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Quizartinib boosts AML survival, regardless of SCT
The research shows that “FLT3 inhibitors are most effective in patients who are minimal residual disease (MRD) positive before allo-HCT,” first author Richard Schlenk, MD, of Heidelberg (Germany) University Hospital and the German Cancer Research Center, Heidelberg, said in an interview.
The findings are from a post-hoc analysis of the phase 3, multicenter QuANTUM-First trial, which involved patients with the FLT3-ITD mutation, who make up about a quarter of those with AML and who can have shorter survival and increased risk of relapse, compared with patients without the mutation. The current post-hoc analysis of the trial was presented at the European Hematology Association 2023 Congress.
The trial, published in April in The Lancet, showed significant benefits in newly diagnosed patients with FLT3-ITD AML who were treated with quizartinib and standard induction and consolidation therapy and then continued on quizartinib as monotherapy for up to 3 years.
In the trial, quizartinib, combined with standard cytarabine and anthracycline induction and standard cytarabine consolidation chemotherapy, and continued as monotherapy following consolidation, was associated with a significant improvement in overall survival versus placebo (median 31.9 months versus 15.1 months, respectively; hazard ratio, 0.776; P = .0324).
For the post hoc analysis of the trial, the authors sought to evaluate if the effects were observed regardless of whether or not allo-HCT was received – which may not be recommended when patients go into remission after the first round of chemotherapy. The issue is important, as efficacy of other targeted therapy with the FLT3 inhibitors has been associated with allo-HCT treatment.
“Midostaurin, for example is mostly effective if [the drug] is followed by allo-HCT, and much less effective [no significant improvement] without allo-HCT,” Dr. Schlenk said.
The authors also sought to evaluate the relationship between minimal residual disease (MRD) prior to allo-HCT in FLT3-ITD and overall survival.
For the trial, 539 patients, with a median age of 56 were randomized to quizartinib (n = 268) or placebo (n = 271), and 147 patients (54.9%) in the quizartinib arm and 150 (55.4%) in the placebo arm achieved complete remission after induction. The rates of incomplete hematologic recovery (CRi) were 16.8% and 9.6%, respectively.
Of those achieving complete remission, 57.1% of patients on quizartinib and 48.7% of those receiving placebo underwent allo-HCT in the first complete remission. The median time to allo-HCT in the two groups was 3.5 months with quizartinib and 3.3 months for placebo.
Following the completion of allo-HCT, 61 patients (72.6%) receiving quizartinib and 36 (49.3%) receiving placebo started 3 years of continuation monotherapy.
In addition, 115 patients received allo-HCT outside of CR1, including 60 on quizartinib and 55 on placebo.
After adjustment for factors including region, age, and white blood count, patients treated with quizartinib treatment had a significantly higher overall survival (HR, 0.770; P = .0284), as did those receiving allo-HCT in CR1 (HR, 0.424; P < .0001).
Furthermore, patients receiving quizartinib had a longer overall survival regardless of whether they received allo-HCT in CR1 or not.
Of note, quizartinib-treated patients who were MRD positive prior to their allo-HCT transplant had a longer overall survival versus placebo (HR, 0.471); as did those who were MRD negative (HR, 0.717), to a lesser degree.
There were no new safety signals identified among patients undergoing allo-HCT.
Of note, cytomegalovirus infection was more common in the quizartinib group (11.8%) versus placebo (5.5%), while decreased appetite was less common with quizartinib (2.9%) versus placebo (12.1%).
Asked by an audience member about any risk of graft-versus-host disease (GVHD), Dr. Schlenk noted that “no difference between the quizartinib and placebo arms has been observed in GVHD acute and chronic.”
He added that patients “appear to benefit more from quizartinib if they have higher allelic frequency versus lower, overall,” and that younger patients, in general, showed greater benefit from quizartinib versus those over 60.
In general, “we see that for patients receiving allo-HCT transplantation, it’s beneficial to be randomized in the quizartinib arm [while] patients who did not undergo allo-HCT in first complete remission benefit equally when treated with quizartinib versus placebo,” he said in presenting the findings at the EHA meeting.
“And irrespective of pre–allo-HCT MRD status, longer survival was observed in those treated with quizartinib versus placebo, but most benefit was observed in those who were MRD positive.”
Quizartinib was approved in Japan this year in combination with chemotherapy for patients with newly diagnosed AML whose tumors harbor FLT3-ITD mutations.
The drug was granted a priority review by the U.S. Food and Drug Administration in October 2022. While the target action date was in April, a new decision date of July 21, 2023, is expected.
The study was sponsored by Daiichi Sankyo. Dr. Schlenk reported relationships with Daiichi Sankyo and other companies.
The research shows that “FLT3 inhibitors are most effective in patients who are minimal residual disease (MRD) positive before allo-HCT,” first author Richard Schlenk, MD, of Heidelberg (Germany) University Hospital and the German Cancer Research Center, Heidelberg, said in an interview.
The findings are from a post-hoc analysis of the phase 3, multicenter QuANTUM-First trial, which involved patients with the FLT3-ITD mutation, who make up about a quarter of those with AML and who can have shorter survival and increased risk of relapse, compared with patients without the mutation. The current post-hoc analysis of the trial was presented at the European Hematology Association 2023 Congress.
The trial, published in April in The Lancet, showed significant benefits in newly diagnosed patients with FLT3-ITD AML who were treated with quizartinib and standard induction and consolidation therapy and then continued on quizartinib as monotherapy for up to 3 years.
In the trial, quizartinib, combined with standard cytarabine and anthracycline induction and standard cytarabine consolidation chemotherapy, and continued as monotherapy following consolidation, was associated with a significant improvement in overall survival versus placebo (median 31.9 months versus 15.1 months, respectively; hazard ratio, 0.776; P = .0324).
For the post hoc analysis of the trial, the authors sought to evaluate if the effects were observed regardless of whether or not allo-HCT was received – which may not be recommended when patients go into remission after the first round of chemotherapy. The issue is important, as efficacy of other targeted therapy with the FLT3 inhibitors has been associated with allo-HCT treatment.
“Midostaurin, for example is mostly effective if [the drug] is followed by allo-HCT, and much less effective [no significant improvement] without allo-HCT,” Dr. Schlenk said.
The authors also sought to evaluate the relationship between minimal residual disease (MRD) prior to allo-HCT in FLT3-ITD and overall survival.
For the trial, 539 patients, with a median age of 56 were randomized to quizartinib (n = 268) or placebo (n = 271), and 147 patients (54.9%) in the quizartinib arm and 150 (55.4%) in the placebo arm achieved complete remission after induction. The rates of incomplete hematologic recovery (CRi) were 16.8% and 9.6%, respectively.
Of those achieving complete remission, 57.1% of patients on quizartinib and 48.7% of those receiving placebo underwent allo-HCT in the first complete remission. The median time to allo-HCT in the two groups was 3.5 months with quizartinib and 3.3 months for placebo.
Following the completion of allo-HCT, 61 patients (72.6%) receiving quizartinib and 36 (49.3%) receiving placebo started 3 years of continuation monotherapy.
In addition, 115 patients received allo-HCT outside of CR1, including 60 on quizartinib and 55 on placebo.
After adjustment for factors including region, age, and white blood count, patients treated with quizartinib treatment had a significantly higher overall survival (HR, 0.770; P = .0284), as did those receiving allo-HCT in CR1 (HR, 0.424; P < .0001).
Furthermore, patients receiving quizartinib had a longer overall survival regardless of whether they received allo-HCT in CR1 or not.
Of note, quizartinib-treated patients who were MRD positive prior to their allo-HCT transplant had a longer overall survival versus placebo (HR, 0.471); as did those who were MRD negative (HR, 0.717), to a lesser degree.
There were no new safety signals identified among patients undergoing allo-HCT.
Of note, cytomegalovirus infection was more common in the quizartinib group (11.8%) versus placebo (5.5%), while decreased appetite was less common with quizartinib (2.9%) versus placebo (12.1%).
Asked by an audience member about any risk of graft-versus-host disease (GVHD), Dr. Schlenk noted that “no difference between the quizartinib and placebo arms has been observed in GVHD acute and chronic.”
He added that patients “appear to benefit more from quizartinib if they have higher allelic frequency versus lower, overall,” and that younger patients, in general, showed greater benefit from quizartinib versus those over 60.
In general, “we see that for patients receiving allo-HCT transplantation, it’s beneficial to be randomized in the quizartinib arm [while] patients who did not undergo allo-HCT in first complete remission benefit equally when treated with quizartinib versus placebo,” he said in presenting the findings at the EHA meeting.
“And irrespective of pre–allo-HCT MRD status, longer survival was observed in those treated with quizartinib versus placebo, but most benefit was observed in those who were MRD positive.”
Quizartinib was approved in Japan this year in combination with chemotherapy for patients with newly diagnosed AML whose tumors harbor FLT3-ITD mutations.
The drug was granted a priority review by the U.S. Food and Drug Administration in October 2022. While the target action date was in April, a new decision date of July 21, 2023, is expected.
The study was sponsored by Daiichi Sankyo. Dr. Schlenk reported relationships with Daiichi Sankyo and other companies.
The research shows that “FLT3 inhibitors are most effective in patients who are minimal residual disease (MRD) positive before allo-HCT,” first author Richard Schlenk, MD, of Heidelberg (Germany) University Hospital and the German Cancer Research Center, Heidelberg, said in an interview.
The findings are from a post-hoc analysis of the phase 3, multicenter QuANTUM-First trial, which involved patients with the FLT3-ITD mutation, who make up about a quarter of those with AML and who can have shorter survival and increased risk of relapse, compared with patients without the mutation. The current post-hoc analysis of the trial was presented at the European Hematology Association 2023 Congress.
The trial, published in April in The Lancet, showed significant benefits in newly diagnosed patients with FLT3-ITD AML who were treated with quizartinib and standard induction and consolidation therapy and then continued on quizartinib as monotherapy for up to 3 years.
In the trial, quizartinib, combined with standard cytarabine and anthracycline induction and standard cytarabine consolidation chemotherapy, and continued as monotherapy following consolidation, was associated with a significant improvement in overall survival versus placebo (median 31.9 months versus 15.1 months, respectively; hazard ratio, 0.776; P = .0324).
For the post hoc analysis of the trial, the authors sought to evaluate if the effects were observed regardless of whether or not allo-HCT was received – which may not be recommended when patients go into remission after the first round of chemotherapy. The issue is important, as efficacy of other targeted therapy with the FLT3 inhibitors has been associated with allo-HCT treatment.
“Midostaurin, for example is mostly effective if [the drug] is followed by allo-HCT, and much less effective [no significant improvement] without allo-HCT,” Dr. Schlenk said.
The authors also sought to evaluate the relationship between minimal residual disease (MRD) prior to allo-HCT in FLT3-ITD and overall survival.
For the trial, 539 patients, with a median age of 56 were randomized to quizartinib (n = 268) or placebo (n = 271), and 147 patients (54.9%) in the quizartinib arm and 150 (55.4%) in the placebo arm achieved complete remission after induction. The rates of incomplete hematologic recovery (CRi) were 16.8% and 9.6%, respectively.
Of those achieving complete remission, 57.1% of patients on quizartinib and 48.7% of those receiving placebo underwent allo-HCT in the first complete remission. The median time to allo-HCT in the two groups was 3.5 months with quizartinib and 3.3 months for placebo.
Following the completion of allo-HCT, 61 patients (72.6%) receiving quizartinib and 36 (49.3%) receiving placebo started 3 years of continuation monotherapy.
In addition, 115 patients received allo-HCT outside of CR1, including 60 on quizartinib and 55 on placebo.
After adjustment for factors including region, age, and white blood count, patients treated with quizartinib treatment had a significantly higher overall survival (HR, 0.770; P = .0284), as did those receiving allo-HCT in CR1 (HR, 0.424; P < .0001).
Furthermore, patients receiving quizartinib had a longer overall survival regardless of whether they received allo-HCT in CR1 or not.
Of note, quizartinib-treated patients who were MRD positive prior to their allo-HCT transplant had a longer overall survival versus placebo (HR, 0.471); as did those who were MRD negative (HR, 0.717), to a lesser degree.
There were no new safety signals identified among patients undergoing allo-HCT.
Of note, cytomegalovirus infection was more common in the quizartinib group (11.8%) versus placebo (5.5%), while decreased appetite was less common with quizartinib (2.9%) versus placebo (12.1%).
Asked by an audience member about any risk of graft-versus-host disease (GVHD), Dr. Schlenk noted that “no difference between the quizartinib and placebo arms has been observed in GVHD acute and chronic.”
He added that patients “appear to benefit more from quizartinib if they have higher allelic frequency versus lower, overall,” and that younger patients, in general, showed greater benefit from quizartinib versus those over 60.
In general, “we see that for patients receiving allo-HCT transplantation, it’s beneficial to be randomized in the quizartinib arm [while] patients who did not undergo allo-HCT in first complete remission benefit equally when treated with quizartinib versus placebo,” he said in presenting the findings at the EHA meeting.
“And irrespective of pre–allo-HCT MRD status, longer survival was observed in those treated with quizartinib versus placebo, but most benefit was observed in those who were MRD positive.”
Quizartinib was approved in Japan this year in combination with chemotherapy for patients with newly diagnosed AML whose tumors harbor FLT3-ITD mutations.
The drug was granted a priority review by the U.S. Food and Drug Administration in October 2022. While the target action date was in April, a new decision date of July 21, 2023, is expected.
The study was sponsored by Daiichi Sankyo. Dr. Schlenk reported relationships with Daiichi Sankyo and other companies.
FROM THE EHA 2023 CONGRESS
SCD, beta-thalassemia: CRISPR-based gene therapy `transformative’
Results from the prespecified interim analyses of the phase 3 CLIMB THAL-111 and CLIMB SCD-121 studies, presented at the European Hematology Association annual congress, show that patients with beta-thalassemia who received exa-cel were able to remain transfusion-free for up to 40.7 consecutive months, while in patients with sickle cell disease, the treatment likewise provided up to 36.5 months of freedom from vaso-occlusive crises.
The findings underscore that “exa-cel can provide a one-time, functional cure to patients with beta-thalassemia and sickle cell disease,” said coauthor Franco Locatelli, MD, of Catholic University of the Sacred Heart, Bambino Gesù Children’s Hospital, Rome.
In a comment, senior investigator Haydar Frangoul, MD, noted that, “with almost 4 years of follow-up on patients with beta-thalassemia and sickle cell disease, it appears that the benefit is holding.”
“The engraftment of our edited cells appears very stable over time. There is no reason to believe it will change,” said Dr. Frangoul, who is medical director of pediatric hematology/oncology, Sarah Cannon Center for Blood Cancer at The Children’s Hospital at TriStar Centennial, Nashville, Tenn.
Burden is high; current curative options have caveats
Patients with transfusion-dependent beta-thalassemia may require blood transfusions as often as every 2-5 weeks because of genetic mutations causing the absence of functional hemoglobin and subsequent depletions in red blood cells. And with hemoglobin being an iron-rich protein, patients are also at risk of an iron accumulation in the body, adding the possible need for uncomfortable iron chelation therapy to prevent organ damage.
The measures are burdensome, but the need is dire. Life expectancy in beta-thalassemia without them is only about 5 years.
With SCD, patients can face severe pain from vaso-occlusive crises as sickled red blood cells block blood flow, potentially causing hospitalization and complications including kidney failure or stroke.
A cure does already exist for both genetic disorders in the form of allogeneic stem cell transplantation. However, that option requires a matched related stem cell donor, and fewer than 20% of patients have accessibility to such donors.
Gene therapy
Gene therapy offers a potentially ideal alternative, providing a possible “functional cure” without the need for a donor, by instead harvesting patients’ cells, fixing the mutation and transferring them back to the patient.
The Food and Drug Administration already approved a first gene therapy, betibeglogene autotemcel (beti-cel), for children and adults with transfusion dependent beta-thalassemia, in August 2022.
While beti-cel utilizes a viral vector to insert functional copies of a modified gene into patients’ extracted hematopoietic stem cells before transfusing them back, exa-cel instead uses CRISPR-CAS9 technology to edit the gene, allowing the body to produce fetal hemoglobin, in an approach believed to be more precise and efficient.
“As we explain to patients, it’s a difference between gene addition, which is what beti-cel is, or gene editing, which is what exa-cel is,” Dr. Frangoul explained.
Phase 3 trial interim results
In investigating exa-cel for beta-thalassemia, the ongoing CLIMB THAL-111 has enrolled 48 patients with a mean baseline age of 20, with 16 between the ages of 12 and 18. Of the patients, 28 (58.3%) had severe genotypes of disease.
Among 27 patients who were evaluable for the study endpoints of the current interim analysis, 24 (88.9%), achieved the primary endpoint of maintaining a weighted average hemoglobin of at least 9 g/dL without the need for a transfusion for at least 12 months (P < .0001).
Patients who achieved the transfusion independence for at least 12 months remained transfusion-free for a mean duration of 20.5 months, with a range of 12.1-40.7 months.
Of 3 patients who did not achieve the 12-month transfusion-free endpoint, substantial reductions in transfusion volume were nevertheless achieved, of 70.3%, 79.6%, and 95.5%, among the 3.
And for the CLIMB SCD-121 trial of SCD, 35 participants have been dosed with exa-cel; in the primary efficacy set of 17 patients, 16 of the 17 (94.1%) achieved the primary endpoint of having no severe vaso-occlusive crises for at least 12 months (P < .0001).
All patients, however, achieved the secondary endpoint of being free from in-patient hospitalizations for severe vaso-occlusive crises for at least 12 months (P < .0001).
Patients who achieved freedom from vaso-occlusive crises for at least 12 months remained free of the events for a mean of 18.7 months, ranging from 13.1 months to 36.5 months.
Durability, patient-reported outcomes favorable
Importantly, in both studies, hemoglobin levels, as well as levels of the edited BCL11A alleles in bone marrow CD34+ and peripheral blood nucleated cells, showed sustained stability over time, indicating durable editing of the cells, Dr. Locatelli said.
In terms of patient-reported quality-of-life, measures significantly improved during both trials at 24 months of follow-up, with significant improvements on the EuroQol visual analog scale, Functional Assessment of Cancer Therapy–General, and the Bone Marrow Transplantation Subscale.
Safety results were consistent with those observed with myeloablative busulfan-based conditioning regimen and autologous transplantation procedures, with adverse events that were manageable.
In the beta-thalassemia study, two patients experienced serious adverse events that were determined to be related to exa-cel, including one patient having symptoms in the context of hemophagocytic lymphohistiocytosis.
For the other patient, the serious adverse events consisted of delayed engraftment and thrombocytopenia, each also considered related to busulfan. None of the patients with SCD had serious adverse events related to exa-cel.
All serious adverse events were resolved, with no reports of deaths, study discontinuations, or malignancies.
Potentially first ever CRISPR-based FDA approval
While CRISPR-CAS9 gene editing is being investigated in multiple other trials in humans for various disorders, to date none have received FDA approval, which would make an approval for exa-cel a landmark development.
The therapy is currently under review, and Dr. Frangoul said the FDA has stated that a decision on the indication for SCD is expected by Dec. 8, 2023, and for beta-thalassemia, by March 2024.
Commenting on the research, Raffaella Colombatti, MD, a pediatric hematologist-oncologist and assistant professor of pediatrics at the University of Padova (Italy), underscored the need for a better curative alternative.
“Unfortunately, the other curative option, bone marrow transplant, is not available for all candidates due to the lack of suitable donors,” Dr. Colombatti said in an interview.
“And, although there are promising results from alternative donors and new conditioning regimens, a further option for selected patients with sickle cell disease and thalassemia utilizing gene therapy and gene editing is needed.”
Caveats regarding gene therapy for the two diseases that still need consideration include: “long-term safety results are still not available and eligibility criteria still needs to be explored outside clinical trials,” she said.
Furthermore, “costs and sustainability are also an issue,” Dr. Colombatti added.
The price of gene therapy is not cheap. With beti-cel priced at more than $2 million for the treatment, its manufacturer, Bluebird Bio, has reportedly already indicated that it will not pursue marketing in Europe because of unfavorable reimbursement policies, and a similar high price is anticipated for exa-cel.
Overall, however, the findings bode well for groundbreaking improvements in treatment of the two red blood cell disorders, Michael J. Eckrich, MD, MPH, medical director of pediatric stem cell transplant & cellular therapy at Atrium Health Levine Children’s Hospital Cancer and Blood Disorders in Charlotte, N.C., said in an interview.
“I do think that this is transformative therapy and will change our approach for patients with severe sickle cell disease in need of transplant,” said Dr. Eckrich, who has also been an investigator on the research of exa-cel for sickle cell disease.
“It might not be hard to imagine, that with the progress in gene therapies and gene editing, that allogeneic transplant will soon become obsolete for patients with sickle cell disease and beta-thalassemia.”
Dr. Locatelli is on the advisory board for Vertex Pharma and the speaker’s bureau for BluebirdBio. Dr. Frangoul and Dr. Colombatti are or have been consultants for Vertex Pharma.
Results from the prespecified interim analyses of the phase 3 CLIMB THAL-111 and CLIMB SCD-121 studies, presented at the European Hematology Association annual congress, show that patients with beta-thalassemia who received exa-cel were able to remain transfusion-free for up to 40.7 consecutive months, while in patients with sickle cell disease, the treatment likewise provided up to 36.5 months of freedom from vaso-occlusive crises.
The findings underscore that “exa-cel can provide a one-time, functional cure to patients with beta-thalassemia and sickle cell disease,” said coauthor Franco Locatelli, MD, of Catholic University of the Sacred Heart, Bambino Gesù Children’s Hospital, Rome.
In a comment, senior investigator Haydar Frangoul, MD, noted that, “with almost 4 years of follow-up on patients with beta-thalassemia and sickle cell disease, it appears that the benefit is holding.”
“The engraftment of our edited cells appears very stable over time. There is no reason to believe it will change,” said Dr. Frangoul, who is medical director of pediatric hematology/oncology, Sarah Cannon Center for Blood Cancer at The Children’s Hospital at TriStar Centennial, Nashville, Tenn.
Burden is high; current curative options have caveats
Patients with transfusion-dependent beta-thalassemia may require blood transfusions as often as every 2-5 weeks because of genetic mutations causing the absence of functional hemoglobin and subsequent depletions in red blood cells. And with hemoglobin being an iron-rich protein, patients are also at risk of an iron accumulation in the body, adding the possible need for uncomfortable iron chelation therapy to prevent organ damage.
The measures are burdensome, but the need is dire. Life expectancy in beta-thalassemia without them is only about 5 years.
With SCD, patients can face severe pain from vaso-occlusive crises as sickled red blood cells block blood flow, potentially causing hospitalization and complications including kidney failure or stroke.
A cure does already exist for both genetic disorders in the form of allogeneic stem cell transplantation. However, that option requires a matched related stem cell donor, and fewer than 20% of patients have accessibility to such donors.
Gene therapy
Gene therapy offers a potentially ideal alternative, providing a possible “functional cure” without the need for a donor, by instead harvesting patients’ cells, fixing the mutation and transferring them back to the patient.
The Food and Drug Administration already approved a first gene therapy, betibeglogene autotemcel (beti-cel), for children and adults with transfusion dependent beta-thalassemia, in August 2022.
While beti-cel utilizes a viral vector to insert functional copies of a modified gene into patients’ extracted hematopoietic stem cells before transfusing them back, exa-cel instead uses CRISPR-CAS9 technology to edit the gene, allowing the body to produce fetal hemoglobin, in an approach believed to be more precise and efficient.
“As we explain to patients, it’s a difference between gene addition, which is what beti-cel is, or gene editing, which is what exa-cel is,” Dr. Frangoul explained.
Phase 3 trial interim results
In investigating exa-cel for beta-thalassemia, the ongoing CLIMB THAL-111 has enrolled 48 patients with a mean baseline age of 20, with 16 between the ages of 12 and 18. Of the patients, 28 (58.3%) had severe genotypes of disease.
Among 27 patients who were evaluable for the study endpoints of the current interim analysis, 24 (88.9%), achieved the primary endpoint of maintaining a weighted average hemoglobin of at least 9 g/dL without the need for a transfusion for at least 12 months (P < .0001).
Patients who achieved the transfusion independence for at least 12 months remained transfusion-free for a mean duration of 20.5 months, with a range of 12.1-40.7 months.
Of 3 patients who did not achieve the 12-month transfusion-free endpoint, substantial reductions in transfusion volume were nevertheless achieved, of 70.3%, 79.6%, and 95.5%, among the 3.
And for the CLIMB SCD-121 trial of SCD, 35 participants have been dosed with exa-cel; in the primary efficacy set of 17 patients, 16 of the 17 (94.1%) achieved the primary endpoint of having no severe vaso-occlusive crises for at least 12 months (P < .0001).
All patients, however, achieved the secondary endpoint of being free from in-patient hospitalizations for severe vaso-occlusive crises for at least 12 months (P < .0001).
Patients who achieved freedom from vaso-occlusive crises for at least 12 months remained free of the events for a mean of 18.7 months, ranging from 13.1 months to 36.5 months.
Durability, patient-reported outcomes favorable
Importantly, in both studies, hemoglobin levels, as well as levels of the edited BCL11A alleles in bone marrow CD34+ and peripheral blood nucleated cells, showed sustained stability over time, indicating durable editing of the cells, Dr. Locatelli said.
In terms of patient-reported quality-of-life, measures significantly improved during both trials at 24 months of follow-up, with significant improvements on the EuroQol visual analog scale, Functional Assessment of Cancer Therapy–General, and the Bone Marrow Transplantation Subscale.
Safety results were consistent with those observed with myeloablative busulfan-based conditioning regimen and autologous transplantation procedures, with adverse events that were manageable.
In the beta-thalassemia study, two patients experienced serious adverse events that were determined to be related to exa-cel, including one patient having symptoms in the context of hemophagocytic lymphohistiocytosis.
For the other patient, the serious adverse events consisted of delayed engraftment and thrombocytopenia, each also considered related to busulfan. None of the patients with SCD had serious adverse events related to exa-cel.
All serious adverse events were resolved, with no reports of deaths, study discontinuations, or malignancies.
Potentially first ever CRISPR-based FDA approval
While CRISPR-CAS9 gene editing is being investigated in multiple other trials in humans for various disorders, to date none have received FDA approval, which would make an approval for exa-cel a landmark development.
The therapy is currently under review, and Dr. Frangoul said the FDA has stated that a decision on the indication for SCD is expected by Dec. 8, 2023, and for beta-thalassemia, by March 2024.
Commenting on the research, Raffaella Colombatti, MD, a pediatric hematologist-oncologist and assistant professor of pediatrics at the University of Padova (Italy), underscored the need for a better curative alternative.
“Unfortunately, the other curative option, bone marrow transplant, is not available for all candidates due to the lack of suitable donors,” Dr. Colombatti said in an interview.
“And, although there are promising results from alternative donors and new conditioning regimens, a further option for selected patients with sickle cell disease and thalassemia utilizing gene therapy and gene editing is needed.”
Caveats regarding gene therapy for the two diseases that still need consideration include: “long-term safety results are still not available and eligibility criteria still needs to be explored outside clinical trials,” she said.
Furthermore, “costs and sustainability are also an issue,” Dr. Colombatti added.
The price of gene therapy is not cheap. With beti-cel priced at more than $2 million for the treatment, its manufacturer, Bluebird Bio, has reportedly already indicated that it will not pursue marketing in Europe because of unfavorable reimbursement policies, and a similar high price is anticipated for exa-cel.
Overall, however, the findings bode well for groundbreaking improvements in treatment of the two red blood cell disorders, Michael J. Eckrich, MD, MPH, medical director of pediatric stem cell transplant & cellular therapy at Atrium Health Levine Children’s Hospital Cancer and Blood Disorders in Charlotte, N.C., said in an interview.
“I do think that this is transformative therapy and will change our approach for patients with severe sickle cell disease in need of transplant,” said Dr. Eckrich, who has also been an investigator on the research of exa-cel for sickle cell disease.
“It might not be hard to imagine, that with the progress in gene therapies and gene editing, that allogeneic transplant will soon become obsolete for patients with sickle cell disease and beta-thalassemia.”
Dr. Locatelli is on the advisory board for Vertex Pharma and the speaker’s bureau for BluebirdBio. Dr. Frangoul and Dr. Colombatti are or have been consultants for Vertex Pharma.
Results from the prespecified interim analyses of the phase 3 CLIMB THAL-111 and CLIMB SCD-121 studies, presented at the European Hematology Association annual congress, show that patients with beta-thalassemia who received exa-cel were able to remain transfusion-free for up to 40.7 consecutive months, while in patients with sickle cell disease, the treatment likewise provided up to 36.5 months of freedom from vaso-occlusive crises.
The findings underscore that “exa-cel can provide a one-time, functional cure to patients with beta-thalassemia and sickle cell disease,” said coauthor Franco Locatelli, MD, of Catholic University of the Sacred Heart, Bambino Gesù Children’s Hospital, Rome.
In a comment, senior investigator Haydar Frangoul, MD, noted that, “with almost 4 years of follow-up on patients with beta-thalassemia and sickle cell disease, it appears that the benefit is holding.”
“The engraftment of our edited cells appears very stable over time. There is no reason to believe it will change,” said Dr. Frangoul, who is medical director of pediatric hematology/oncology, Sarah Cannon Center for Blood Cancer at The Children’s Hospital at TriStar Centennial, Nashville, Tenn.
Burden is high; current curative options have caveats
Patients with transfusion-dependent beta-thalassemia may require blood transfusions as often as every 2-5 weeks because of genetic mutations causing the absence of functional hemoglobin and subsequent depletions in red blood cells. And with hemoglobin being an iron-rich protein, patients are also at risk of an iron accumulation in the body, adding the possible need for uncomfortable iron chelation therapy to prevent organ damage.
The measures are burdensome, but the need is dire. Life expectancy in beta-thalassemia without them is only about 5 years.
With SCD, patients can face severe pain from vaso-occlusive crises as sickled red blood cells block blood flow, potentially causing hospitalization and complications including kidney failure or stroke.
A cure does already exist for both genetic disorders in the form of allogeneic stem cell transplantation. However, that option requires a matched related stem cell donor, and fewer than 20% of patients have accessibility to such donors.
Gene therapy
Gene therapy offers a potentially ideal alternative, providing a possible “functional cure” without the need for a donor, by instead harvesting patients’ cells, fixing the mutation and transferring them back to the patient.
The Food and Drug Administration already approved a first gene therapy, betibeglogene autotemcel (beti-cel), for children and adults with transfusion dependent beta-thalassemia, in August 2022.
While beti-cel utilizes a viral vector to insert functional copies of a modified gene into patients’ extracted hematopoietic stem cells before transfusing them back, exa-cel instead uses CRISPR-CAS9 technology to edit the gene, allowing the body to produce fetal hemoglobin, in an approach believed to be more precise and efficient.
“As we explain to patients, it’s a difference between gene addition, which is what beti-cel is, or gene editing, which is what exa-cel is,” Dr. Frangoul explained.
Phase 3 trial interim results
In investigating exa-cel for beta-thalassemia, the ongoing CLIMB THAL-111 has enrolled 48 patients with a mean baseline age of 20, with 16 between the ages of 12 and 18. Of the patients, 28 (58.3%) had severe genotypes of disease.
Among 27 patients who were evaluable for the study endpoints of the current interim analysis, 24 (88.9%), achieved the primary endpoint of maintaining a weighted average hemoglobin of at least 9 g/dL without the need for a transfusion for at least 12 months (P < .0001).
Patients who achieved the transfusion independence for at least 12 months remained transfusion-free for a mean duration of 20.5 months, with a range of 12.1-40.7 months.
Of 3 patients who did not achieve the 12-month transfusion-free endpoint, substantial reductions in transfusion volume were nevertheless achieved, of 70.3%, 79.6%, and 95.5%, among the 3.
And for the CLIMB SCD-121 trial of SCD, 35 participants have been dosed with exa-cel; in the primary efficacy set of 17 patients, 16 of the 17 (94.1%) achieved the primary endpoint of having no severe vaso-occlusive crises for at least 12 months (P < .0001).
All patients, however, achieved the secondary endpoint of being free from in-patient hospitalizations for severe vaso-occlusive crises for at least 12 months (P < .0001).
Patients who achieved freedom from vaso-occlusive crises for at least 12 months remained free of the events for a mean of 18.7 months, ranging from 13.1 months to 36.5 months.
Durability, patient-reported outcomes favorable
Importantly, in both studies, hemoglobin levels, as well as levels of the edited BCL11A alleles in bone marrow CD34+ and peripheral blood nucleated cells, showed sustained stability over time, indicating durable editing of the cells, Dr. Locatelli said.
In terms of patient-reported quality-of-life, measures significantly improved during both trials at 24 months of follow-up, with significant improvements on the EuroQol visual analog scale, Functional Assessment of Cancer Therapy–General, and the Bone Marrow Transplantation Subscale.
Safety results were consistent with those observed with myeloablative busulfan-based conditioning regimen and autologous transplantation procedures, with adverse events that were manageable.
In the beta-thalassemia study, two patients experienced serious adverse events that were determined to be related to exa-cel, including one patient having symptoms in the context of hemophagocytic lymphohistiocytosis.
For the other patient, the serious adverse events consisted of delayed engraftment and thrombocytopenia, each also considered related to busulfan. None of the patients with SCD had serious adverse events related to exa-cel.
All serious adverse events were resolved, with no reports of deaths, study discontinuations, or malignancies.
Potentially first ever CRISPR-based FDA approval
While CRISPR-CAS9 gene editing is being investigated in multiple other trials in humans for various disorders, to date none have received FDA approval, which would make an approval for exa-cel a landmark development.
The therapy is currently under review, and Dr. Frangoul said the FDA has stated that a decision on the indication for SCD is expected by Dec. 8, 2023, and for beta-thalassemia, by March 2024.
Commenting on the research, Raffaella Colombatti, MD, a pediatric hematologist-oncologist and assistant professor of pediatrics at the University of Padova (Italy), underscored the need for a better curative alternative.
“Unfortunately, the other curative option, bone marrow transplant, is not available for all candidates due to the lack of suitable donors,” Dr. Colombatti said in an interview.
“And, although there are promising results from alternative donors and new conditioning regimens, a further option for selected patients with sickle cell disease and thalassemia utilizing gene therapy and gene editing is needed.”
Caveats regarding gene therapy for the two diseases that still need consideration include: “long-term safety results are still not available and eligibility criteria still needs to be explored outside clinical trials,” she said.
Furthermore, “costs and sustainability are also an issue,” Dr. Colombatti added.
The price of gene therapy is not cheap. With beti-cel priced at more than $2 million for the treatment, its manufacturer, Bluebird Bio, has reportedly already indicated that it will not pursue marketing in Europe because of unfavorable reimbursement policies, and a similar high price is anticipated for exa-cel.
Overall, however, the findings bode well for groundbreaking improvements in treatment of the two red blood cell disorders, Michael J. Eckrich, MD, MPH, medical director of pediatric stem cell transplant & cellular therapy at Atrium Health Levine Children’s Hospital Cancer and Blood Disorders in Charlotte, N.C., said in an interview.
“I do think that this is transformative therapy and will change our approach for patients with severe sickle cell disease in need of transplant,” said Dr. Eckrich, who has also been an investigator on the research of exa-cel for sickle cell disease.
“It might not be hard to imagine, that with the progress in gene therapies and gene editing, that allogeneic transplant will soon become obsolete for patients with sickle cell disease and beta-thalassemia.”
Dr. Locatelli is on the advisory board for Vertex Pharma and the speaker’s bureau for BluebirdBio. Dr. Frangoul and Dr. Colombatti are or have been consultants for Vertex Pharma.
FROM EHA 2023
Gilteritinib maintenance reduces relapse in MRD+ AML
The research was presented at the European Hematology Association Hybrid Congress 2023.
For the study, AML patients with the most common form of mutation in the proto-oncogene fms-like tyrosine kinase 3 (FLT3), known as the internal tandem duplication (ITD), were randomized to 24 months of maintenance therapy with either the FLT3 inhibitor gilteritinib or placebo.
The trial did not meet its primary endpoint, as there was no significant difference in relapse-free survival (RFS) between those assigned to the active drug and those given placebo, and there was no difference in overall survival rates.
However, subgroup analysis revealed that FLT3/ITD AML patients who were MRD+ after transplant, which represented approximately half of the participants, experienced a significant 48% improvement in RFS with gilteritinib versus placebo, while no benefit was seen in MRD– patients.
While acknowledging that the trial did not meet its primary endpoint, presenter Mark J. Levis, MD, PhD, program leader, hematologic malignancies and bone marrow transplant program, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Baltimore, said it was nevertheless “a successful study.”
“We learned how to use these drugs and in whom,” he continued, adding: “No, not everybody needs and should get a FLT3 inhibitor post-transplant, but we can use this [MRD] assay to identify who.”
Consequently, Dr. Levis believes that gilteritinib “should be a standard of care for those who are MRD positive,” although the decision to use it “should be balanced against the potential for toxicity,” compared with not adding an additional treatment after HCT.
He told a press conference that “we’re going to certainly make sure that patients who are MRD positive get [gilteritinib],” although the MRD negative patients “are going to be more questionable,” especially because the assay that they used in the study is not “perfect.”
Dr. Levis also suggested that the trial did not meet its endpoint because of regional differences in the clinical practice, such as in the number of treatment cycles prior to HCT, the time to transplant, and the previous use of a FLT3 inhibitor, all of which may have skewed the findings.
“Everybody in the world is convinced that they’re the best transplanter,” he said, and yet “they all do it differently, and the heterogeneity is astounding.”
He added: “If we’d restricted everybody [to a] pretransplant regimen, I suspect we would have had a different result than what we’re getting here, but this is releasing the drug into the world and saying: ‘Here, transplant however you want, however it’s practiced in the real world. Tell us how this works.’ ”
Approached for comment, Claudio Brunstein, MD, PhD, vice-chair of the department of hematology and oncology in the Cleveland Clinic Taussig Cancer Institute, said that while there was “some disappointment” with the results, he was “not surprised” that the trial did not meet its primary endpoint.
He said in an interview that the patient population was not of “high enough risk” to demonstrate an overall difference between gilteritinib and placebo, although he conceded that it is “hard to get to high-risk patients in a timely way” and so conduct a trial with them.
As to the notion that variations in clinical practice could have been responsible, Dr. Brunstein pointed out that it was a randomized trial, so the issue would have applied equally to both sides.
He nevertheless believes that it is “a very important study,” and “just the fact that it was done in the context of a number of drugs coming and being approved by the [U.S. Food and Drug Administration] in AML is quite remarkable.”
This is especially the case given that “many centers are already using [gilteritinib] as off-label maintenance therapy.”
Dr. Brunstein added that it is “good news” that the drug was effective in MRD+ patients, as it shows “you can overcome that with maintenance therapy rather than keeping giving more and more chemotherapy, especially as there are patients you’re worried about giving more intensive chemotherapy to make them MRD negative.”
He pointed out, however, that the assay used in the trial was “research grade” and very sensitive to MRD and “is not available everywhere, so there is an adjustment that the community will have to do to in order to apply this data.”
“But for those who are more obviously MRD positive with less sensitive assays, gilteritinib is already something that can be used,” Dr. Brunstein said.
Presenting the findings, Dr. Levis stated: “We all know that patients with FLT3/ITD AML have a high risk of relapse and are routinely referred for transplant. And we know that the detection of measurable residual disease pretransplant is highly predictive of outcome post-transplant.”
He continued that FLT3 inhibitors are “routinely given as post-transplant maintenance ... based on some prior trials, mostly with sorafenib.”
“But uncertainty exists as to the broad applicability of these trials,” Dr. Levis said. Moreover, the use of sorafenib in this context is “off label and can be difficult to tolerate,” and “we know that most patients are cured with allogeneic transplant alone.”
Gilteritinib is already known to be well tolerated as a monotherapy, and was approved by the FDA for the treatment of adult patients with FLT3 mutation–positive relapsed or refractory AML in 2018.
The investigators therefore examined whether it would be beneficial as a post-HCT maintenance therapy in FLT3-ITD AML. Patients were required to be in morphologic remission after one or two courses of induction therapy, with Dr. Levis underlining: “We did not allow patients who had been salvaged onto the study.”
They subsequently had a marrow aspirate sample taken for MRD analysis before undergoing allogeneic transplant, with any conditioning regimen, donor, or graft-versus-host disease (GVHD) prophylaxis allowed.
Between 30 and 90 days later, patients with successful engraftment who were able to take oral medication were then randomized to 24 months of maintenance therapy with either gilteritinib or placebo.
Dr. Levis showed that, among 620 patients screened at 110 centers in 16 countries, 356 were randomized between Aug. 15, 2017, and July 8, 2020. The median age was 53 years, and 49% of gilteritinib patients and 48% of those given placebo were female.
He noted that there was a “fairly even global distribution” of patients from North America, Europe, and the Asia/Pacific region, and that 60% of patients underwent a myeloablative conditioning regimen. Approximately the same proportion had received an FLT3 inhibitor prior to HCT.
MRD positivity, assessed at a cell count of ≥ 10-6, was observed pre-HCT in 47% of patients in both treatment groups, and in 50% of gilteritinib patients and 51% of placebo patients at both pre- and post-transplant assessments.
The treatment regimen was completed by 52.8% of patients assigned to gilteritinib and 53.9% in the placebo arm. Dr. Levis said that 18.5% and 20.3% of patients, respectively, experienced a grade 3/4 treatment emergent acute GVHD event, while 32.6% and 21.5%, respectively, had a grade ≥ 3 treatment emergent infection.
He noted that “adverse events were clearly more common in the gilteritinib arm and often led to either dose reduction or interruption, or withdrawal of treatment.”
The most common grade ≥ 3 treatment emergent adverse event was a decrease in neutrophil count, seen in 24.7% of gilteritinib patients and 7.9% of those given placebo, followed by reduced platelet count, in 15.2% and 5.6%, respectively, and anemia, in 6.2% and 1.7%, respectively.
Turning to the efficacy outcomes, Dr. Levis reported that the trial did not meet its primary endpoint, with no significant difference in RFS between the gilteritinib and placebo arms, at a hazard ratio of 0.679 (P = .0518). There was also no significant difference in the key secondary objective of overall survival, at a hazard ratio of 0.846 (P = .4394).
However, Dr. Levis noted that there was a “clear difference in the benefit of gilteritinib by region,” and, “at every level,” MRD predicted a benefit from gilteritinib, which he said was a “big surprise” and “really leapt out in the subgroup analysis.”
He explained that the researchers used a modified version of a two-step assay that has been used in previous studies, and was able to detect MRD at a sensitivity of approximately 1x10-6. “In our study, 98% of participants had samples pre- and post-[transplant].”
Regardless of treatment arm, MRD positivity measured at that sensitivity was associated with a significant reduction in overall survival, at a hazard ratio versus MRD– status of 0.514 (P = .0025).
When stratifying the patients by MRD status, the researchers found that, among MRD+ participants, gilteritinib was associated with a significant improvement in RFS, at a hazard ratio versus placebo of 0.515 (P = .0065), while there was no significant difference in MRD– patients.
Stratifying the patients by their conditioning regimen prior to HCT also revealed differences, with those undergoing myeloablative conditioning having significantly greater overall survival than those who underwent reduced-intensity conditioning, at a hazard ratio for death of 0.529 (P = .0027).
Dr. Levis said there is “no surprise there,” and the result could reflect the selection of fitter, younger patients to undergo the more intensive regimen.
He then showed that MRD+ patients who had undergone myeloablative conditioning had better overall survival with gilteritinib than placebo, at a hazard ratio for death of 0.418 (P = .0087). Again, the difference disappeared when looking at MRD– patients.
“So conditioning doesn’t help you in the setting of MRD,” Dr. Levis said.
Finally, he took a deeper dive into the regional differences in outcomes, noting that patients in the Asia/Pacific region, where gilteritinib showed no benefit over placebo, “were 10 years younger” than those in other regions, “tended to get myeloablative conditioning, and hardly ever used FLT3 inhibitors.”
In contrast, North American patients, who experienced a significant gilteritinib benefit in terms of RFS, underwent HCT an average of 26 days earlier than those elsewhere, and received fewer courses of chemotherapy pre-HCT. Moreover, 93.5% received an FLT3 inhibitor pretransplant.
The study was funded by Astellas Pharma Global Development. Dr. Levis declares relationships with Abbvie, Amgen, Astellas, Bristol-Myers-Squibb, Daiichi-Sankyo, GlaxoSmithKline, Jazz, Menarini, Pfizer, Sumitomo-Dainippon, Syndax, Takeda. Dr. Brunstein declares no relevant relationships.
The research was presented at the European Hematology Association Hybrid Congress 2023.
For the study, AML patients with the most common form of mutation in the proto-oncogene fms-like tyrosine kinase 3 (FLT3), known as the internal tandem duplication (ITD), were randomized to 24 months of maintenance therapy with either the FLT3 inhibitor gilteritinib or placebo.
The trial did not meet its primary endpoint, as there was no significant difference in relapse-free survival (RFS) between those assigned to the active drug and those given placebo, and there was no difference in overall survival rates.
However, subgroup analysis revealed that FLT3/ITD AML patients who were MRD+ after transplant, which represented approximately half of the participants, experienced a significant 48% improvement in RFS with gilteritinib versus placebo, while no benefit was seen in MRD– patients.
While acknowledging that the trial did not meet its primary endpoint, presenter Mark J. Levis, MD, PhD, program leader, hematologic malignancies and bone marrow transplant program, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Baltimore, said it was nevertheless “a successful study.”
“We learned how to use these drugs and in whom,” he continued, adding: “No, not everybody needs and should get a FLT3 inhibitor post-transplant, but we can use this [MRD] assay to identify who.”
Consequently, Dr. Levis believes that gilteritinib “should be a standard of care for those who are MRD positive,” although the decision to use it “should be balanced against the potential for toxicity,” compared with not adding an additional treatment after HCT.
He told a press conference that “we’re going to certainly make sure that patients who are MRD positive get [gilteritinib],” although the MRD negative patients “are going to be more questionable,” especially because the assay that they used in the study is not “perfect.”
Dr. Levis also suggested that the trial did not meet its endpoint because of regional differences in the clinical practice, such as in the number of treatment cycles prior to HCT, the time to transplant, and the previous use of a FLT3 inhibitor, all of which may have skewed the findings.
“Everybody in the world is convinced that they’re the best transplanter,” he said, and yet “they all do it differently, and the heterogeneity is astounding.”
He added: “If we’d restricted everybody [to a] pretransplant regimen, I suspect we would have had a different result than what we’re getting here, but this is releasing the drug into the world and saying: ‘Here, transplant however you want, however it’s practiced in the real world. Tell us how this works.’ ”
Approached for comment, Claudio Brunstein, MD, PhD, vice-chair of the department of hematology and oncology in the Cleveland Clinic Taussig Cancer Institute, said that while there was “some disappointment” with the results, he was “not surprised” that the trial did not meet its primary endpoint.
He said in an interview that the patient population was not of “high enough risk” to demonstrate an overall difference between gilteritinib and placebo, although he conceded that it is “hard to get to high-risk patients in a timely way” and so conduct a trial with them.
As to the notion that variations in clinical practice could have been responsible, Dr. Brunstein pointed out that it was a randomized trial, so the issue would have applied equally to both sides.
He nevertheless believes that it is “a very important study,” and “just the fact that it was done in the context of a number of drugs coming and being approved by the [U.S. Food and Drug Administration] in AML is quite remarkable.”
This is especially the case given that “many centers are already using [gilteritinib] as off-label maintenance therapy.”
Dr. Brunstein added that it is “good news” that the drug was effective in MRD+ patients, as it shows “you can overcome that with maintenance therapy rather than keeping giving more and more chemotherapy, especially as there are patients you’re worried about giving more intensive chemotherapy to make them MRD negative.”
He pointed out, however, that the assay used in the trial was “research grade” and very sensitive to MRD and “is not available everywhere, so there is an adjustment that the community will have to do to in order to apply this data.”
“But for those who are more obviously MRD positive with less sensitive assays, gilteritinib is already something that can be used,” Dr. Brunstein said.
Presenting the findings, Dr. Levis stated: “We all know that patients with FLT3/ITD AML have a high risk of relapse and are routinely referred for transplant. And we know that the detection of measurable residual disease pretransplant is highly predictive of outcome post-transplant.”
He continued that FLT3 inhibitors are “routinely given as post-transplant maintenance ... based on some prior trials, mostly with sorafenib.”
“But uncertainty exists as to the broad applicability of these trials,” Dr. Levis said. Moreover, the use of sorafenib in this context is “off label and can be difficult to tolerate,” and “we know that most patients are cured with allogeneic transplant alone.”
Gilteritinib is already known to be well tolerated as a monotherapy, and was approved by the FDA for the treatment of adult patients with FLT3 mutation–positive relapsed or refractory AML in 2018.
The investigators therefore examined whether it would be beneficial as a post-HCT maintenance therapy in FLT3-ITD AML. Patients were required to be in morphologic remission after one or two courses of induction therapy, with Dr. Levis underlining: “We did not allow patients who had been salvaged onto the study.”
They subsequently had a marrow aspirate sample taken for MRD analysis before undergoing allogeneic transplant, with any conditioning regimen, donor, or graft-versus-host disease (GVHD) prophylaxis allowed.
Between 30 and 90 days later, patients with successful engraftment who were able to take oral medication were then randomized to 24 months of maintenance therapy with either gilteritinib or placebo.
Dr. Levis showed that, among 620 patients screened at 110 centers in 16 countries, 356 were randomized between Aug. 15, 2017, and July 8, 2020. The median age was 53 years, and 49% of gilteritinib patients and 48% of those given placebo were female.
He noted that there was a “fairly even global distribution” of patients from North America, Europe, and the Asia/Pacific region, and that 60% of patients underwent a myeloablative conditioning regimen. Approximately the same proportion had received an FLT3 inhibitor prior to HCT.
MRD positivity, assessed at a cell count of ≥ 10-6, was observed pre-HCT in 47% of patients in both treatment groups, and in 50% of gilteritinib patients and 51% of placebo patients at both pre- and post-transplant assessments.
The treatment regimen was completed by 52.8% of patients assigned to gilteritinib and 53.9% in the placebo arm. Dr. Levis said that 18.5% and 20.3% of patients, respectively, experienced a grade 3/4 treatment emergent acute GVHD event, while 32.6% and 21.5%, respectively, had a grade ≥ 3 treatment emergent infection.
He noted that “adverse events were clearly more common in the gilteritinib arm and often led to either dose reduction or interruption, or withdrawal of treatment.”
The most common grade ≥ 3 treatment emergent adverse event was a decrease in neutrophil count, seen in 24.7% of gilteritinib patients and 7.9% of those given placebo, followed by reduced platelet count, in 15.2% and 5.6%, respectively, and anemia, in 6.2% and 1.7%, respectively.
Turning to the efficacy outcomes, Dr. Levis reported that the trial did not meet its primary endpoint, with no significant difference in RFS between the gilteritinib and placebo arms, at a hazard ratio of 0.679 (P = .0518). There was also no significant difference in the key secondary objective of overall survival, at a hazard ratio of 0.846 (P = .4394).
However, Dr. Levis noted that there was a “clear difference in the benefit of gilteritinib by region,” and, “at every level,” MRD predicted a benefit from gilteritinib, which he said was a “big surprise” and “really leapt out in the subgroup analysis.”
He explained that the researchers used a modified version of a two-step assay that has been used in previous studies, and was able to detect MRD at a sensitivity of approximately 1x10-6. “In our study, 98% of participants had samples pre- and post-[transplant].”
Regardless of treatment arm, MRD positivity measured at that sensitivity was associated with a significant reduction in overall survival, at a hazard ratio versus MRD– status of 0.514 (P = .0025).
When stratifying the patients by MRD status, the researchers found that, among MRD+ participants, gilteritinib was associated with a significant improvement in RFS, at a hazard ratio versus placebo of 0.515 (P = .0065), while there was no significant difference in MRD– patients.
Stratifying the patients by their conditioning regimen prior to HCT also revealed differences, with those undergoing myeloablative conditioning having significantly greater overall survival than those who underwent reduced-intensity conditioning, at a hazard ratio for death of 0.529 (P = .0027).
Dr. Levis said there is “no surprise there,” and the result could reflect the selection of fitter, younger patients to undergo the more intensive regimen.
He then showed that MRD+ patients who had undergone myeloablative conditioning had better overall survival with gilteritinib than placebo, at a hazard ratio for death of 0.418 (P = .0087). Again, the difference disappeared when looking at MRD– patients.
“So conditioning doesn’t help you in the setting of MRD,” Dr. Levis said.
Finally, he took a deeper dive into the regional differences in outcomes, noting that patients in the Asia/Pacific region, where gilteritinib showed no benefit over placebo, “were 10 years younger” than those in other regions, “tended to get myeloablative conditioning, and hardly ever used FLT3 inhibitors.”
In contrast, North American patients, who experienced a significant gilteritinib benefit in terms of RFS, underwent HCT an average of 26 days earlier than those elsewhere, and received fewer courses of chemotherapy pre-HCT. Moreover, 93.5% received an FLT3 inhibitor pretransplant.
The study was funded by Astellas Pharma Global Development. Dr. Levis declares relationships with Abbvie, Amgen, Astellas, Bristol-Myers-Squibb, Daiichi-Sankyo, GlaxoSmithKline, Jazz, Menarini, Pfizer, Sumitomo-Dainippon, Syndax, Takeda. Dr. Brunstein declares no relevant relationships.
The research was presented at the European Hematology Association Hybrid Congress 2023.
For the study, AML patients with the most common form of mutation in the proto-oncogene fms-like tyrosine kinase 3 (FLT3), known as the internal tandem duplication (ITD), were randomized to 24 months of maintenance therapy with either the FLT3 inhibitor gilteritinib or placebo.
The trial did not meet its primary endpoint, as there was no significant difference in relapse-free survival (RFS) between those assigned to the active drug and those given placebo, and there was no difference in overall survival rates.
However, subgroup analysis revealed that FLT3/ITD AML patients who were MRD+ after transplant, which represented approximately half of the participants, experienced a significant 48% improvement in RFS with gilteritinib versus placebo, while no benefit was seen in MRD– patients.
While acknowledging that the trial did not meet its primary endpoint, presenter Mark J. Levis, MD, PhD, program leader, hematologic malignancies and bone marrow transplant program, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Baltimore, said it was nevertheless “a successful study.”
“We learned how to use these drugs and in whom,” he continued, adding: “No, not everybody needs and should get a FLT3 inhibitor post-transplant, but we can use this [MRD] assay to identify who.”
Consequently, Dr. Levis believes that gilteritinib “should be a standard of care for those who are MRD positive,” although the decision to use it “should be balanced against the potential for toxicity,” compared with not adding an additional treatment after HCT.
He told a press conference that “we’re going to certainly make sure that patients who are MRD positive get [gilteritinib],” although the MRD negative patients “are going to be more questionable,” especially because the assay that they used in the study is not “perfect.”
Dr. Levis also suggested that the trial did not meet its endpoint because of regional differences in the clinical practice, such as in the number of treatment cycles prior to HCT, the time to transplant, and the previous use of a FLT3 inhibitor, all of which may have skewed the findings.
“Everybody in the world is convinced that they’re the best transplanter,” he said, and yet “they all do it differently, and the heterogeneity is astounding.”
He added: “If we’d restricted everybody [to a] pretransplant regimen, I suspect we would have had a different result than what we’re getting here, but this is releasing the drug into the world and saying: ‘Here, transplant however you want, however it’s practiced in the real world. Tell us how this works.’ ”
Approached for comment, Claudio Brunstein, MD, PhD, vice-chair of the department of hematology and oncology in the Cleveland Clinic Taussig Cancer Institute, said that while there was “some disappointment” with the results, he was “not surprised” that the trial did not meet its primary endpoint.
He said in an interview that the patient population was not of “high enough risk” to demonstrate an overall difference between gilteritinib and placebo, although he conceded that it is “hard to get to high-risk patients in a timely way” and so conduct a trial with them.
As to the notion that variations in clinical practice could have been responsible, Dr. Brunstein pointed out that it was a randomized trial, so the issue would have applied equally to both sides.
He nevertheless believes that it is “a very important study,” and “just the fact that it was done in the context of a number of drugs coming and being approved by the [U.S. Food and Drug Administration] in AML is quite remarkable.”
This is especially the case given that “many centers are already using [gilteritinib] as off-label maintenance therapy.”
Dr. Brunstein added that it is “good news” that the drug was effective in MRD+ patients, as it shows “you can overcome that with maintenance therapy rather than keeping giving more and more chemotherapy, especially as there are patients you’re worried about giving more intensive chemotherapy to make them MRD negative.”
He pointed out, however, that the assay used in the trial was “research grade” and very sensitive to MRD and “is not available everywhere, so there is an adjustment that the community will have to do to in order to apply this data.”
“But for those who are more obviously MRD positive with less sensitive assays, gilteritinib is already something that can be used,” Dr. Brunstein said.
Presenting the findings, Dr. Levis stated: “We all know that patients with FLT3/ITD AML have a high risk of relapse and are routinely referred for transplant. And we know that the detection of measurable residual disease pretransplant is highly predictive of outcome post-transplant.”
He continued that FLT3 inhibitors are “routinely given as post-transplant maintenance ... based on some prior trials, mostly with sorafenib.”
“But uncertainty exists as to the broad applicability of these trials,” Dr. Levis said. Moreover, the use of sorafenib in this context is “off label and can be difficult to tolerate,” and “we know that most patients are cured with allogeneic transplant alone.”
Gilteritinib is already known to be well tolerated as a monotherapy, and was approved by the FDA for the treatment of adult patients with FLT3 mutation–positive relapsed or refractory AML in 2018.
The investigators therefore examined whether it would be beneficial as a post-HCT maintenance therapy in FLT3-ITD AML. Patients were required to be in morphologic remission after one or two courses of induction therapy, with Dr. Levis underlining: “We did not allow patients who had been salvaged onto the study.”
They subsequently had a marrow aspirate sample taken for MRD analysis before undergoing allogeneic transplant, with any conditioning regimen, donor, or graft-versus-host disease (GVHD) prophylaxis allowed.
Between 30 and 90 days later, patients with successful engraftment who were able to take oral medication were then randomized to 24 months of maintenance therapy with either gilteritinib or placebo.
Dr. Levis showed that, among 620 patients screened at 110 centers in 16 countries, 356 were randomized between Aug. 15, 2017, and July 8, 2020. The median age was 53 years, and 49% of gilteritinib patients and 48% of those given placebo were female.
He noted that there was a “fairly even global distribution” of patients from North America, Europe, and the Asia/Pacific region, and that 60% of patients underwent a myeloablative conditioning regimen. Approximately the same proportion had received an FLT3 inhibitor prior to HCT.
MRD positivity, assessed at a cell count of ≥ 10-6, was observed pre-HCT in 47% of patients in both treatment groups, and in 50% of gilteritinib patients and 51% of placebo patients at both pre- and post-transplant assessments.
The treatment regimen was completed by 52.8% of patients assigned to gilteritinib and 53.9% in the placebo arm. Dr. Levis said that 18.5% and 20.3% of patients, respectively, experienced a grade 3/4 treatment emergent acute GVHD event, while 32.6% and 21.5%, respectively, had a grade ≥ 3 treatment emergent infection.
He noted that “adverse events were clearly more common in the gilteritinib arm and often led to either dose reduction or interruption, or withdrawal of treatment.”
The most common grade ≥ 3 treatment emergent adverse event was a decrease in neutrophil count, seen in 24.7% of gilteritinib patients and 7.9% of those given placebo, followed by reduced platelet count, in 15.2% and 5.6%, respectively, and anemia, in 6.2% and 1.7%, respectively.
Turning to the efficacy outcomes, Dr. Levis reported that the trial did not meet its primary endpoint, with no significant difference in RFS between the gilteritinib and placebo arms, at a hazard ratio of 0.679 (P = .0518). There was also no significant difference in the key secondary objective of overall survival, at a hazard ratio of 0.846 (P = .4394).
However, Dr. Levis noted that there was a “clear difference in the benefit of gilteritinib by region,” and, “at every level,” MRD predicted a benefit from gilteritinib, which he said was a “big surprise” and “really leapt out in the subgroup analysis.”
He explained that the researchers used a modified version of a two-step assay that has been used in previous studies, and was able to detect MRD at a sensitivity of approximately 1x10-6. “In our study, 98% of participants had samples pre- and post-[transplant].”
Regardless of treatment arm, MRD positivity measured at that sensitivity was associated with a significant reduction in overall survival, at a hazard ratio versus MRD– status of 0.514 (P = .0025).
When stratifying the patients by MRD status, the researchers found that, among MRD+ participants, gilteritinib was associated with a significant improvement in RFS, at a hazard ratio versus placebo of 0.515 (P = .0065), while there was no significant difference in MRD– patients.
Stratifying the patients by their conditioning regimen prior to HCT also revealed differences, with those undergoing myeloablative conditioning having significantly greater overall survival than those who underwent reduced-intensity conditioning, at a hazard ratio for death of 0.529 (P = .0027).
Dr. Levis said there is “no surprise there,” and the result could reflect the selection of fitter, younger patients to undergo the more intensive regimen.
He then showed that MRD+ patients who had undergone myeloablative conditioning had better overall survival with gilteritinib than placebo, at a hazard ratio for death of 0.418 (P = .0087). Again, the difference disappeared when looking at MRD– patients.
“So conditioning doesn’t help you in the setting of MRD,” Dr. Levis said.
Finally, he took a deeper dive into the regional differences in outcomes, noting that patients in the Asia/Pacific region, where gilteritinib showed no benefit over placebo, “were 10 years younger” than those in other regions, “tended to get myeloablative conditioning, and hardly ever used FLT3 inhibitors.”
In contrast, North American patients, who experienced a significant gilteritinib benefit in terms of RFS, underwent HCT an average of 26 days earlier than those elsewhere, and received fewer courses of chemotherapy pre-HCT. Moreover, 93.5% received an FLT3 inhibitor pretransplant.
The study was funded by Astellas Pharma Global Development. Dr. Levis declares relationships with Abbvie, Amgen, Astellas, Bristol-Myers-Squibb, Daiichi-Sankyo, GlaxoSmithKline, Jazz, Menarini, Pfizer, Sumitomo-Dainippon, Syndax, Takeda. Dr. Brunstein declares no relevant relationships.
AT EHA 2023
CMML: GM-CSF inhibitor lenzilumab shows early promise
There is currently no international standard of care for patients with CMML, but given its overlap with other myelodysplastic and myeloproliferative syndromes, CMML is usually treated with the hypomethylating agent azacitidine (Vidaza, Onureg), which is associated with objective response rates of 40%-50% and a complete response rate of less than 20%. Alternatively, some patients are treated with the antimetabolite hydroxurea in the palliative setting.
CMML is “insidious, it’s rare, but we think the incidence is increasing because more patients are now getting sequencing done by their doctors, and therapy [related] cases, patients that have survived chemo in the last 10 years, can also develop this disease,” said Daniel Thomas, MD, PhD, from the South Australian Health and Medical Research Institute, Adelaide, in an interview.
Dr. Thomas is a co-investigator of the ongoing phase 2/3 PREACH-M trial, which is testing a novel strategy of treating CMML with mutations in the RAS pathway with a combination of azacitidine and the investigational antibody lenzilumab, which is a targeted inhibitor of granulocyte-macrophage colony-stimulating factor (GM-CSF).
Preliminary results from the trial, reported at the European Hematology Association (EHA) annual meeting, showed that among 10 patients with CMML bearing mutations in the RAS pathway, the combination was associated with durable decreases in monocyte counts, increases in platelet counts and hemoglobin levels, and reductions in both spleen size and C-reactive protein level.
Targeting GM-CSF
More than 90% of cases of CMML carry somatic mutations that are thought to be leukemogenic, with an estimated 46%-60% of cases having mutations in TET2, a tumor suppressor, and an estimated 40% having mutations in KRAS, NRAS, or CBL, all of which are involved in cellular proliferation, and which, research suggests, are sensitive to GM-CSF inhibition.
“I was very surprised that the RAS-mutant arm – so, patients that have KRAS, NRAS, or CBL mutations – are just responding beautifully to [lenzilumab], ” Dr. Thomas said.
“It’s [in the] early days, but if what we’re seeing is durable across the next 10 patients, then I think we’re looking at a game changer,” he added.
Cameron Durrant, MD, DRCOG, MRCGP, chairman and CEO of lenzilumab’s maker Humanigen, said in an interview that the development of the antibody for CMML was spurred in part by research from investigators at the Mayo Clinic, showing that patients with mutations that increased sensitivity to GM-CSF seemed to have better clinical outcomes when the growth factor was blocked.
In addition, Dr. Durrant said, preclinical research from investigators at the Moffitt Cancer Center, Tampa, found that myeloid and monocytic progenitors “fed” on GM-CSF and were sensitive to GM-CSF signal inhibition.
“The biological idea that’s being explored here in the clinic in this study is that by blocking, or starving, if you will, those cells of that food, then you can prevent this overgrowth of certain blood cells that lead to chronic myelomonocytic leukemia,” he said.
PREACH-M details
Lenzilumab is an engineered human immunoglobulin G1-kappa monoclonal antibody with high affinity for human GM-CSF.
In the open label, nonrandomized PREACH-M trial, 72 patients with CMML were enrolled and were assigned to receive 24 monthly cycles of therapy depending on mutational status.
Patients with RAS pathway mutations were assigned to receive azacitidine delivered subcutaneously 75 mg/m2 for 7 days, plus intravenous lenzilumab 552 mg on days 1 and 15 of cycle 1 and on day 1 only of all subsequent cycles.
Patients with TET2 mutations only were assigned to receive azacitidine on the same schedule, plus IV sodium ascorbate 30 g for 7 days, with the first dose 15 g, and subsequent doses 30 g if there is no evidence of tumor lysis syndrome. Following IV administration, patients continue on oral sodium ascorbate 1.1 g on all other days.
The primary endpoint of complete and partial responses any time during the first 12 cycles is planned for reporting at the annual meeting of the American Society of Hematology in December, Dr. Thomas said.
At EHA 2023, the investigators reported available data on 10 patients enrolled in the lenzilumab arm and one enrolled in the azacitidine-sodium ascorbate arm.
Among patients in the lenzilumab arm there was a 5.1-fold decrease in monocyte counts (P = .03) and 2.4-fold decrease in blast counts (P = .04) at 12 months of follow-up.
In addition there was a trend toward increased platelet counts over baseline at 12 months, a significant increase in blood hemoglobin concentration (P = .024), a significant reduction in spleen size (P = .03) and a trend toward lower levels of the inflammatory marker C-reactive protein.
There were 21 grade 3 or 4 adverse events reported, of which 5 were deemed to be possibly related to lenzilumab.
Dr. Thomas told this news organization that the investigators have been “pleasantly surprised” at how well patients tolerated the monoclonal antibody.
“We haven’t had any infusion reactions, we haven’t had any pulmonary alveolar proteinosis, [and] we haven’t had any fevers from the infusion, from the antibody,” he said.
There were some instances of neutropenia and thrombocytopenia that the investigators think may have been related to azacitidine, he noted.
The study is sponsored by the National Health and Medical Research Council of Australia. Dr. Thomas reported no relevant financial relationships. Dr. Durrant is an employee and director of Humanigen.
A version of this article first appeared on Medscape.com.
There is currently no international standard of care for patients with CMML, but given its overlap with other myelodysplastic and myeloproliferative syndromes, CMML is usually treated with the hypomethylating agent azacitidine (Vidaza, Onureg), which is associated with objective response rates of 40%-50% and a complete response rate of less than 20%. Alternatively, some patients are treated with the antimetabolite hydroxurea in the palliative setting.
CMML is “insidious, it’s rare, but we think the incidence is increasing because more patients are now getting sequencing done by their doctors, and therapy [related] cases, patients that have survived chemo in the last 10 years, can also develop this disease,” said Daniel Thomas, MD, PhD, from the South Australian Health and Medical Research Institute, Adelaide, in an interview.
Dr. Thomas is a co-investigator of the ongoing phase 2/3 PREACH-M trial, which is testing a novel strategy of treating CMML with mutations in the RAS pathway with a combination of azacitidine and the investigational antibody lenzilumab, which is a targeted inhibitor of granulocyte-macrophage colony-stimulating factor (GM-CSF).
Preliminary results from the trial, reported at the European Hematology Association (EHA) annual meeting, showed that among 10 patients with CMML bearing mutations in the RAS pathway, the combination was associated with durable decreases in monocyte counts, increases in platelet counts and hemoglobin levels, and reductions in both spleen size and C-reactive protein level.
Targeting GM-CSF
More than 90% of cases of CMML carry somatic mutations that are thought to be leukemogenic, with an estimated 46%-60% of cases having mutations in TET2, a tumor suppressor, and an estimated 40% having mutations in KRAS, NRAS, or CBL, all of which are involved in cellular proliferation, and which, research suggests, are sensitive to GM-CSF inhibition.
“I was very surprised that the RAS-mutant arm – so, patients that have KRAS, NRAS, or CBL mutations – are just responding beautifully to [lenzilumab], ” Dr. Thomas said.
“It’s [in the] early days, but if what we’re seeing is durable across the next 10 patients, then I think we’re looking at a game changer,” he added.
Cameron Durrant, MD, DRCOG, MRCGP, chairman and CEO of lenzilumab’s maker Humanigen, said in an interview that the development of the antibody for CMML was spurred in part by research from investigators at the Mayo Clinic, showing that patients with mutations that increased sensitivity to GM-CSF seemed to have better clinical outcomes when the growth factor was blocked.
In addition, Dr. Durrant said, preclinical research from investigators at the Moffitt Cancer Center, Tampa, found that myeloid and monocytic progenitors “fed” on GM-CSF and were sensitive to GM-CSF signal inhibition.
“The biological idea that’s being explored here in the clinic in this study is that by blocking, or starving, if you will, those cells of that food, then you can prevent this overgrowth of certain blood cells that lead to chronic myelomonocytic leukemia,” he said.
PREACH-M details
Lenzilumab is an engineered human immunoglobulin G1-kappa monoclonal antibody with high affinity for human GM-CSF.
In the open label, nonrandomized PREACH-M trial, 72 patients with CMML were enrolled and were assigned to receive 24 monthly cycles of therapy depending on mutational status.
Patients with RAS pathway mutations were assigned to receive azacitidine delivered subcutaneously 75 mg/m2 for 7 days, plus intravenous lenzilumab 552 mg on days 1 and 15 of cycle 1 and on day 1 only of all subsequent cycles.
Patients with TET2 mutations only were assigned to receive azacitidine on the same schedule, plus IV sodium ascorbate 30 g for 7 days, with the first dose 15 g, and subsequent doses 30 g if there is no evidence of tumor lysis syndrome. Following IV administration, patients continue on oral sodium ascorbate 1.1 g on all other days.
The primary endpoint of complete and partial responses any time during the first 12 cycles is planned for reporting at the annual meeting of the American Society of Hematology in December, Dr. Thomas said.
At EHA 2023, the investigators reported available data on 10 patients enrolled in the lenzilumab arm and one enrolled in the azacitidine-sodium ascorbate arm.
Among patients in the lenzilumab arm there was a 5.1-fold decrease in monocyte counts (P = .03) and 2.4-fold decrease in blast counts (P = .04) at 12 months of follow-up.
In addition there was a trend toward increased platelet counts over baseline at 12 months, a significant increase in blood hemoglobin concentration (P = .024), a significant reduction in spleen size (P = .03) and a trend toward lower levels of the inflammatory marker C-reactive protein.
There were 21 grade 3 or 4 adverse events reported, of which 5 were deemed to be possibly related to lenzilumab.
Dr. Thomas told this news organization that the investigators have been “pleasantly surprised” at how well patients tolerated the monoclonal antibody.
“We haven’t had any infusion reactions, we haven’t had any pulmonary alveolar proteinosis, [and] we haven’t had any fevers from the infusion, from the antibody,” he said.
There were some instances of neutropenia and thrombocytopenia that the investigators think may have been related to azacitidine, he noted.
The study is sponsored by the National Health and Medical Research Council of Australia. Dr. Thomas reported no relevant financial relationships. Dr. Durrant is an employee and director of Humanigen.
A version of this article first appeared on Medscape.com.
There is currently no international standard of care for patients with CMML, but given its overlap with other myelodysplastic and myeloproliferative syndromes, CMML is usually treated with the hypomethylating agent azacitidine (Vidaza, Onureg), which is associated with objective response rates of 40%-50% and a complete response rate of less than 20%. Alternatively, some patients are treated with the antimetabolite hydroxurea in the palliative setting.
CMML is “insidious, it’s rare, but we think the incidence is increasing because more patients are now getting sequencing done by their doctors, and therapy [related] cases, patients that have survived chemo in the last 10 years, can also develop this disease,” said Daniel Thomas, MD, PhD, from the South Australian Health and Medical Research Institute, Adelaide, in an interview.
Dr. Thomas is a co-investigator of the ongoing phase 2/3 PREACH-M trial, which is testing a novel strategy of treating CMML with mutations in the RAS pathway with a combination of azacitidine and the investigational antibody lenzilumab, which is a targeted inhibitor of granulocyte-macrophage colony-stimulating factor (GM-CSF).
Preliminary results from the trial, reported at the European Hematology Association (EHA) annual meeting, showed that among 10 patients with CMML bearing mutations in the RAS pathway, the combination was associated with durable decreases in monocyte counts, increases in platelet counts and hemoglobin levels, and reductions in both spleen size and C-reactive protein level.
Targeting GM-CSF
More than 90% of cases of CMML carry somatic mutations that are thought to be leukemogenic, with an estimated 46%-60% of cases having mutations in TET2, a tumor suppressor, and an estimated 40% having mutations in KRAS, NRAS, or CBL, all of which are involved in cellular proliferation, and which, research suggests, are sensitive to GM-CSF inhibition.
“I was very surprised that the RAS-mutant arm – so, patients that have KRAS, NRAS, or CBL mutations – are just responding beautifully to [lenzilumab], ” Dr. Thomas said.
“It’s [in the] early days, but if what we’re seeing is durable across the next 10 patients, then I think we’re looking at a game changer,” he added.
Cameron Durrant, MD, DRCOG, MRCGP, chairman and CEO of lenzilumab’s maker Humanigen, said in an interview that the development of the antibody for CMML was spurred in part by research from investigators at the Mayo Clinic, showing that patients with mutations that increased sensitivity to GM-CSF seemed to have better clinical outcomes when the growth factor was blocked.
In addition, Dr. Durrant said, preclinical research from investigators at the Moffitt Cancer Center, Tampa, found that myeloid and monocytic progenitors “fed” on GM-CSF and were sensitive to GM-CSF signal inhibition.
“The biological idea that’s being explored here in the clinic in this study is that by blocking, or starving, if you will, those cells of that food, then you can prevent this overgrowth of certain blood cells that lead to chronic myelomonocytic leukemia,” he said.
PREACH-M details
Lenzilumab is an engineered human immunoglobulin G1-kappa monoclonal antibody with high affinity for human GM-CSF.
In the open label, nonrandomized PREACH-M trial, 72 patients with CMML were enrolled and were assigned to receive 24 monthly cycles of therapy depending on mutational status.
Patients with RAS pathway mutations were assigned to receive azacitidine delivered subcutaneously 75 mg/m2 for 7 days, plus intravenous lenzilumab 552 mg on days 1 and 15 of cycle 1 and on day 1 only of all subsequent cycles.
Patients with TET2 mutations only were assigned to receive azacitidine on the same schedule, plus IV sodium ascorbate 30 g for 7 days, with the first dose 15 g, and subsequent doses 30 g if there is no evidence of tumor lysis syndrome. Following IV administration, patients continue on oral sodium ascorbate 1.1 g on all other days.
The primary endpoint of complete and partial responses any time during the first 12 cycles is planned for reporting at the annual meeting of the American Society of Hematology in December, Dr. Thomas said.
At EHA 2023, the investigators reported available data on 10 patients enrolled in the lenzilumab arm and one enrolled in the azacitidine-sodium ascorbate arm.
Among patients in the lenzilumab arm there was a 5.1-fold decrease in monocyte counts (P = .03) and 2.4-fold decrease in blast counts (P = .04) at 12 months of follow-up.
In addition there was a trend toward increased platelet counts over baseline at 12 months, a significant increase in blood hemoglobin concentration (P = .024), a significant reduction in spleen size (P = .03) and a trend toward lower levels of the inflammatory marker C-reactive protein.
There were 21 grade 3 or 4 adverse events reported, of which 5 were deemed to be possibly related to lenzilumab.
Dr. Thomas told this news organization that the investigators have been “pleasantly surprised” at how well patients tolerated the monoclonal antibody.
“We haven’t had any infusion reactions, we haven’t had any pulmonary alveolar proteinosis, [and] we haven’t had any fevers from the infusion, from the antibody,” he said.
There were some instances of neutropenia and thrombocytopenia that the investigators think may have been related to azacitidine, he noted.
The study is sponsored by the National Health and Medical Research Council of Australia. Dr. Thomas reported no relevant financial relationships. Dr. Durrant is an employee and director of Humanigen.
A version of this article first appeared on Medscape.com.
FROM EHA 2023
PV: Novel rusfertide shows ‘impressive’ efficacy
“The results are surprisingly positive,” said senior author Ronald Hoffman, MD, of the Icahn School of Medicine at Mount Sinai, New York, in discussing the late-breaking research at a press briefing during the European Hematology Association Hybrid Congress 2023.
“Importantly, the study met all of its efficacy endpoints, including the proportion of responders, absence of phlebotomy eligibility, and hematocrit control,” Dr. Hoffman said.
PV, a relatively common clonal myeloproliferative neoplasm, is characterized by uncontrolled erythrocytosis, or excessive production of red blood cells, increasing the risk for serious complications such as thromboembolic and cardiovascular events – the most common causes of morbidity and mortality in this blood cancer.
To treat PV, the maintenance of hematocrit levels at below 45% is critical. However, the current standard of care, therapeutic phlebotomy, with or without cytoreductive agents, falls short in maintaining those lower levels in the majority of patients, Dr. Hoffman explained.
To improve responses, rusfertide was developed as a novel, synthetic form of hepcidin, a peptide hormone that is produced by the liver and functions to maintain iron homeostasis and control the formation of red blood cells.
“This is somewhat of a paradigm shift,” said Dr. Hoffman in the press briefing. “We’re trying to use a hormone made by the liver to control excessive red blood cell production from polycythemia vera.”
For the phase 2 REVIVE study evaluating rusfertide in PV, the authors enrolled 53 patients with PV who had a high phlebotomy burden while receiving the current standard of care. The study’s criteria called for patients to have received at least three therapeutic phlebotomies in the 28 weeks prior to enrollment, with or without concurrent cytoreductive agents.
During a first part of the study, patients received subcutaneous rusfertide once weekly over 28 weeks, during which period the dose was adjusted individually to achieve control of HCT levels below 45%.
The second part was a withdrawal phase extending from weeks 29 to 41, in which patients were randomized in a blinded fashion to either continue on rusfertide (n = 26) or receive a placebo (n = 27).
The patients had a median age of 58; they were 71.7% male, and 54.7% had previously been treated with therapeutic phlebotomy alone while 45.3% received therapeutic phlebotomy plus cytoreductive agents.
Patients were considered to be responders if they met three criteria, including having HCT control without phlebotomy eligibility, no therapeutic phlebotomy, and having completed 12 weeks of treatment.
At the end of the second phase, 69.2% of patients receiving rusfertide were responders versus just 18.5% in the placebo group (P = .0003).
Notably, the improvement with rusfertide was observed among those receiving therapeutic phlebotomy alone, as well as with cytoreductive agents (both P = .02).
Compared with placebo, rusfertide provided significant improvement in measures including the maintenance of response, the absence of the need for therapeutic phlebotomy, and persistent HCT control (P < .0001 for all).
Whereas the phlebotomy-free rate with rusfertide during the dose-finding weeks of 1-17 was 76.9% and in weeks 17-29, 87.3%, the rate increased in part 2 of the study to 92.3%.
Additional symptom benefits reported with rusfertide at week 29 versus baseline in part 1 of the study included significant improvements in concentration (P = .0018), itching (P = .0054), fatigue (P = .0074), and inactivity (P = .0005).
In terms of safety, rusfertide was generally well tolerated, with 83% of treatment-emergent adverse events (TEAEs) being grade 1-2, while 17% were grade 3, and none were grade 4 or 5.
The most common TEAEs consisted of injection-site reactions, which were localized, and grade 1-2 in severity. The incidence of reactions decreased with ongoing treatment. There were only two discontinuations resulting from TEAEs.
Among a total of 70 patients who were enrolled, 52 (74.3%) have continued to receive rusfertide for at least 1 year, 32 (45.7%) for at least 1.5 years, and 10 (14.3%) for at least 2 years, indicating the long-term tolerability of rusfertide.
Further commenting, first author Marina Kremyanskaya, MD, PhD, an assistant professor of medicine, hematology, and medical oncology at the Icahn School of Medicine at Mount Sinai, added that a key benefit is rusfertide’s tolerability with combination therapies, which is important in enabling the avoidance of phlebotomies.
“Many patients on cytoreductive therapies still require phlebotomies, and they can’t tolerate a dose increase, either due to cytopenias or other adverse reactions,” she said in an interview. “So adding rusfertide allows for better control of their hematocrits on a lower dose of their respective cytoreductive drug.”
“The combination treatment thus allows for elimination of phlebotomy requirements and potentially improves their symptoms,” Dr. Kremyanskaya said, adding that “using a lower dose of cytoreductive drug such as interferon or hydroxyurea could offer a symptomatic relief to patients as well.”
Overall, she agreed that the responses are remarkably positive.
“I think this is what is so impressive about this agent – basically everybody responds,” Dr. Kremyanskaya said. “When we first started treating patients, we were so impressed, as none of the other drugs we use to treat PV, or any other hematologic malignancy, come anywhere close to this response rate.”
In commenting on the study, Claire Harrison, MD, a professor of myeloproliferative neoplasms and deputy medical director of research at Guy’s and St Thomas’ NHS Foundation Trust in London, agreed that “these data show a strong signal for effectiveness of this therapy in controlling red cell proliferation in PV without inducing iron deficiency and adding to the symptom burden of patients.”
The alternative of phlebotomy “is painful and consumes patient time and hospital resources,” she said in an interview.
Dr. Harrison noted that an earlier signal suggested squamous cell cancer might be of potential concern, but the signal “has not re-emerged [suggesting] this does indeed seem to be a safe and extremely effective therapy.”
Further commenting on the study during the press briefing, Konstanze Döhner, MD, of the University of Ulm (Germany) added that “this is exciting data.”
“For a long time, we had no therapeutic options for PV, and now the field is rapidly developing,” she said.
In ongoing research, rusfertide is currently being studied in the phase 3, placebo-controlled VERIFY randomized trial.
The study was sponsored by Protagonist Therapeutics. Dr. Hoffman reports being on the advisory board for Protagonist Therapeutics, and Dr. Kremyanskaya is a consultant for Protagonist Therapeutics. Dr. Harrison had no disclosures to report.
“The results are surprisingly positive,” said senior author Ronald Hoffman, MD, of the Icahn School of Medicine at Mount Sinai, New York, in discussing the late-breaking research at a press briefing during the European Hematology Association Hybrid Congress 2023.
“Importantly, the study met all of its efficacy endpoints, including the proportion of responders, absence of phlebotomy eligibility, and hematocrit control,” Dr. Hoffman said.
PV, a relatively common clonal myeloproliferative neoplasm, is characterized by uncontrolled erythrocytosis, or excessive production of red blood cells, increasing the risk for serious complications such as thromboembolic and cardiovascular events – the most common causes of morbidity and mortality in this blood cancer.
To treat PV, the maintenance of hematocrit levels at below 45% is critical. However, the current standard of care, therapeutic phlebotomy, with or without cytoreductive agents, falls short in maintaining those lower levels in the majority of patients, Dr. Hoffman explained.
To improve responses, rusfertide was developed as a novel, synthetic form of hepcidin, a peptide hormone that is produced by the liver and functions to maintain iron homeostasis and control the formation of red blood cells.
“This is somewhat of a paradigm shift,” said Dr. Hoffman in the press briefing. “We’re trying to use a hormone made by the liver to control excessive red blood cell production from polycythemia vera.”
For the phase 2 REVIVE study evaluating rusfertide in PV, the authors enrolled 53 patients with PV who had a high phlebotomy burden while receiving the current standard of care. The study’s criteria called for patients to have received at least three therapeutic phlebotomies in the 28 weeks prior to enrollment, with or without concurrent cytoreductive agents.
During a first part of the study, patients received subcutaneous rusfertide once weekly over 28 weeks, during which period the dose was adjusted individually to achieve control of HCT levels below 45%.
The second part was a withdrawal phase extending from weeks 29 to 41, in which patients were randomized in a blinded fashion to either continue on rusfertide (n = 26) or receive a placebo (n = 27).
The patients had a median age of 58; they were 71.7% male, and 54.7% had previously been treated with therapeutic phlebotomy alone while 45.3% received therapeutic phlebotomy plus cytoreductive agents.
Patients were considered to be responders if they met three criteria, including having HCT control without phlebotomy eligibility, no therapeutic phlebotomy, and having completed 12 weeks of treatment.
At the end of the second phase, 69.2% of patients receiving rusfertide were responders versus just 18.5% in the placebo group (P = .0003).
Notably, the improvement with rusfertide was observed among those receiving therapeutic phlebotomy alone, as well as with cytoreductive agents (both P = .02).
Compared with placebo, rusfertide provided significant improvement in measures including the maintenance of response, the absence of the need for therapeutic phlebotomy, and persistent HCT control (P < .0001 for all).
Whereas the phlebotomy-free rate with rusfertide during the dose-finding weeks of 1-17 was 76.9% and in weeks 17-29, 87.3%, the rate increased in part 2 of the study to 92.3%.
Additional symptom benefits reported with rusfertide at week 29 versus baseline in part 1 of the study included significant improvements in concentration (P = .0018), itching (P = .0054), fatigue (P = .0074), and inactivity (P = .0005).
In terms of safety, rusfertide was generally well tolerated, with 83% of treatment-emergent adverse events (TEAEs) being grade 1-2, while 17% were grade 3, and none were grade 4 or 5.
The most common TEAEs consisted of injection-site reactions, which were localized, and grade 1-2 in severity. The incidence of reactions decreased with ongoing treatment. There were only two discontinuations resulting from TEAEs.
Among a total of 70 patients who were enrolled, 52 (74.3%) have continued to receive rusfertide for at least 1 year, 32 (45.7%) for at least 1.5 years, and 10 (14.3%) for at least 2 years, indicating the long-term tolerability of rusfertide.
Further commenting, first author Marina Kremyanskaya, MD, PhD, an assistant professor of medicine, hematology, and medical oncology at the Icahn School of Medicine at Mount Sinai, added that a key benefit is rusfertide’s tolerability with combination therapies, which is important in enabling the avoidance of phlebotomies.
“Many patients on cytoreductive therapies still require phlebotomies, and they can’t tolerate a dose increase, either due to cytopenias or other adverse reactions,” she said in an interview. “So adding rusfertide allows for better control of their hematocrits on a lower dose of their respective cytoreductive drug.”
“The combination treatment thus allows for elimination of phlebotomy requirements and potentially improves their symptoms,” Dr. Kremyanskaya said, adding that “using a lower dose of cytoreductive drug such as interferon or hydroxyurea could offer a symptomatic relief to patients as well.”
Overall, she agreed that the responses are remarkably positive.
“I think this is what is so impressive about this agent – basically everybody responds,” Dr. Kremyanskaya said. “When we first started treating patients, we were so impressed, as none of the other drugs we use to treat PV, or any other hematologic malignancy, come anywhere close to this response rate.”
In commenting on the study, Claire Harrison, MD, a professor of myeloproliferative neoplasms and deputy medical director of research at Guy’s and St Thomas’ NHS Foundation Trust in London, agreed that “these data show a strong signal for effectiveness of this therapy in controlling red cell proliferation in PV without inducing iron deficiency and adding to the symptom burden of patients.”
The alternative of phlebotomy “is painful and consumes patient time and hospital resources,” she said in an interview.
Dr. Harrison noted that an earlier signal suggested squamous cell cancer might be of potential concern, but the signal “has not re-emerged [suggesting] this does indeed seem to be a safe and extremely effective therapy.”
Further commenting on the study during the press briefing, Konstanze Döhner, MD, of the University of Ulm (Germany) added that “this is exciting data.”
“For a long time, we had no therapeutic options for PV, and now the field is rapidly developing,” she said.
In ongoing research, rusfertide is currently being studied in the phase 3, placebo-controlled VERIFY randomized trial.
The study was sponsored by Protagonist Therapeutics. Dr. Hoffman reports being on the advisory board for Protagonist Therapeutics, and Dr. Kremyanskaya is a consultant for Protagonist Therapeutics. Dr. Harrison had no disclosures to report.
“The results are surprisingly positive,” said senior author Ronald Hoffman, MD, of the Icahn School of Medicine at Mount Sinai, New York, in discussing the late-breaking research at a press briefing during the European Hematology Association Hybrid Congress 2023.
“Importantly, the study met all of its efficacy endpoints, including the proportion of responders, absence of phlebotomy eligibility, and hematocrit control,” Dr. Hoffman said.
PV, a relatively common clonal myeloproliferative neoplasm, is characterized by uncontrolled erythrocytosis, or excessive production of red blood cells, increasing the risk for serious complications such as thromboembolic and cardiovascular events – the most common causes of morbidity and mortality in this blood cancer.
To treat PV, the maintenance of hematocrit levels at below 45% is critical. However, the current standard of care, therapeutic phlebotomy, with or without cytoreductive agents, falls short in maintaining those lower levels in the majority of patients, Dr. Hoffman explained.
To improve responses, rusfertide was developed as a novel, synthetic form of hepcidin, a peptide hormone that is produced by the liver and functions to maintain iron homeostasis and control the formation of red blood cells.
“This is somewhat of a paradigm shift,” said Dr. Hoffman in the press briefing. “We’re trying to use a hormone made by the liver to control excessive red blood cell production from polycythemia vera.”
For the phase 2 REVIVE study evaluating rusfertide in PV, the authors enrolled 53 patients with PV who had a high phlebotomy burden while receiving the current standard of care. The study’s criteria called for patients to have received at least three therapeutic phlebotomies in the 28 weeks prior to enrollment, with or without concurrent cytoreductive agents.
During a first part of the study, patients received subcutaneous rusfertide once weekly over 28 weeks, during which period the dose was adjusted individually to achieve control of HCT levels below 45%.
The second part was a withdrawal phase extending from weeks 29 to 41, in which patients were randomized in a blinded fashion to either continue on rusfertide (n = 26) or receive a placebo (n = 27).
The patients had a median age of 58; they were 71.7% male, and 54.7% had previously been treated with therapeutic phlebotomy alone while 45.3% received therapeutic phlebotomy plus cytoreductive agents.
Patients were considered to be responders if they met three criteria, including having HCT control without phlebotomy eligibility, no therapeutic phlebotomy, and having completed 12 weeks of treatment.
At the end of the second phase, 69.2% of patients receiving rusfertide were responders versus just 18.5% in the placebo group (P = .0003).
Notably, the improvement with rusfertide was observed among those receiving therapeutic phlebotomy alone, as well as with cytoreductive agents (both P = .02).
Compared with placebo, rusfertide provided significant improvement in measures including the maintenance of response, the absence of the need for therapeutic phlebotomy, and persistent HCT control (P < .0001 for all).
Whereas the phlebotomy-free rate with rusfertide during the dose-finding weeks of 1-17 was 76.9% and in weeks 17-29, 87.3%, the rate increased in part 2 of the study to 92.3%.
Additional symptom benefits reported with rusfertide at week 29 versus baseline in part 1 of the study included significant improvements in concentration (P = .0018), itching (P = .0054), fatigue (P = .0074), and inactivity (P = .0005).
In terms of safety, rusfertide was generally well tolerated, with 83% of treatment-emergent adverse events (TEAEs) being grade 1-2, while 17% were grade 3, and none were grade 4 or 5.
The most common TEAEs consisted of injection-site reactions, which were localized, and grade 1-2 in severity. The incidence of reactions decreased with ongoing treatment. There were only two discontinuations resulting from TEAEs.
Among a total of 70 patients who were enrolled, 52 (74.3%) have continued to receive rusfertide for at least 1 year, 32 (45.7%) for at least 1.5 years, and 10 (14.3%) for at least 2 years, indicating the long-term tolerability of rusfertide.
Further commenting, first author Marina Kremyanskaya, MD, PhD, an assistant professor of medicine, hematology, and medical oncology at the Icahn School of Medicine at Mount Sinai, added that a key benefit is rusfertide’s tolerability with combination therapies, which is important in enabling the avoidance of phlebotomies.
“Many patients on cytoreductive therapies still require phlebotomies, and they can’t tolerate a dose increase, either due to cytopenias or other adverse reactions,” she said in an interview. “So adding rusfertide allows for better control of their hematocrits on a lower dose of their respective cytoreductive drug.”
“The combination treatment thus allows for elimination of phlebotomy requirements and potentially improves their symptoms,” Dr. Kremyanskaya said, adding that “using a lower dose of cytoreductive drug such as interferon or hydroxyurea could offer a symptomatic relief to patients as well.”
Overall, she agreed that the responses are remarkably positive.
“I think this is what is so impressive about this agent – basically everybody responds,” Dr. Kremyanskaya said. “When we first started treating patients, we were so impressed, as none of the other drugs we use to treat PV, or any other hematologic malignancy, come anywhere close to this response rate.”
In commenting on the study, Claire Harrison, MD, a professor of myeloproliferative neoplasms and deputy medical director of research at Guy’s and St Thomas’ NHS Foundation Trust in London, agreed that “these data show a strong signal for effectiveness of this therapy in controlling red cell proliferation in PV without inducing iron deficiency and adding to the symptom burden of patients.”
The alternative of phlebotomy “is painful and consumes patient time and hospital resources,” she said in an interview.
Dr. Harrison noted that an earlier signal suggested squamous cell cancer might be of potential concern, but the signal “has not re-emerged [suggesting] this does indeed seem to be a safe and extremely effective therapy.”
Further commenting on the study during the press briefing, Konstanze Döhner, MD, of the University of Ulm (Germany) added that “this is exciting data.”
“For a long time, we had no therapeutic options for PV, and now the field is rapidly developing,” she said.
In ongoing research, rusfertide is currently being studied in the phase 3, placebo-controlled VERIFY randomized trial.
The study was sponsored by Protagonist Therapeutics. Dr. Hoffman reports being on the advisory board for Protagonist Therapeutics, and Dr. Kremyanskaya is a consultant for Protagonist Therapeutics. Dr. Harrison had no disclosures to report.
FROM EHA 2023
CLL: Venetoclax-obinutuzumab combo effective long term
Initial results from the trial were shown at the EHA 2019 annual meeting and reported at the time by this news organization.
They revealed that, among more than 430 CLL patients with a median age of over 70 years and multiple comorbidities, the combination of venetoclax, a B-cell lymphoma 2 protein blocker, plus obinutuzumab, an anti-CD20 monoclonal antibody, was associated with a 65% improvement in PFS, compared with chlorambucil, a chemotherapy agent, plus obinutuzumab.
On the strength of these findings, the venetoclax-obinutuzumab combination received Food and Drug Administration approval for previously untreated CLL and small lymphocytic lymphoma in March 2019.
The latest analysis, presented by Othman Al-Sawaf, MD, University Hospital of Cologne (Germany), showed that despite having just 12 cycles of treatment, patients treated with venetoclax-obinutuzumab continued to experience a significant PFS benefit over those given the chemotherapy-based regimen, including in high-risk patients, after more than 6 years of follow-up.
Dr. Al-Sawaf noted that more than 50% of patients given the experimental combination remained without a PFS event at the latest follow-up, and that over 60% had not required a second treatment, equating to a 66% reduction in the likelihood of needing a second treatment versus chlorambucil-obinutuzumab.
Dr. Al-Sawaf said at a press conference that, “clinically, the standard of care for any CLL if it is asymptomatic” is watch and wait, which is “true in the frontline setting, but also in the relapse setting.”
Therefore, these patients “do not need to initiate the next line of treatment, and that’s why time to next treatment is so interesting.”
He added that there also were no new safety signals, with adverse event rates dropping markedly once treatment was over, although there was a suggestion of an increase in second malignancies with venetoclax-obinutuzumab.
“We’ve seen, in many studies now that use fixed-duration approaches, that there is virtually no posttreatment toxicity once patients are able to get off treatment,” Dr. Al-Sawaf said, adding: “This really highlights the benefit” of stopping treatment, “which is a clear advantage compared to having any kind of continuous treatment.”
Approached for comment, William G. Wierda, MD, PhD, professor, department of leukemia, division of cancer medicine, University of Texas MD Anderson Cancer Center, Houston, emphasized the value of the 6-year follow-up of the study, adding that these are “very impressive data.”
He told this news organization that, in terms of the ongoing PFS improvement, “we wouldn’t expect anything otherwise” with venetoclax-obinutuzumab when compared with the chemotherapy-based regimen, but that the trend for an improvement in overall survival is of particular interest.
This “is a notable feature of the update,” Dr. Wierda said, and “we will continue to watch the long-term overall survival curves with a longer follow-up,” especially as the separation of the curves between the two regimens is “more prominent” than in previous analyses of CLL14.
He also pointed to the low incidence of grade ≥ 3 adverse events in patients who are in remission, which “support the use of fixed-duration chemo-free” treatments, and the longer follow-up now allowing the contribution of high-risk features to outcomes to be teased out in multivariate analysis.
“The data that we’re looking for in the next update of this is some indication about improved outcomes between patients with a mutated and unmutated immunoglobulin heavy chain gene [IgHV], in regard to undetectable MRD [minimal residual disease] status,” Dr. Wierda said.
“We know that mutational status correlates with progression free survival,” he explained. “What we would like to see moving forward is how that is associated with undetectable MRD status at the end of treatment.”
Dr. Wierda said that the next hotly anticipated trial in the field is CLL17, which is comparing ibrutinib monotherapy to fixed-duration venetoclax-obinutuzumab to fixed-duration ibrutinib-venetoclax in patients with previously untreated CLL.
“That’s the next question: Is there any advantage of a BTK [Bruton’s tyrosine kinase] inhibitor with venetoclax over venetoclax plus the CD20 antibody?”
Dr. Al-Sawaf, in presenting the latest analysis, reminded the audience that CLL14 was a randomized phase 3 study focusing on patients with previously untreated CLL and coexisting conditions who were randomized to either venetoclax-obinutuzumab for six cycles, followed by six cycles of venetoclax, or chlorambucil-obinutuzumab for six cycles, followed by chlorambucil for six cycles.
The patients, who were enrolled between 2015 and 2016, were required to have a Cumulative Illness Rating Scale (CIRS) score > 6 and/or creatinine clearance < 70 mL/min, which Dr. Al-Sawaf explained serves as “indicator of the unfitness of the patients.”
A total of 432 patients took part in the study. The median age across the two treatment groups was 71-72 years, and the median total CIRS score was 8-9. The majority of patients (79%-80%) had Binet stage B or C CLL. An intermediate tumor lysis syndrome risk was identified in 64%-68%.
“We also had a fair share of patients with high-risk disease,” Dr. Al-Sawaf noted, with approximately 60% having an unmutated IGHV status, and 12% having a TP53 mutation, both of which are associated with a poorer prognosis.
He added that the “aim of these long-term observations that we try to do every year is not so much to do the comparisons to chlorambucil-obinutuzumab, which we appreciate is not necessarily a standard of care anymore,” but rather to understand the safety and effectiveness of venetoclax-obinutuzumab “in the long run, given that all patients are off treatment.”
Beginning with the safety data, Dr. Al-Sawaf showed that rates of grade ≥ 3 adverse events plummeted after the treatment period, with rates of neutropenia falling from 51.9% with venetoclax-obinutuzumab and 47.2% with chlorambucil-obinutuzumab during treatment to 3.8% and 1.9%, respectively, post treatment.
Similarly, rates of thrombocytopenia decreased from 14.2% on treatment to 0.5% off treatment in patients given venetoclax-obinutuzumab, and from 15.0% to 0.0% in the chlorambucil-obinutuzumab group.
One note of caution was sounded over the proportion of patients with at least one second primary malignancy following treatment, which was numerically higher with venetoclax-obinutuzumab, at 14.2% versus 8.4% with the chemotherapy-based regimen.
“But this is a rather a heterogeneous pattern of solid organ tumors and melanoma,” Dr. Al-Sawaf said, referring to the additional malignancies in the venetoclax-obinutuzumab arm. These included lung cancer, prostate cancer and breast cancer.
He said, however, there was no “specific pattern that we can really pinpoint ... and, importantly, the difference is not statistically significant.”
Turning to the efficacy outcomes, Dr. Al-Sawaf showed that, after median follow-up of 76.4 months, the separation in PFS between the two treatment arms continued, with the median PFS 76.2 months with venetoclax-obinutuzumab versus 36.4 months with chlorambucil-obinutuzumab, at a hazard ratio 0.40 (P < .0001).
The 6-year PFS rate in patients treated with venetoclax-obinutuzumab was 53.1% versus 21.7% with the chemotherapy-based regimen. Looking at the high-risk groups, Dr. Al-Sawaf reported that there was a similar pattern of benefit with venetoclax-obinutuzumab.
Among patients with a TP53 mutation, the median PFS was 51.9 months with the combination versus 20.8 months in those given chlorambucil-obinutuzumab, while the corresponding durations in patients with unmutated IGHV were 64.8 months and 26.9 months, respectively.
Multivariate analysis demonstrated that IGHV status was an independent predictor of PFS in patients treated with venetoclax-obinutuzumab, as was the presence of a TP53 mutation, and lymph node size ≥ 5 cm.
There was no significant difference in overall survival between the two treatment groups, although there was a numerical difference in 6-year overall survival rates, at 78.7% with the experimental combination versus 69.2% with chlorambucil-obinutuzumab.
Patients with a minimal residual disease (MRD) count ≥ 10-4 had a shorter overall survival than did those with MRD < 10-4.
“We are currently working up to understand which group of patients experiences these tremendous long term remissions,” Dr. Al-Sawaf said, “and we will keep you posted on this.”
He also showed that the time to next treatment (TTNT), defined as time to death or next anti-leukemic treatment, was significantly longer with venetoclax-obinutuzumab, with the median not reached before the current data lock versus 52.9 months with the chemotherapy-based regimen.
This equated to a hazard ratio in favor of the experimental combination of 0.44 (P < .0001), and a 6-year TTNT rate of 65.2% versus 37.1% for chlorambucil-obinutuzumab.
That second treatment was a Bruton’s tyrosine kinase inhibitor in 59.0% of cases in the venetoclax-obinutuzumab arm and 53.4% in the chlorambucil-obinutuzumab group.
Dr. Al-Sawaf noted, however, that 23.1% and 30.1%, respectively, of patients were given a chemotherapy or chemo-immunotherapy regimen, “which we nowadays would not necessarily consider a standard of care.”
“This ultimately reflects, as in many global clinical studies, the disparities that we still have across the world in terms of access to state-of-the-art therapies.”
The study was sponsored by Hoffmann–La Roche, and conducted in collaboration with AbbVie, and the German CLL Study Group. Dr. Al-Sawaf disclosed relationships with AbbVie, Adaptive, Ascentage, AstraZeneca, BeiGene, Gilead, Janssen, Lilly, and Roche.
Initial results from the trial were shown at the EHA 2019 annual meeting and reported at the time by this news organization.
They revealed that, among more than 430 CLL patients with a median age of over 70 years and multiple comorbidities, the combination of venetoclax, a B-cell lymphoma 2 protein blocker, plus obinutuzumab, an anti-CD20 monoclonal antibody, was associated with a 65% improvement in PFS, compared with chlorambucil, a chemotherapy agent, plus obinutuzumab.
On the strength of these findings, the venetoclax-obinutuzumab combination received Food and Drug Administration approval for previously untreated CLL and small lymphocytic lymphoma in March 2019.
The latest analysis, presented by Othman Al-Sawaf, MD, University Hospital of Cologne (Germany), showed that despite having just 12 cycles of treatment, patients treated with venetoclax-obinutuzumab continued to experience a significant PFS benefit over those given the chemotherapy-based regimen, including in high-risk patients, after more than 6 years of follow-up.
Dr. Al-Sawaf noted that more than 50% of patients given the experimental combination remained without a PFS event at the latest follow-up, and that over 60% had not required a second treatment, equating to a 66% reduction in the likelihood of needing a second treatment versus chlorambucil-obinutuzumab.
Dr. Al-Sawaf said at a press conference that, “clinically, the standard of care for any CLL if it is asymptomatic” is watch and wait, which is “true in the frontline setting, but also in the relapse setting.”
Therefore, these patients “do not need to initiate the next line of treatment, and that’s why time to next treatment is so interesting.”
He added that there also were no new safety signals, with adverse event rates dropping markedly once treatment was over, although there was a suggestion of an increase in second malignancies with venetoclax-obinutuzumab.
“We’ve seen, in many studies now that use fixed-duration approaches, that there is virtually no posttreatment toxicity once patients are able to get off treatment,” Dr. Al-Sawaf said, adding: “This really highlights the benefit” of stopping treatment, “which is a clear advantage compared to having any kind of continuous treatment.”
Approached for comment, William G. Wierda, MD, PhD, professor, department of leukemia, division of cancer medicine, University of Texas MD Anderson Cancer Center, Houston, emphasized the value of the 6-year follow-up of the study, adding that these are “very impressive data.”
He told this news organization that, in terms of the ongoing PFS improvement, “we wouldn’t expect anything otherwise” with venetoclax-obinutuzumab when compared with the chemotherapy-based regimen, but that the trend for an improvement in overall survival is of particular interest.
This “is a notable feature of the update,” Dr. Wierda said, and “we will continue to watch the long-term overall survival curves with a longer follow-up,” especially as the separation of the curves between the two regimens is “more prominent” than in previous analyses of CLL14.
He also pointed to the low incidence of grade ≥ 3 adverse events in patients who are in remission, which “support the use of fixed-duration chemo-free” treatments, and the longer follow-up now allowing the contribution of high-risk features to outcomes to be teased out in multivariate analysis.
“The data that we’re looking for in the next update of this is some indication about improved outcomes between patients with a mutated and unmutated immunoglobulin heavy chain gene [IgHV], in regard to undetectable MRD [minimal residual disease] status,” Dr. Wierda said.
“We know that mutational status correlates with progression free survival,” he explained. “What we would like to see moving forward is how that is associated with undetectable MRD status at the end of treatment.”
Dr. Wierda said that the next hotly anticipated trial in the field is CLL17, which is comparing ibrutinib monotherapy to fixed-duration venetoclax-obinutuzumab to fixed-duration ibrutinib-venetoclax in patients with previously untreated CLL.
“That’s the next question: Is there any advantage of a BTK [Bruton’s tyrosine kinase] inhibitor with venetoclax over venetoclax plus the CD20 antibody?”
Dr. Al-Sawaf, in presenting the latest analysis, reminded the audience that CLL14 was a randomized phase 3 study focusing on patients with previously untreated CLL and coexisting conditions who were randomized to either venetoclax-obinutuzumab for six cycles, followed by six cycles of venetoclax, or chlorambucil-obinutuzumab for six cycles, followed by chlorambucil for six cycles.
The patients, who were enrolled between 2015 and 2016, were required to have a Cumulative Illness Rating Scale (CIRS) score > 6 and/or creatinine clearance < 70 mL/min, which Dr. Al-Sawaf explained serves as “indicator of the unfitness of the patients.”
A total of 432 patients took part in the study. The median age across the two treatment groups was 71-72 years, and the median total CIRS score was 8-9. The majority of patients (79%-80%) had Binet stage B or C CLL. An intermediate tumor lysis syndrome risk was identified in 64%-68%.
“We also had a fair share of patients with high-risk disease,” Dr. Al-Sawaf noted, with approximately 60% having an unmutated IGHV status, and 12% having a TP53 mutation, both of which are associated with a poorer prognosis.
He added that the “aim of these long-term observations that we try to do every year is not so much to do the comparisons to chlorambucil-obinutuzumab, which we appreciate is not necessarily a standard of care anymore,” but rather to understand the safety and effectiveness of venetoclax-obinutuzumab “in the long run, given that all patients are off treatment.”
Beginning with the safety data, Dr. Al-Sawaf showed that rates of grade ≥ 3 adverse events plummeted after the treatment period, with rates of neutropenia falling from 51.9% with venetoclax-obinutuzumab and 47.2% with chlorambucil-obinutuzumab during treatment to 3.8% and 1.9%, respectively, post treatment.
Similarly, rates of thrombocytopenia decreased from 14.2% on treatment to 0.5% off treatment in patients given venetoclax-obinutuzumab, and from 15.0% to 0.0% in the chlorambucil-obinutuzumab group.
One note of caution was sounded over the proportion of patients with at least one second primary malignancy following treatment, which was numerically higher with venetoclax-obinutuzumab, at 14.2% versus 8.4% with the chemotherapy-based regimen.
“But this is a rather a heterogeneous pattern of solid organ tumors and melanoma,” Dr. Al-Sawaf said, referring to the additional malignancies in the venetoclax-obinutuzumab arm. These included lung cancer, prostate cancer and breast cancer.
He said, however, there was no “specific pattern that we can really pinpoint ... and, importantly, the difference is not statistically significant.”
Turning to the efficacy outcomes, Dr. Al-Sawaf showed that, after median follow-up of 76.4 months, the separation in PFS between the two treatment arms continued, with the median PFS 76.2 months with venetoclax-obinutuzumab versus 36.4 months with chlorambucil-obinutuzumab, at a hazard ratio 0.40 (P < .0001).
The 6-year PFS rate in patients treated with venetoclax-obinutuzumab was 53.1% versus 21.7% with the chemotherapy-based regimen. Looking at the high-risk groups, Dr. Al-Sawaf reported that there was a similar pattern of benefit with venetoclax-obinutuzumab.
Among patients with a TP53 mutation, the median PFS was 51.9 months with the combination versus 20.8 months in those given chlorambucil-obinutuzumab, while the corresponding durations in patients with unmutated IGHV were 64.8 months and 26.9 months, respectively.
Multivariate analysis demonstrated that IGHV status was an independent predictor of PFS in patients treated with venetoclax-obinutuzumab, as was the presence of a TP53 mutation, and lymph node size ≥ 5 cm.
There was no significant difference in overall survival between the two treatment groups, although there was a numerical difference in 6-year overall survival rates, at 78.7% with the experimental combination versus 69.2% with chlorambucil-obinutuzumab.
Patients with a minimal residual disease (MRD) count ≥ 10-4 had a shorter overall survival than did those with MRD < 10-4.
“We are currently working up to understand which group of patients experiences these tremendous long term remissions,” Dr. Al-Sawaf said, “and we will keep you posted on this.”
He also showed that the time to next treatment (TTNT), defined as time to death or next anti-leukemic treatment, was significantly longer with venetoclax-obinutuzumab, with the median not reached before the current data lock versus 52.9 months with the chemotherapy-based regimen.
This equated to a hazard ratio in favor of the experimental combination of 0.44 (P < .0001), and a 6-year TTNT rate of 65.2% versus 37.1% for chlorambucil-obinutuzumab.
That second treatment was a Bruton’s tyrosine kinase inhibitor in 59.0% of cases in the venetoclax-obinutuzumab arm and 53.4% in the chlorambucil-obinutuzumab group.
Dr. Al-Sawaf noted, however, that 23.1% and 30.1%, respectively, of patients were given a chemotherapy or chemo-immunotherapy regimen, “which we nowadays would not necessarily consider a standard of care.”
“This ultimately reflects, as in many global clinical studies, the disparities that we still have across the world in terms of access to state-of-the-art therapies.”
The study was sponsored by Hoffmann–La Roche, and conducted in collaboration with AbbVie, and the German CLL Study Group. Dr. Al-Sawaf disclosed relationships with AbbVie, Adaptive, Ascentage, AstraZeneca, BeiGene, Gilead, Janssen, Lilly, and Roche.
Initial results from the trial were shown at the EHA 2019 annual meeting and reported at the time by this news organization.
They revealed that, among more than 430 CLL patients with a median age of over 70 years and multiple comorbidities, the combination of venetoclax, a B-cell lymphoma 2 protein blocker, plus obinutuzumab, an anti-CD20 monoclonal antibody, was associated with a 65% improvement in PFS, compared with chlorambucil, a chemotherapy agent, plus obinutuzumab.
On the strength of these findings, the venetoclax-obinutuzumab combination received Food and Drug Administration approval for previously untreated CLL and small lymphocytic lymphoma in March 2019.
The latest analysis, presented by Othman Al-Sawaf, MD, University Hospital of Cologne (Germany), showed that despite having just 12 cycles of treatment, patients treated with venetoclax-obinutuzumab continued to experience a significant PFS benefit over those given the chemotherapy-based regimen, including in high-risk patients, after more than 6 years of follow-up.
Dr. Al-Sawaf noted that more than 50% of patients given the experimental combination remained without a PFS event at the latest follow-up, and that over 60% had not required a second treatment, equating to a 66% reduction in the likelihood of needing a second treatment versus chlorambucil-obinutuzumab.
Dr. Al-Sawaf said at a press conference that, “clinically, the standard of care for any CLL if it is asymptomatic” is watch and wait, which is “true in the frontline setting, but also in the relapse setting.”
Therefore, these patients “do not need to initiate the next line of treatment, and that’s why time to next treatment is so interesting.”
He added that there also were no new safety signals, with adverse event rates dropping markedly once treatment was over, although there was a suggestion of an increase in second malignancies with venetoclax-obinutuzumab.
“We’ve seen, in many studies now that use fixed-duration approaches, that there is virtually no posttreatment toxicity once patients are able to get off treatment,” Dr. Al-Sawaf said, adding: “This really highlights the benefit” of stopping treatment, “which is a clear advantage compared to having any kind of continuous treatment.”
Approached for comment, William G. Wierda, MD, PhD, professor, department of leukemia, division of cancer medicine, University of Texas MD Anderson Cancer Center, Houston, emphasized the value of the 6-year follow-up of the study, adding that these are “very impressive data.”
He told this news organization that, in terms of the ongoing PFS improvement, “we wouldn’t expect anything otherwise” with venetoclax-obinutuzumab when compared with the chemotherapy-based regimen, but that the trend for an improvement in overall survival is of particular interest.
This “is a notable feature of the update,” Dr. Wierda said, and “we will continue to watch the long-term overall survival curves with a longer follow-up,” especially as the separation of the curves between the two regimens is “more prominent” than in previous analyses of CLL14.
He also pointed to the low incidence of grade ≥ 3 adverse events in patients who are in remission, which “support the use of fixed-duration chemo-free” treatments, and the longer follow-up now allowing the contribution of high-risk features to outcomes to be teased out in multivariate analysis.
“The data that we’re looking for in the next update of this is some indication about improved outcomes between patients with a mutated and unmutated immunoglobulin heavy chain gene [IgHV], in regard to undetectable MRD [minimal residual disease] status,” Dr. Wierda said.
“We know that mutational status correlates with progression free survival,” he explained. “What we would like to see moving forward is how that is associated with undetectable MRD status at the end of treatment.”
Dr. Wierda said that the next hotly anticipated trial in the field is CLL17, which is comparing ibrutinib monotherapy to fixed-duration venetoclax-obinutuzumab to fixed-duration ibrutinib-venetoclax in patients with previously untreated CLL.
“That’s the next question: Is there any advantage of a BTK [Bruton’s tyrosine kinase] inhibitor with venetoclax over venetoclax plus the CD20 antibody?”
Dr. Al-Sawaf, in presenting the latest analysis, reminded the audience that CLL14 was a randomized phase 3 study focusing on patients with previously untreated CLL and coexisting conditions who were randomized to either venetoclax-obinutuzumab for six cycles, followed by six cycles of venetoclax, or chlorambucil-obinutuzumab for six cycles, followed by chlorambucil for six cycles.
The patients, who were enrolled between 2015 and 2016, were required to have a Cumulative Illness Rating Scale (CIRS) score > 6 and/or creatinine clearance < 70 mL/min, which Dr. Al-Sawaf explained serves as “indicator of the unfitness of the patients.”
A total of 432 patients took part in the study. The median age across the two treatment groups was 71-72 years, and the median total CIRS score was 8-9. The majority of patients (79%-80%) had Binet stage B or C CLL. An intermediate tumor lysis syndrome risk was identified in 64%-68%.
“We also had a fair share of patients with high-risk disease,” Dr. Al-Sawaf noted, with approximately 60% having an unmutated IGHV status, and 12% having a TP53 mutation, both of which are associated with a poorer prognosis.
He added that the “aim of these long-term observations that we try to do every year is not so much to do the comparisons to chlorambucil-obinutuzumab, which we appreciate is not necessarily a standard of care anymore,” but rather to understand the safety and effectiveness of venetoclax-obinutuzumab “in the long run, given that all patients are off treatment.”
Beginning with the safety data, Dr. Al-Sawaf showed that rates of grade ≥ 3 adverse events plummeted after the treatment period, with rates of neutropenia falling from 51.9% with venetoclax-obinutuzumab and 47.2% with chlorambucil-obinutuzumab during treatment to 3.8% and 1.9%, respectively, post treatment.
Similarly, rates of thrombocytopenia decreased from 14.2% on treatment to 0.5% off treatment in patients given venetoclax-obinutuzumab, and from 15.0% to 0.0% in the chlorambucil-obinutuzumab group.
One note of caution was sounded over the proportion of patients with at least one second primary malignancy following treatment, which was numerically higher with venetoclax-obinutuzumab, at 14.2% versus 8.4% with the chemotherapy-based regimen.
“But this is a rather a heterogeneous pattern of solid organ tumors and melanoma,” Dr. Al-Sawaf said, referring to the additional malignancies in the venetoclax-obinutuzumab arm. These included lung cancer, prostate cancer and breast cancer.
He said, however, there was no “specific pattern that we can really pinpoint ... and, importantly, the difference is not statistically significant.”
Turning to the efficacy outcomes, Dr. Al-Sawaf showed that, after median follow-up of 76.4 months, the separation in PFS between the two treatment arms continued, with the median PFS 76.2 months with venetoclax-obinutuzumab versus 36.4 months with chlorambucil-obinutuzumab, at a hazard ratio 0.40 (P < .0001).
The 6-year PFS rate in patients treated with venetoclax-obinutuzumab was 53.1% versus 21.7% with the chemotherapy-based regimen. Looking at the high-risk groups, Dr. Al-Sawaf reported that there was a similar pattern of benefit with venetoclax-obinutuzumab.
Among patients with a TP53 mutation, the median PFS was 51.9 months with the combination versus 20.8 months in those given chlorambucil-obinutuzumab, while the corresponding durations in patients with unmutated IGHV were 64.8 months and 26.9 months, respectively.
Multivariate analysis demonstrated that IGHV status was an independent predictor of PFS in patients treated with venetoclax-obinutuzumab, as was the presence of a TP53 mutation, and lymph node size ≥ 5 cm.
There was no significant difference in overall survival between the two treatment groups, although there was a numerical difference in 6-year overall survival rates, at 78.7% with the experimental combination versus 69.2% with chlorambucil-obinutuzumab.
Patients with a minimal residual disease (MRD) count ≥ 10-4 had a shorter overall survival than did those with MRD < 10-4.
“We are currently working up to understand which group of patients experiences these tremendous long term remissions,” Dr. Al-Sawaf said, “and we will keep you posted on this.”
He also showed that the time to next treatment (TTNT), defined as time to death or next anti-leukemic treatment, was significantly longer with venetoclax-obinutuzumab, with the median not reached before the current data lock versus 52.9 months with the chemotherapy-based regimen.
This equated to a hazard ratio in favor of the experimental combination of 0.44 (P < .0001), and a 6-year TTNT rate of 65.2% versus 37.1% for chlorambucil-obinutuzumab.
That second treatment was a Bruton’s tyrosine kinase inhibitor in 59.0% of cases in the venetoclax-obinutuzumab arm and 53.4% in the chlorambucil-obinutuzumab group.
Dr. Al-Sawaf noted, however, that 23.1% and 30.1%, respectively, of patients were given a chemotherapy or chemo-immunotherapy regimen, “which we nowadays would not necessarily consider a standard of care.”
“This ultimately reflects, as in many global clinical studies, the disparities that we still have across the world in terms of access to state-of-the-art therapies.”
The study was sponsored by Hoffmann–La Roche, and conducted in collaboration with AbbVie, and the German CLL Study Group. Dr. Al-Sawaf disclosed relationships with AbbVie, Adaptive, Ascentage, AstraZeneca, BeiGene, Gilead, Janssen, Lilly, and Roche.
FROM EHA 2023
‘Best’ for most APL patients: Chemo-free regimen
“In a large cohort of patients with APL, the chemo-free combination of ATRA/ATO is confirmed as the best treatment option, prolonging overall and event-free survival and reducing the relapse rate compared with ATRA/chemotherapy,” said first author Maria Teresa Voso, MD, of Tor Vergata University, in Rome, in presenting the findings at the 2023 annual meeting of the European Hematology Association.
APL, though rare, makes up about 10% of new AML cases, and the advent of the chemo-free ATRA-ATO regimen in recent years has transformed the disease, significantly improving survival.
However, with ongoing questions regarding factors associated with treatment benefits based on issues including the level of risk, Dr. Voso and colleagues turned to data from the large European Union–funded HARMONY registry, a big data project that uniquely provides real-world as well as clinical trial findings from diverse APL patient populations.
They identified 937 patients in the registry with newly diagnosed APL between 2007 and 2020 who met the study’s data quality criteria, including 536 (57.2%) patients from two clinical trials, the UK AML-17 and GIMEMA APL0406 trials, and 401 (42.8%) patients from national registries in 6 countries, representing real-world data.
The median duration of follow-up was 5.66 years, with a range of 0-14 years.
The patients had an average age of about 50, which is consistent with the lower age of diagnosis typical of APL, compared with other forms of AML.
Among them, 380 (40.6%) were treated with the ATRA-ATO regimen while 509 (54.3%) received the chemotherapy combination of ATRA-Idarubicin (AIDA).
Overall, 37.8% were determined to be low risk, as assessed by the Sanz risk-score; 42.3% were intermediate risk, and 18.7% were considered high risk. The rate of complete remission among the patients was 87.5%, and 9% had relapsed.
The results showed the 10-year overall survival (OS) rate to be 92% among the chemo-free ATRA-ATO-treated patients versus 75% in the AIDA-treated patients (P = .001).
Likewise, those treated with the chemo-free regimen had a higher event-free survival and a lower cumulative incidence of relapse (CIR) versus chemotherapy over 10 years (P < .001 for both).
In further stratifying by risk, patients who were low risk also had greater improvements with the chemo-free regimen in overall survival (P = .004), event-free survival, and CIR versus AIDA treatment (P < .001).
Among high-risk patients, however, only event-free survival was significantly improved in the chemo-free treated patients (P = .046).
Older age stood out as a significant determinant of survival, with patients in the age 50-69 and 70 or over age groups having a significantly lower rate of overall survival and event-free survival, compared with those under 50 years of age (P < .001), with those risks observed regardless of treatment type.
Age was not a significant factor in terms of the incidence of relapse (P = .159).
Clinical trial versus real-world outcomes
Of note, improved outcomes were reported in clinical trials versus real-world data, with overall survival higher in clinical trials among patients receiving the ATRA/ATO chemo-free treatment (P = .025), as well as in those receiving the AIDA chemotherapy (P < .001).
Early death, an uncommon but key concern with APL, usually due to bleeding complications and defined as death occurring within 30 days from APL diagnosis, occurred among 56 patients, or 5.9%, overall, and was significantly higher in the age 50-69 and over 70 groups versus those under 50 (P < .001).
Early death was more common among those with a Sanz high-risk score (15.4%), compared with low or intermediate risk (3.9%; P < .001); however, the risk was no different between the chemo-free (3.4%) and chemotherapy (5.7%) groups, regardless of whether patients had a low or high risk.
The rates of early death were significantly higher in the real-world population (10.2%), compared with patients in clinical trials (2.8%; P < .001), which Dr. Voso noted may be expected, as early deaths in some cases can occur even before a diagnosis is made.
“These patients sometimes come to the ER and if a diagnosis is not made, they may die before even receiving treatment,” she said in a press briefing.
“Indeed, the median time to death among those who had early death in the study was only 10 days, and there were even some patients dying at day 0,” she explained.
“So, it’s very important that not only hematologists but emergency doctors recognize this disease and try to reduce the early death rate.”
Overall, the results all remained consistent after adjustment in a multivariate analysis, Dr. Voso said.
“The multivariate analysis confirmed that increasing age, high Sanz risk score, the real-life treatment scenario, and the chemotherapy-based approach are independently associated with decreased survival,” she said.
The findings underscore that “elderly age and high Sanz risk score significantly impact on the rate of early deaths, irrespective of treatment,” Dr. Voso said.
ATRA/ATO ‘gold standard’ for low/intermediate risk
Commenting on the study, Alessandro Isidori, MD, PhD, a hematologist at AORMN Hospital, in Pesaro, Italy, who moderated the session, noted that the study underscores the greater challenges with higher-risk patients.
“The study did not show a statistical benefit for high-risk patients receiving ATRA/ATO versus AIDA,” he told this news organization, noting that “currently, there are many countries where ATRA/ATO is not approved for use in high-risk APL.”
“In high-risk APL, the AIDA combination should still be preferred to ATRA/ATO,” he said.
Dr. Isidori recommended careful efforts to stratify higher-risk patients who still may benefit from ATRA/ATO.
“The analysis of high-risk patients with white blood cell count as a continuous variable instead of a fixed variable (more or less than 10,000/mmc) may help to discriminate some high-risk patients who could benefit from ATRA/ATO,” he noted.
Overall, however, “ATRA/ATO is the gold standard for low and intermediate risk APL,” he said.
“Although promising, more data are needed to confirm the efficacy of ATRA/ATO in high-risk APL.”
Dr. Voso disclosed ties with companies including Celgene/Bristol Myers Squibb, Astellas, Jazz Pharmaceuticals, Abbvie, Novartis, and AstraZeneca. Dr. Isidori reported no disclosures.
“In a large cohort of patients with APL, the chemo-free combination of ATRA/ATO is confirmed as the best treatment option, prolonging overall and event-free survival and reducing the relapse rate compared with ATRA/chemotherapy,” said first author Maria Teresa Voso, MD, of Tor Vergata University, in Rome, in presenting the findings at the 2023 annual meeting of the European Hematology Association.
APL, though rare, makes up about 10% of new AML cases, and the advent of the chemo-free ATRA-ATO regimen in recent years has transformed the disease, significantly improving survival.
However, with ongoing questions regarding factors associated with treatment benefits based on issues including the level of risk, Dr. Voso and colleagues turned to data from the large European Union–funded HARMONY registry, a big data project that uniquely provides real-world as well as clinical trial findings from diverse APL patient populations.
They identified 937 patients in the registry with newly diagnosed APL between 2007 and 2020 who met the study’s data quality criteria, including 536 (57.2%) patients from two clinical trials, the UK AML-17 and GIMEMA APL0406 trials, and 401 (42.8%) patients from national registries in 6 countries, representing real-world data.
The median duration of follow-up was 5.66 years, with a range of 0-14 years.
The patients had an average age of about 50, which is consistent with the lower age of diagnosis typical of APL, compared with other forms of AML.
Among them, 380 (40.6%) were treated with the ATRA-ATO regimen while 509 (54.3%) received the chemotherapy combination of ATRA-Idarubicin (AIDA).
Overall, 37.8% were determined to be low risk, as assessed by the Sanz risk-score; 42.3% were intermediate risk, and 18.7% were considered high risk. The rate of complete remission among the patients was 87.5%, and 9% had relapsed.
The results showed the 10-year overall survival (OS) rate to be 92% among the chemo-free ATRA-ATO-treated patients versus 75% in the AIDA-treated patients (P = .001).
Likewise, those treated with the chemo-free regimen had a higher event-free survival and a lower cumulative incidence of relapse (CIR) versus chemotherapy over 10 years (P < .001 for both).
In further stratifying by risk, patients who were low risk also had greater improvements with the chemo-free regimen in overall survival (P = .004), event-free survival, and CIR versus AIDA treatment (P < .001).
Among high-risk patients, however, only event-free survival was significantly improved in the chemo-free treated patients (P = .046).
Older age stood out as a significant determinant of survival, with patients in the age 50-69 and 70 or over age groups having a significantly lower rate of overall survival and event-free survival, compared with those under 50 years of age (P < .001), with those risks observed regardless of treatment type.
Age was not a significant factor in terms of the incidence of relapse (P = .159).
Clinical trial versus real-world outcomes
Of note, improved outcomes were reported in clinical trials versus real-world data, with overall survival higher in clinical trials among patients receiving the ATRA/ATO chemo-free treatment (P = .025), as well as in those receiving the AIDA chemotherapy (P < .001).
Early death, an uncommon but key concern with APL, usually due to bleeding complications and defined as death occurring within 30 days from APL diagnosis, occurred among 56 patients, or 5.9%, overall, and was significantly higher in the age 50-69 and over 70 groups versus those under 50 (P < .001).
Early death was more common among those with a Sanz high-risk score (15.4%), compared with low or intermediate risk (3.9%; P < .001); however, the risk was no different between the chemo-free (3.4%) and chemotherapy (5.7%) groups, regardless of whether patients had a low or high risk.
The rates of early death were significantly higher in the real-world population (10.2%), compared with patients in clinical trials (2.8%; P < .001), which Dr. Voso noted may be expected, as early deaths in some cases can occur even before a diagnosis is made.
“These patients sometimes come to the ER and if a diagnosis is not made, they may die before even receiving treatment,” she said in a press briefing.
“Indeed, the median time to death among those who had early death in the study was only 10 days, and there were even some patients dying at day 0,” she explained.
“So, it’s very important that not only hematologists but emergency doctors recognize this disease and try to reduce the early death rate.”
Overall, the results all remained consistent after adjustment in a multivariate analysis, Dr. Voso said.
“The multivariate analysis confirmed that increasing age, high Sanz risk score, the real-life treatment scenario, and the chemotherapy-based approach are independently associated with decreased survival,” she said.
The findings underscore that “elderly age and high Sanz risk score significantly impact on the rate of early deaths, irrespective of treatment,” Dr. Voso said.
ATRA/ATO ‘gold standard’ for low/intermediate risk
Commenting on the study, Alessandro Isidori, MD, PhD, a hematologist at AORMN Hospital, in Pesaro, Italy, who moderated the session, noted that the study underscores the greater challenges with higher-risk patients.
“The study did not show a statistical benefit for high-risk patients receiving ATRA/ATO versus AIDA,” he told this news organization, noting that “currently, there are many countries where ATRA/ATO is not approved for use in high-risk APL.”
“In high-risk APL, the AIDA combination should still be preferred to ATRA/ATO,” he said.
Dr. Isidori recommended careful efforts to stratify higher-risk patients who still may benefit from ATRA/ATO.
“The analysis of high-risk patients with white blood cell count as a continuous variable instead of a fixed variable (more or less than 10,000/mmc) may help to discriminate some high-risk patients who could benefit from ATRA/ATO,” he noted.
Overall, however, “ATRA/ATO is the gold standard for low and intermediate risk APL,” he said.
“Although promising, more data are needed to confirm the efficacy of ATRA/ATO in high-risk APL.”
Dr. Voso disclosed ties with companies including Celgene/Bristol Myers Squibb, Astellas, Jazz Pharmaceuticals, Abbvie, Novartis, and AstraZeneca. Dr. Isidori reported no disclosures.
“In a large cohort of patients with APL, the chemo-free combination of ATRA/ATO is confirmed as the best treatment option, prolonging overall and event-free survival and reducing the relapse rate compared with ATRA/chemotherapy,” said first author Maria Teresa Voso, MD, of Tor Vergata University, in Rome, in presenting the findings at the 2023 annual meeting of the European Hematology Association.
APL, though rare, makes up about 10% of new AML cases, and the advent of the chemo-free ATRA-ATO regimen in recent years has transformed the disease, significantly improving survival.
However, with ongoing questions regarding factors associated with treatment benefits based on issues including the level of risk, Dr. Voso and colleagues turned to data from the large European Union–funded HARMONY registry, a big data project that uniquely provides real-world as well as clinical trial findings from diverse APL patient populations.
They identified 937 patients in the registry with newly diagnosed APL between 2007 and 2020 who met the study’s data quality criteria, including 536 (57.2%) patients from two clinical trials, the UK AML-17 and GIMEMA APL0406 trials, and 401 (42.8%) patients from national registries in 6 countries, representing real-world data.
The median duration of follow-up was 5.66 years, with a range of 0-14 years.
The patients had an average age of about 50, which is consistent with the lower age of diagnosis typical of APL, compared with other forms of AML.
Among them, 380 (40.6%) were treated with the ATRA-ATO regimen while 509 (54.3%) received the chemotherapy combination of ATRA-Idarubicin (AIDA).
Overall, 37.8% were determined to be low risk, as assessed by the Sanz risk-score; 42.3% were intermediate risk, and 18.7% were considered high risk. The rate of complete remission among the patients was 87.5%, and 9% had relapsed.
The results showed the 10-year overall survival (OS) rate to be 92% among the chemo-free ATRA-ATO-treated patients versus 75% in the AIDA-treated patients (P = .001).
Likewise, those treated with the chemo-free regimen had a higher event-free survival and a lower cumulative incidence of relapse (CIR) versus chemotherapy over 10 years (P < .001 for both).
In further stratifying by risk, patients who were low risk also had greater improvements with the chemo-free regimen in overall survival (P = .004), event-free survival, and CIR versus AIDA treatment (P < .001).
Among high-risk patients, however, only event-free survival was significantly improved in the chemo-free treated patients (P = .046).
Older age stood out as a significant determinant of survival, with patients in the age 50-69 and 70 or over age groups having a significantly lower rate of overall survival and event-free survival, compared with those under 50 years of age (P < .001), with those risks observed regardless of treatment type.
Age was not a significant factor in terms of the incidence of relapse (P = .159).
Clinical trial versus real-world outcomes
Of note, improved outcomes were reported in clinical trials versus real-world data, with overall survival higher in clinical trials among patients receiving the ATRA/ATO chemo-free treatment (P = .025), as well as in those receiving the AIDA chemotherapy (P < .001).
Early death, an uncommon but key concern with APL, usually due to bleeding complications and defined as death occurring within 30 days from APL diagnosis, occurred among 56 patients, or 5.9%, overall, and was significantly higher in the age 50-69 and over 70 groups versus those under 50 (P < .001).
Early death was more common among those with a Sanz high-risk score (15.4%), compared with low or intermediate risk (3.9%; P < .001); however, the risk was no different between the chemo-free (3.4%) and chemotherapy (5.7%) groups, regardless of whether patients had a low or high risk.
The rates of early death were significantly higher in the real-world population (10.2%), compared with patients in clinical trials (2.8%; P < .001), which Dr. Voso noted may be expected, as early deaths in some cases can occur even before a diagnosis is made.
“These patients sometimes come to the ER and if a diagnosis is not made, they may die before even receiving treatment,” she said in a press briefing.
“Indeed, the median time to death among those who had early death in the study was only 10 days, and there were even some patients dying at day 0,” she explained.
“So, it’s very important that not only hematologists but emergency doctors recognize this disease and try to reduce the early death rate.”
Overall, the results all remained consistent after adjustment in a multivariate analysis, Dr. Voso said.
“The multivariate analysis confirmed that increasing age, high Sanz risk score, the real-life treatment scenario, and the chemotherapy-based approach are independently associated with decreased survival,” she said.
The findings underscore that “elderly age and high Sanz risk score significantly impact on the rate of early deaths, irrespective of treatment,” Dr. Voso said.
ATRA/ATO ‘gold standard’ for low/intermediate risk
Commenting on the study, Alessandro Isidori, MD, PhD, a hematologist at AORMN Hospital, in Pesaro, Italy, who moderated the session, noted that the study underscores the greater challenges with higher-risk patients.
“The study did not show a statistical benefit for high-risk patients receiving ATRA/ATO versus AIDA,” he told this news organization, noting that “currently, there are many countries where ATRA/ATO is not approved for use in high-risk APL.”
“In high-risk APL, the AIDA combination should still be preferred to ATRA/ATO,” he said.
Dr. Isidori recommended careful efforts to stratify higher-risk patients who still may benefit from ATRA/ATO.
“The analysis of high-risk patients with white blood cell count as a continuous variable instead of a fixed variable (more or less than 10,000/mmc) may help to discriminate some high-risk patients who could benefit from ATRA/ATO,” he noted.
Overall, however, “ATRA/ATO is the gold standard for low and intermediate risk APL,” he said.
“Although promising, more data are needed to confirm the efficacy of ATRA/ATO in high-risk APL.”
Dr. Voso disclosed ties with companies including Celgene/Bristol Myers Squibb, Astellas, Jazz Pharmaceuticals, Abbvie, Novartis, and AstraZeneca. Dr. Isidori reported no disclosures.
FROM EHA 2023