients still had B-cell aplasia.

The investigators have not observed a CD19 loss in any CLL patient who responded.

“Patients who have gone into remission stay in remission,” Dr June added.

Kinetics of delayed CR

Dr June discussed in detail Patient 10, whose response was somewhat different from the other complete responders. Patient 10 achieved a CR, but the response was delayed. It took 51 days after infusion, compared to about 10 days in the other complete responders.

Patient 10 was initially scored as a failure at the 28-day evaluation. Eventually, he had marked improvement, and, by a year, he was in CR.

He required hospitalization for tumor lysis syndrome and treatment with tocilizumab for cytokine release syndrome.

Patient 10 had a single cell that investigators surmise could have been responsible for the tumor elimination.

“In fact, on day 28, when he still had tumor, his CARs were polyclonal,” Dr June said. “So we stained and isolated his CARs by sorting, and, at time of tumor elimination, he had descendants of 1 CAR.”

Nevertheless, Patient 10’s response is durable. He is now 81 years old and remains engrafted with CAR19 cells.

Investigators hypothesize that the kinetics and CAR proliferation were so different in Patient 10 because Tet2 was disrupted by the integration of the CAR into the intronic region.

“What we don’t know is whether Tet2 was a passenger or a driver here,” Dr June observed. “Did it actually aid the function of the CAR cells or was it just a marker?”

He noted that Tet2 has been shown in acute myeloid leukemia to increase stem cell renewal, “and it may well have done that in this patient.”

 

 

Hannah Karlsson, PhD

 

NEW YORK—For the first time, according to researchers, chimeric antigen receptor (CAR) T-cell therapy has been tested in a clinical trial in Sweden.

Early results have shown the treatment can produce complete responses (CRs) in leukemia and lymphoma, although most patients ultimately progressed.

Hannah Karlsson, PhD, of Uppsala University in Sweden, presented data from the phase 1/2a trial of the third-generation CD19 CAR T-cell therapy (abstract A041*) at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

The trial is a collaboration between Uppsala University and Baylor College of Medicine and was funded by AFA Insurances AB and the Swedish Cancer Society.

“Third-generation CAR T cells are being tested in clinical trials for leukemia patients in the United States with success,” said senior study author Angelica Loskog, PhD, also of Uppsala University.

“[T]he main purpose of our clinical trial was to evaluate whether we could reproduce the successful results in leukemia patients in Sweden and to also test if patients with lymphoma will also respond to this treatment.”

So the investigators enrolled 13 patients, 11 of whom were evaluable for efficacy at 3 months after CAR T-cell infusion. All patients had relapsed or refractory, CD19-positive, B-cell disease.

Two patients had acute lymphoblastic leukemia (ALL), 2 had chronic lymphocytic leukemia (CLL), and 7 had lymphoma—3 with diffuse large B-cell lymphoma (DLBCL), 2 with mantle cell lymphoma (MCL), 1 with follicular lymphoma (FL)/DLBCL, and 1 with Burkitt lymphoma.

All of the lymphoma patients received chemotherapy before CAR T-cell infusion to shrink their tumors. Seven patients—3 with leukemia and 4 with lymphoma—received pre-conditioning with cyclophosphamide plus fludarabine to reduce their immunosuppressive cell counts.

The investigators used CAR T cells containing signaling domains from both CD28 and 4-1BB and manufactured using a gamma retrovirus.

Patients received a single infusion of the CAR T cells, 2 patients at a dose of 2 x 10⁷ cells/m², 4 at a dose of 1 x 10⁸ cells/m², and 5 at 2 x 10⁸ cells/m².

Response and toxicity

Six patients had achieved a CR at the time of evaluation.

One patient with DLBCL experienced mild cytokine release syndrome (CRS) before achieving CR. However, the patient relapsed after a second CRS occurred (after 3 months).

Another DLBCL patient achieved a CR prior to T-cell infusion and remained in CR for 6 months before progressing.

One CLL patient and another DLBCL patient responded prior to T-cell infusion and remained in CR for more than 3 months. The CLL patient was still in CR at the time of the meeting.

One of the ALL patients achieved a CR after transient central nervous system toxicity but relapsed at 3 months with CD19-negative ALL. The other ALL patient was in CR for more than a month after experiencing CRS but ultimately progressed.

One CLL patient and 2 MCL patients had all progressed by 3 months.

The FL/DLBCL patient progressed after 1 month, with mild CRS. And the patient with Burkitt lymphoma had major CRS and progressive disease.

The investigators noted that 5 of the 6 patients who received pre-conditioning treatment had initial CRs.

The team is now analyzing whether there is any correlation between the level of immunosuppressive cells and patient response.

*Information presented at the meeting differs from the abstract.

 

 

Hannah Karlsson, PhD

 

NEW YORK—For the first time, according to researchers, chimeric antigen receptor (CAR) T-cell therapy has been tested in a clinical trial in Sweden.

Early results have shown the treatment can produce complete responses (CRs) in leukemia and lymphoma, although most patients ultimately progressed.

Hannah Karlsson, PhD, of Uppsala University in Sweden, presented data from the phase 1/2a trial of the third-generation CD19 CAR T-cell therapy (abstract A041*) at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

The trial is a collaboration between Uppsala University and Baylor College of Medicine and was funded by AFA Insurances AB and the Swedish Cancer Society.

“Third-generation CAR T cells are being tested in clinical trials for leukemia patients in the United States with success,” said senior study author Angelica Loskog, PhD, also of Uppsala University.

“[T]he main purpose of our clinical trial was to evaluate whether we could reproduce the successful results in leukemia patients in Sweden and to also test if patients with lymphoma will also respond to this treatment.”

So the investigators enrolled 13 patients, 11 of whom were evaluable for efficacy at 3 months after CAR T-cell infusion. All patients had relapsed or refractory, CD19-positive, B-cell disease.

Two patients had acute lymphoblastic leukemia (ALL), 2 had chronic lymphocytic leukemia (CLL), and 7 had lymphoma—3 with diffuse large B-cell lymphoma (DLBCL), 2 with mantle cell lymphoma (MCL), 1 with follicular lymphoma (FL)/DLBCL, and 1 with Burkitt lymphoma.

All of the lymphoma patients received chemotherapy before CAR T-cell infusion to shrink their tumors. Seven patients—3 with leukemia and 4 with lymphoma—received pre-conditioning with cyclophosphamide plus fludarabine to reduce their immunosuppressive cell counts.

The investigators used CAR T cells containing signaling domains from both CD28 and 4-1BB and manufactured using a gamma retrovirus.

Patients received a single infusion of the CAR T cells, 2 patients at a dose of 2 x 10⁷ cells/m², 4 at a dose of 1 x 10⁸ cells/m², and 5 at 2 x 10⁸ cells/m².

Response and toxicity

Six patients had achieved a CR at the time of evaluation.

One patient with DLBCL experienced mild cytokine release syndrome (CRS) before achieving CR. However, the patient relapsed after a second CRS occurred (after 3 months).

Another DLBCL patient achieved a CR prior to T-cell infusion and remained in CR for 6 months before progressing.

One CLL patient and another DLBCL patient responded prior to T-cell infusion and remained in CR for more than 3 months. The CLL patient was still in CR at the time of the meeting.

One of the ALL patients achieved a CR after transient central nervous system toxicity but relapsed at 3 months with CD19-negative ALL. The other ALL patient was in CR for more than a month after experiencing CRS but ultimately progressed.

One CLL patient and 2 MCL patients had all progressed by 3 months.

The FL/DLBCL patient progressed after 1 month, with mild CRS. And the patient with Burkitt lymphoma had major CRS and progressive disease.

The investigators noted that 5 of the 6 patients who received pre-conditioning treatment had initial CRs.

The team is now analyzing whether there is any correlation between the level of immunosuppressive cells and patient response.

*Information presented at the meeting differs from the abstract.

 

 

Hannah Karlsson, PhD

 

NEW YORK—For the first time, according to researchers, chimeric antigen receptor (CAR) T-cell therapy has been tested in a clinical trial in Sweden.

Early results have shown the treatment can produce complete responses (CRs) in leukemia and lymphoma, although most patients ultimately progressed.

Hannah Karlsson, PhD, of Uppsala University in Sweden, presented data from the phase 1/2a trial of the third-generation CD19 CAR T-cell therapy (abstract A041*) at the inaugural CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference.

The trial is a collaboration between Uppsala University and Baylor College of Medicine and was funded by AFA Insurances AB and the Swedish Cancer Society.

“Third-generation CAR T cells are being tested in clinical trials for leukemia patients in the United States with success,” said senior study author Angelica Loskog, PhD, also of Uppsala University.

“[T]he main purpose of our clinical trial was to evaluate whether we could reproduce the successful results in leukemia patients in Sweden and to also test if patients with lymphoma will also respond to this treatment.”

So the investigators enrolled 13 patients, 11 of whom were evaluable for efficacy at 3 months after CAR T-cell infusion. All patients had relapsed or refractory, CD19-positive, B-cell disease.

Two patients had acute lymphoblastic leukemia (ALL), 2 had chronic lymphocytic leukemia (CLL), and 7 had lymphoma—3 with diffuse large B-cell lymphoma (DLBCL), 2 with mantle cell lymphoma (MCL), 1 with follicular lymphoma (FL)/DLBCL, and 1 with Burkitt lymphoma.

All of the lymphoma patients received chemotherapy before CAR T-cell infusion to shrink their tumors. Seven patients—3 with leukemia and 4 with lymphoma—received pre-conditioning with cyclophosphamide plus fludarabine to reduce their immunosuppressive cell counts.

The investigators used CAR T cells containing signaling domains from both CD28 and 4-1BB and manufactured using a gamma retrovirus.

Patients received a single infusion of the CAR T cells, 2 patients at a dose of 2 x 10⁷ cells/m², 4 at a dose of 1 x 10⁸ cells/m², and 5 at 2 x 10⁸ cells/m².

Response and toxicity

Six patients had achieved a CR at the time of evaluation.

One patient with DLBCL experienced mild cytokine release syndrome (CRS) before achieving CR. However, the patient relapsed after a second CRS occurred (after 3 months).

Another DLBCL patient achieved a CR prior to T-cell infusion and remained in CR for 6 months before progressing.

One CLL patient and another DLBCL patient responded prior to T-cell infusion and remained in CR for more than 3 months. The CLL patient was still in CR at the time of the meeting.

One of the ALL patients achieved a CR after transient central nervous system toxicity but relapsed at 3 months with CD19-negative ALL. The other ALL patient was in CR for more than a month after experiencing CRS but ultimately progressed.

One CLL patient and 2 MCL patients had all progressed by 3 months.

The FL/DLBCL patient progressed after 1 month, with mild CRS. And the patient with Burkitt lymphoma had major CRS and progressive disease.

The investigators noted that 5 of the 6 patients who received pre-conditioning treatment had initial CRs.

The team is now analyzing whether there is any correlation between the level of immunosuppressive cells and patient response.

*Information presented at the meeting differs from the abstract.