Reducing Time Toxicity for Anti-B-Cell Maturation Antigen (BCMA) Bispecific Treatment: Evidence from Pivotal Single-Arm Trial Data on Teclistamab, Elranatamab, and Linvoseltamab for Triple-Class Exposed (TCE) Relapsed/Refractory Multiple Myeloma (RRMM)

Introduction: Oncologists increasingly recognize the need to evaluate the impact of cancer therapies on patients’ time, known as “treatment-related time toxicity”, which is measured as the number of days of contact with the healthcare system (Gupta A et al. J Clin Oncol 2022). Current standard-of-care options for patients with TCE RRMM require frequent clinic visits for treatment administration. Reducing treatment-related time toxicity of treatment without compromising efficacy or safety may have an impact on patients’ quality of life and influence treatment choice. BCMA-directed bispecific antibodies (BCMA bsAbs) provide a novel treatment option for TCE RRMM, with response-adapted dosing frequency allowing for extended dosing intervals for patients. The frequency of extended dosing intervals varies between BCMA bsAbs according to their prescribing information or pivotal trial protocol. The aim of this analysis was to evaluate the impact of BCMA bsAbs’ extended dosing intervals on treatment-related contact (TRC) days corresponding to treatment administration as a component of time toxicity.

Methods: An Excel-based longitudinal model was developed to quantify the number of TRC days experienced by patients with TCE RRMM within the healthcare system when receiving treatment with BCMA bsAbs (linvoseltamab, teclistamab, or elranatamab) over 1–2 years. TRC days included all planned treatment administration days. Model inputs were sourced from product labels or pivotal trial protocols for bsAbs, as well as the published literature.

To allow for a comparison of total dosing regimens, it was assumed that patients continued receiving treatment throughout the study period with no discontinuation. Dosing intervals for each product during the first 6 months were once weekly (QW), except for linvoseltamab (QW for Weeks 1–14, then once every 2 weeks [Q2W] from Weeks 16–24, per Phase 2 trial protocol). The extended dosing interval for linvoseltamab was Q4W for patients reaching very good partial response or better at or after 24 weeks, and Q2W for both teclistamab patients who maintained a complete response (CR) or better for ≥6 months and for elranatamab patients who reached partial response or better at or after 6 months. Two switching scenarios were considered for teclistamab: an earliest possible switch (at Week 26), and a time-varying switch based on digitized time to CR data from MajesTEC-1 (Usmani SZ et al. ASCO 2023).

Results were calculated to evaluate the difference in TRC days between the scenarios with and without extended dosing intervals for each treatment.

Results: In the first year of treatment, the total number of TRC days with and without extended dosing intervals was lowest with linvoseltamab. TRC days with linvoseltamab were reduced from 33 to 26 days with extended dosing intervals. Next lowest was elranatamab (53 to 39 days), followed by teclistamab (54 to 41 days for earliest possible switch and 54 to 50 days with time-varying switching).

Over 2 years, linvoseltamab had the lowest number of TRC days (59 to 39 days), followed by elranatamab (105 to 65 days) and teclistamab (106 to 67 days for earliest possible switch and 106 to 80 days with time-varying switching).

Conclusions: Extended dosing intervals with BCMA bsAbs can substantially reduce time toxicity for patients with RRMM. Linvoseltamab had the lowest number of TRC days among BCMA bsAbs.