according to results of a randomized, phase 3 trial.
Dr. Michael R. Bishop
The chimeric antigen receptor (CAR) T-cell therapy did not improve event-free survival (EFS) in this phase 3 BELINDA study, potentially because of study design decisions or imbalances in relevant patient characteristics, according to the study investigators.
Despite the negative result, insights from this study will inform the development of future clinical trials of CAR T-cell therapy, said BELINDA investigator Michael R. Bishop, MD, of the David and Etta Jonas Center for Cellular Therapy, University of Chicago.
Findings of BELINDA, presented at the annual meeting of the American Society of Hematology, stand in contrast to two other high-profile CAR T-cell therapy studies also presented at the meeting. Those other studies demonstrated significant improvements in EFS in the second-line treatment of large B-cell lymphomas.
“All of us are excited to see that the other two trials were positive, and we were hoping that ours would be as well, but there are significant differences in the trial design,” Dr. Bishop said in a press conference held at the ASH meeting.
Tisagenlecleucel (tisa-cel), an anti-CD19 CAR T-cell therapy, is already approved by the Food and Drug Administration for the treatment of patients with relapsed or refractory large B-cell lymphomas after at least two other lines of systemic therapy.
The aim of the pivotal phase 3, randomized, multicenter BELINDA study was to evaluate tisa-cel earlier in the course of treatment for patients with more aggressive disease, according to Dr. Bishop.
About two-thirds of non-Hodgkin lymphoma patients will be cured with first-line treatment. However, very poor outcomes are seen among patients with disease that does not respond to the initial treatment or that reoccurs shortly afterward, Dr. Bishop said.
The standard of care approach for those patients is second-line therapy, he noted, usually with combination chemoimmunotherapy, followed by autologous stem cell transplant if the disease responds to chemotherapy.
“Unfortunately, only a minority of those patients will be found to have chemotherapy-sensitive disease and be able to go on to autologous stem cell transplantation,” Dr. Bishop said. “And even in that subgroup of patients, the outcomes are relatively poor.”
Accordingly, the phase 3 BELINDA study enrolled patients with aggressive non-Hodgkin lymphomas that either did not respond to first-line treatment or that reoccurred within 12 months.
The primary endpoint of the study was EFS, defined as the time from randomization to either stable or progressive disease at or after a week 12 assessment or to any-cause death at any time.
While that primary endpoint was not met for tisa-cel versus standard of care therapy, two other randomized, phase 3 studies presented at the ASH meeting did demonstrate that CAR T-cell therapy extended EFS when given as a second-line lymphoma treatment.
In the randomized, phase 3 ZUMA-7 trial, axicabtagene ciloleucel (axi-cel) significantly improved EFS versus standard of care in the treatment of patients with large B-cell lymphoma refractory to or relapsed within 12 months of adequate first-line therapy, according to investigators.
Similarly, the investigators said that treatment with lisocabtagene maraleucel (liso-cel) led to a significant improvement in EFS in TRANSFORM, a randomized, phase 3 clinical trial that enrolled patients with large B-cell lymphoma that was refractory to first-line therapy or else relapsed within 12 months of that treatment.
“It’s very possible that either or both the patient characteristics and the study design is what led to the difference in the top-line study results,” lymphoma specialist Andrew M. Evens, DO, said in an interview.
There were substantial differences between the studies in terms of what was allowed as optional bridging therapy and salvage therapy, according to Dr. Evens, associate director for clinical services and director of the lymphoma program at Rutgers Cancer Institute in New Brunswick, N.J.
“In ZUMA-7, they only allowed steroids as bridging therapy,” said Dr. Evens, who was not an investigator on any of the three second-line CAR T-cell studies.
In the BELINDA study, optional platinum-based chemotherapy bridging treatment allowed in one arm of the study could have potentially delayed tisa-cel infusion until after the week 6 assessment, study investigators reported in their ASH meeting abstract.
Differences in lymphodepleting therapy prior to CAR T-cell therapy could have also played a role. According to Dr. Bishop, the total doses of cyclophosphamide and fludarabine in BELINDA were 900 mg/m2 and 75 mg/m2, respectively, while in the other two trials, doses were 1,500 mg/m2 and 90 mg/m2, respectively.
Lymphodepleting chemotherapy is “extremely important” in the success of CAR T-cell therapeutic approaches, he noted at the press conference.
Dr. Bishop reported receiving consultancy fees from Arcellx, Autolus Therapeutics, Bristol-Myers Squibb, CRISPR, Kite/Gilead, and Novartis. He also reported research funding from Bristol-Myers Squibb and Kite/Gilead.