Etentamig Phase 3 BLA Challenges Entrenched BCMA Bispecifics Without Survival Proof

AbbVie Submits BLA for Etentamig in Relapsed/Refractory Multiple Myeloma

AbbVie has submitted a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) for etentamig, a second-generation BCMA x CD3 bispecific antibody T-cell engager. This submission targets the treatment of adults with relapsed or refractory multiple myeloma. The BLA is supported by positive results from the Phase 3 CERVINO study, which demonstrated statistically significant improvements in overall response rate (74.0% vs. 45.7%) and progression-free survival (60% risk reduction) compared to standard available therapies. Etentamig also showed a potentially differentiated safety profile, including a low incidence of Grade 3 or higher cytokine release syndrome, and offers the convenience of a monthly dosing schedule, aiming to address the complex needs of patients with this chronic blood cancer.

• AbbVie has submitted a Biologics License Application (BLA) to the U.S. FDA for etentamig, an investigational, second-generation BCMA x CD3 bispecific antibody T-cell engager. This intravenous therapy is intended for adults with relapsed or refractory multiple myeloma. The submission highlights etentamig's potential to offer a novel, patient-centered treatment option with a manageable safety profile and the convenience of a monthly dosing schedule, addressing the need for effective treatment delivery across diverse care environments.
• The BLA is supported by robust data from the global, Phase 3 CERVINO study. Etentamig achieved statistically significant improvements in its dual primary endpoints: overall response rate (ORR) of 74.0% compared to 45.7% for investigator's choice of standard available therapies (SAT), and a 60% risk reduction in progression-free survival (PFS) versus SAT. These efficacy findings underscore etentamig's strong anti-myeloma activity in a challenging patient population of triple-class exposed relapsed or refractory multiple myeloma.
• Etentamig demonstrated a potentially differentiated safety profile, particularly concerning cytokine release syndrome (CRS) and infections. Among patients receiving a single step-up dose, the incidence of CRS was low (28.3%), with all events being Grade 1 (23.9%) or Grade 2 (4.4%), and no Grade 3 or higher events reported. Grade 5 infections were also observed less frequently with etentamig (1.5%) compared to SAT (3.1%). The optimized dosing strategy incorporates a single step-up dose followed by convenient monthly (Q4W) administration from initiation.

Addressing the Unmet Needs in Relapsed/Refractory Multiple Myeloma

Relapsed/refractory multiple myeloma remains incurable with high relapse rates, worsening prognosis and reduced survival despite BCMA-targeting therapeutics delivering deep responses. Acquired drug resistance inevitably emerges and drives disease progression, while patient heterogeneity and prior treatment exposure further complicate durable disease control.

• Antigen escape and shared cross-resistance between BCMA-directed therapies: Loss of plasma cell BCMA expression following TNFRSF17 gene deletions can occur following any BCMA-directed therapy and prevents response to subsequent anti-BCMA-directed treatments. Prior therapy-mediated loss of plasma cell BCMA expression before teclistamab treatment, measured by immunohistochemistry, was observed in 3 patients, none of whom responded to teclistamab, and 1 of whom also did not respond to ciltacabtagene autoleucel, with whole exome sequencing revealing biallelic loss of TNFRSF17 following treatment with belantamab mafodotin. Low-to-undetectable peripheral blood soluble BCMA levels correlated with the absence of BCMA expression by bone marrow plasma cells, underscoring the importance of verifying the presence of a target antigen.

• Distinct and persistent toxicity burden limiting broader use: Chimeric antigen receptor T cell therapies present cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), non-ICANS neurotoxicity, cytopenias, infections, and hypogammaglobulinemia. Bispecific antibodies are associated with CRS in up to two thirds of patients with ICANS in rare cases, with CRS occurring in 72% and neurologic toxicity in 57% including immune effector cell-associated neurotoxicity syndrome in 6% in MajesTEC-1, while infection risk persists throughout bispecific antibody therapy and is the leading cause of nonrelapse mortality, particularly with B-cell maturation antigen-targeting bispecific antibodies, due to profound B-cell and plasma cell depletion, resulting in near-universal hypogammaglobulinemia.

• Inferior outcomes in frail, elderly and biologically high-risk populations: Of 136 patients analyzed (age range, 41 to 81 years), 83 (61%) were considered frail at time of CAR-T infusion, with median progression-free survival of 6.9 months in the frail group versus 11.1 months in the nonfrail group and median overall survival of 14 months in the frail group and not reached in the nonfrail group, despite similar incidences of all-grade CRS and high-grade CRS and ICANS. Challenging features include high-risk cytogenetics, renal impairment, patient characteristics such as age and frailty, and extramedullary disease, with patients with ultra-high-risk disease having a median PFS of <24 months with current standard of care that includes consolidation with autologous hematopoietic stem cell transplantation.

• Treatment refractoriness and compromised sequencing after prior BCMA exposure: In a retrospective cohort of 283 patients with minimum of 5 lines of therapy, 35.7% of patients have an overall response rate with median response duration of 6.3 months, with most categorized in penta-refractory class (33.6%), followed by triple-refractory (25.4%), dual-refractory (19.4%), and not triple-refractory classes (13.4%). Prior BCMA exposure reduced depth of response, with inferior overall survival observed in those treated within one year of prior therapy, and emerging evidence supports prioritizing chimeric antigen receptor T-cell therapy before bispecific antibodies when clinically feasible, as sequential efficacy appears compromised in the reverse sequence.

• Logistical and durability constraints of T-cell redirecting platforms: Bispecific antibody therapies like teclistamab and elranatamab may lead to T-cell exhaustion, while CAR-T therapies achieve high response rates and rapid minimal residual disease negativity but wider use is limited by manufacturing time, toxicity management, and relapse mechanisms such as antigen loss, poor persistence of CAR-T cells, and the complicated tumor microenvironment. High manufacturing costs and time-consuming manufacturing processes caused by personalized manufacturing procedures also limit broad clinical application, alongside logistical issues related to step-up dosing and cytokine release syndrome.

Pivotal CERVINO Study Results Support Etentamig BLA

Recent studies in relapsed and refractory multiple myeloma (RRMM) have evaluated BCMA-directed CAR T-cell therapies and bispecific antibodies in heavily pretreated, triple-class exposed populations. Efficacy signals include high overall response rates with deepening responses over time, alongside prolonged progression-free survival and overall survival. Safety profiles are characterized by cytopenias, cytokine release syndrome, neurotoxicity, and infections.

Etentamig's Differentiated Safety and Dosing Profile

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Etentamig's BLA: A Differentiated Play in Relapsed Myeloma

The submission of a Biologics License Application for etentamig marks a significant development for patients battling relapsed or refractory multiple myeloma (RRMM). This chronic and aggressive blood cancer continues to present substantial challenges, with patients often progressing through multiple lines of therapy and facing a diminishing array of effective, tolerable options. Etentamig, a second-generation BCMA x CD3 bispecific antibody, aims to address this critical unmet need by redirecting T-cells to target myeloma cells expressing BCMA.

The Phase 3 CERVINO study results supporting this BLA are compelling. Studies indicate a statistically significant improvement in overall response rate, reaching 74.0%, and a remarkable 60% reduction in the risk of progression or death compared to standard available therapies. Beyond efficacy, etentamig's potentially differentiated safety profile is a key highlight, demonstrating a low incidence of Grade 3 or higher cytokine release syndrome (CRS), a common and often challenging toxicity associated with T-cell engaging therapies. This improved tolerability, coupled with the convenience of a monthly dosing schedule, could significantly enhance the patient experience and expand the accessibility of highly effective treatment options.

However, the path to market leadership is not without hurdles. The BCMA-targeted landscape is rapidly evolving and increasingly competitive, with several approved and investigational agents vying for market share. While etentamig's safety and convenience profile offers a strong differentiator, long-term safety data, particularly concerning neurotoxicity and infection risk, and the durability of response will be crucial for sustained adoption. Furthermore, as with many novel oncology therapies, potential access and reimbursement challenges due to high costs could impact broad patient uptake. Despite these considerations, etentamig's BLA represents a promising step forward, potentially offering a new, differentiated option that could reshape the treatment paradigm for patients with relapsed or refractory multiple myeloma, providing both potent efficacy and a more manageable treatment experience.