On December 12, 2023 Bristol Myers Squibb (NYSE: BMY) and 2seventy bio, Inc. (Nasdaq: TSVT) reported results from the preplanned final progression-free survival (PFS) analysis of KarMMa-3, the pivotal Phase 3, open-label, global, randomized controlled study evaluating Abecma (idecabtagene vicleucel) compared with standard combination regimens in adults with relapsed and refractory multiple myeloma after two to four prior lines of therapy, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody (triple-class exposed), who were refractory to their last regimen (Press release, 2seventy bio, DEC 12, 2023, View Source [SID1234638479]). At a median follow-up of 30.9 months (range: 12.7-47.8), representing the longest follow-up for a randomized Phase 3 CAR T cell therapy trial in this patient population, significantly improved PFS was maintained with Abecma compared to standard regimens (95% CI: 13.8 months vs. 4.4 months), with a 51% reduction in the risk of disease progression or death (HR: 0.49; 95% CI: 0.38-0.63). These data are being presented today in an oral presentation at the 65th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition (Oral Presentation #1028).

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With extended follow-up, treatment with Abecma (n=254) continued to demonstrate higher overall response rates (ORR) and a deepening of responses versus standard regimens. The ORR with Abecma was 71% (95% CI: 66-77) with a complete response (CR) rate of 44% (95% CI: 38-50), which increased by 5% from the interim analysis. In comparison, the ORR for standard regimens was 41% (95% CI: 34-51), with a CR rate of 5% (95% CI: 2-9), which remained unchanged from the time of interim analysis. The PFS, ORR and CR rates observed in the KarMMa-3 trial in the standard regimens arm are consistent with those that have historically been observed in this heavily pre-treated triple-class exposed patient population, in which PFS is approximately four months and deep and durable responses are limited. With these data, Abecma is the first and only anti-BCMA CAR T cell therapy to demonstrate superiority over standard regimens in a randomized, controlled Phase 3 trial designed to evaluate patients with triple-class exposed relapsed and refractory multiple myeloma.

"With longer follow-up from the KarMMa-3 study, we continue to see the significant clinical benefit that Abecma delivers for triple-class exposed multiple myeloma, illustrating the potential of using Abecma for long-term disease control and remission when used earlier in the treatment paradigm," said Paula Rodriguez-Otero, M.D., Ph.D., Department of Hematology, Clinica Universidad de Navarra, Pamplona, Spain. "As the CAR T therapy with the longest real-world experience in later lines of therapy, and with these latest data which demonstrate clinically meaningful benefit and awell-established and generally predictable safety profile, Abecma has the potential to be a transformative treatment option across lines of therapy for triple-class exposed relapsed and refractory multiple myeloma."

"As the first-in-class anti-BCMA CAR T cell therapy, we have long believed in the clinical value Abecma can deliver across the treatment paradigm for multiple myeloma, transforming outcomes for patients with a relentless disease and continued unmet need," said Anne Kerber, senior vice president, Head of Late Clinical Development, Hematology, Oncology, and Cell Therapy, Bristol Myers Squibb. "These longer-term results from the KarMMa-3 trial clearly demonstrate the potential of Abecma to be an important treatment option to provide improved progression-free survival and durable responses in patients with relapsed and refractory multiple myeloma after being treated with the three main classes of therapy. We are proud to share these data which further advance the use of cell therapies as a new standard of care for more patients in earlier lines of therapy for difficult-to-treat blood cancers."
In the study, which included a patient-centric design that allowed for crossover from standard regimens to Abecma upon confirmed disease progression, overall survival (OS) was a key secondary endpoint. Due to the median PFS observed with standard regimens, more than half (56%) of patients in the standard regimens arm crossed over to receive Abecma as a subsequent therapy. The median OS was 41.4 months with Abecma (95% CI: 30.9-NR) and 37.9 months with standard regimens (95% CI: 23.4-NR) (95% CI: 0.73-1.40; HR: 1.01). However, the prespecified sensitivity analyses adjusting for crossover showed a median OS of 41.4 months for Abecma (95% CI: 30.9-NR) and 23.4 months (95% CI: 17.9-NR) for standard regimens (95% CI: 0.45-1.09; HR: 0.69), suggesting a positive trend in OS benefit for Abecma compared with standard regimens. Historically, based on real-world evidence, median OS for patients with triple-class exposed relapsed and refractory multiple myeloma is approximately 13 months.

"With the adjustments for crossover in the KarMMa-3 study, we clearly see the consistent trend in survival benefit that this anti-BCMA CAR T cell therapy delivers, introducing the potential for Abecma to be an important treatment option for these patients," said Sergio Giralt, M.D., Division of Hematologic Malignancies, Memorial Sloan Kettering Cancer Center. "These results show remarkable and significantly improved durable outcomes for relapsing triple-class exposed multiple myeloma patients, which is a population that has had poor overall and progression-free survival and no established standard treatment approach that provides durable responses."
"It’s important to bear in mind that management of relapsed refractory multiple myeloma remains challenging; patients are becoming triple-class

exposed earlier in their treatment course and then developing disease that is resistant to existing therapies," said Steve Bernstein, M.D., chief medical officer, 2seventy bio. "We are excited that these positive results from the KarMMa-3 study demonstrate a significant clinical benefit of Abecma across lines of care in triple-class exposed multiple myeloma and look forward to the potential of expanding the benefits of Abecma to these patients earlier in their treatment course."

In the KarMMa-3 study, Abecma continued to exhibit a well-established and generally predictable safety profile, including no new safety signals, with mostly low-grade occurrences of cytokine release syndrome (CRS) and neurotoxicity. In patients treated with Abecma with extended follow-up, occurrences of CRS and neurologic toxicities remained consistent with the interim analysis with 88% of patients experiencing any grade CRS, and Grade 3/4 CRS events occurring in 4% of patients. Two patients (1%) experienced a Grade 5 CRS event. Any grade neurotoxicity occurred in 15% of patients, with Grade 3/4 neurotoxicity occurring in 3% of patients, and no Grade 5 events reported.

Abecma was recently approved in Japan for patients with relapsed or refractory multiple myeloma who have received at least two prior therapies, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 antibody based on the KarMMa-3 study, making it the first CAR T to receive regulatory approval for use in earlier lines of therapy for patients with relapsed or refractory multiple myeloma. A supplemental Biologics License Application for Abecma based on the KarMMa-3 results is currently under review with the U.S. Food and Drug Administration (FDA), and an Oncologic Drugs Advisory Committee meeting will be held to discuss the data. Regulatory applications for Abecma in earlier lines of therapy for triple-class exposed relapsed and refractory multiple myeloma are also under review with the European Medicines Agency and Swissmedic.

Results from Extended Follow-up for Cohort 2c of the KarMMa-2 Study

Results from extended follow-up for Cohort 2c of the multicohort, Phase 2, multicenter KarMMa-2 study, evaluating Abecma in patients with multiple myeloma who had an inadequate response to frontline therapy with autologous stem cell transplantation (ASCT) are also being presented in a poster presentation (Poster Presentation #2101) at the meeting. At data cutoff with a median follow-up of 39.4 months, the ORR in patients treated with Abecma (n=31) was 87.1% (95% CI: 70.2-96.4), with a CR rate of 77.4% (95% CI: 58.9-90.4). Median duration of response, median PFS and median OS were not reached, and all patients who received Abecma (n=31) remained alive at follow-up. Safety results were generally consistent with the well-established known safety profile of Abecma, with any grade CRS occurring in 58.1% of patients and no reports of Grade >3 CRS.
Abecma is the first-in-class B-cell maturation antigen (BCMA)-directed CAR T cell immunotherapy approved by the FDA for the treatment of adult patients with relapsed or refractory multiple myeloma after four or more prior lines of therapy, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody. Please see the Important Safety Information section below, including Boxed WARNINGS for Abecma regarding CRS, neurologic toxicities, Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome and Prolonged Cytopenia. Abecma is also approved in the European Union, Switzerland, Canada, the United Kingdom and Israel for adult patients with triple-class exposed relapsed or refractory multiple myeloma after three to four or more prior lines of therapy.

Memorial Sloan Kettering Cancer Center disclosures: Dr. Giralt and Memorial Sloan Kettering Cancer Center have financial interests associated with the research described in this release.

About KarMMa-3

KarMMa-3 (NCT03651128) is a pivotal, Phase 3, open-label, global, randomized, controlled trial evaluating Abecma compared to standard regimens in patients with relapsed and refractory multiple myeloma who have received two to four prior lines of treatment, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody, and were refractory to the last treatment regimen. Patients were randomized to receive Abecma or standard regimens that consisted of combinations that included daratumumab, pomalidomide, and dexamethasone (DPd), daratumumab, bortezomib, and dexamethasone (DVd), ixazomib, lenalidomide, and dexamethasone (IRd), carfilzomib and dexamethasone (Kd) or elotuzumab, pomalidomide and dexamethasone (EPd) chosen based on their most recent treatment regimen and investigator discretion. The primary endpoint evaluated in this study is progression-free survival (PFS), defined as time from randomization to the first documentation of progressive disease or death due to any cause, whichever occurs first. Key secondary endpoints include overall response rate (ORR) and overall survival (OS).

About KarMMa-2

KarMMa-2 (NCT03601078) is a Phase 2, open-label, multicohort, multicenter study evaluating the efficacy and safety of Abecma in patients with relapsed and refractory multiple myeloma (Cohort 1), patients with multiple myeloma that has progressed within 18 months of initial treatment including autologous stem cell transplantation (ASCT) (Cohort 2a), or without ASCT (Cohort 2b) or, in patients with inadequate response post-ASCT during initial treatment (Cohort 2c), and patients with newly diagnosed multiple myeloma with suboptimal response to ASCT (Cohort 3). The primary endpoints evaluated in this study are ORR in Cohort 1 and complete response (CR) rate in Cohorts 2a, b, c and Cohort 3. Key secondary endpoints include CR rate in Cohort 1, ORR in Cohorts 2a, b, c and Cohort 3, duration of response, PFS and OS.

About Abecma

Abecma recognizes and binds to BCMA on the surface of multiple myeloma cells leading to CAR T cell proliferation, cytokine secretion, and subsequent cytolytic killing of BCMA-expressing cells. Abecma is being jointly developed and commercialized in the U.S. as part of a
Co-Development, Co-Promotion, and Profit Share Agreement between Bristol Myers Squibb and 2seventy bio.
The companies’ broad clinical development program for Abecma includes clinical studies (KarMMa-2, KarMMa-3, KarMMa-9) in earlier lines of treatment for patients with multiple myeloma. For more information visit clinicaltrials.gov.
Important Safety Information

BOXED WARNING: CYTOKINE RELEASE SYNDROME, NEUROLOGIC TOXICITIES, HLH/MAS, AND PROLONGED CYTOPENIA

•Cytokine Release Syndrome (CRS), including fatal or life-threatening reactions, occurred in patients following treatment with ABECMA. Do not administer ABECMA to patients with active infection or inflammatory disorders. Treat severe or life-threatening CRS with tocilizumab or tocilizumab and corticosteroids.
•Neurologic Toxicities, which may be severe or life-threatening, occurred following treatment with ABECMA, including concurrently with CRS, after CRS resolution, or in the absence of CRS. Monitor for neurologic events after treatment with ABECMA. Provide supportive care and/or corticosteroids as needed.
•Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome (HLH/MAS) including fatal and life-threatening reactions, occurred in patients following treatment with ABECMA. HLH/MAS can occur with CRS or neurologic toxicities.
•Prolonged Cytopenia with bleeding and infection, including fatal outcomes following stem cell transplantation for hematopoietic recovery, occurred following treatment with ABECMA. ABECMA is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the ABECMA REMS.