e19525 Background: BCMA-directed CAR T cell therapies and bispecific antibodies (BsAbs) have transformed outcomes for patients with relapsed/refractory multiple myeloma (RRMM). As these therapies move earlier in treatment, an increasing proportion of patients relapse after exposure to one or both T-cell–redirecting modalities. Real-world evidence to guide treatment selection in this setting remains limited, creating uncertainty in clinical practice. Methods: A mixed-methods market research study surveyed 61 hematologist/oncologists from academic (43%, n = 26) and community (57%, n = 35) practices across the U.S. using a structured online questionnaire, supplemented by qualitative interviews conducted via web-based videoconferencing. Fieldwork occurred between October and November 2025. Quantitative measures assessed treatment patterns, sequencing strategies, access barriers, and real-world considerations influencing CAR T and BsAb use in RRMM using Likert-type scales and utilization metrics. Qualitative interviews followed a semi-structured guide exploring physician rationale for treatment selection, sequencing philosophies, and access-related decision-making. Results: Physicians consistently described relapse after CAR T or BsAbs as one of the most challenging aspects of RRMM management. While 56% preferred sequencing CAR T prior to BsAbs, real-world constraints often led to bispecific therapy being used first due to off-the-shelf availability. After progression, 67% reported no clear standard of care, relying on individualized decisions informed by prior response depth and durability, toxicity, performance status, and treatment availability. Re-treatment with an alternate T-cell–redirecting modality was commonly considered, though concerns regarding T-cell exhaustion, diminished efficacy, and cumulative toxicity were frequently cited. Some physicians favored non–T-cell–engaging regimens or clinical trial enrollment, particularly for frail or heavily pretreated patients. There was broad consensus that limited guidance and lack of strong efficacy data for post–T-cell–redirecting therapy represent a critical gap. Conclusions: As CAR T and BsAbs become foundational in RRMM, the lack of guidance for managing relapse after these therapies represents an emerging clinical gap. Physicians report heterogeneous, individualized approaches in the absence of a defined standard of care. Although CAR T remains preferred earlier in sequencing, real-world constraints frequently influence treatment order. These findings highlight the need for prospective studies and real-world evidence to clarify post–T-cell–redirecting therapy sequencing, inform clinical frameworks, support decision-making, and improve outcomes for patients with RRMM.
Hendry et al. (Thu,) studied this question.