For patients with multiple myeloma who have exhausted standard treatment options, the immunotherapy landscape is undergoing a fundamental shift — one that moves beyond a single molecular target and toward multi-antigen strategies designed to outmaneuver tumor resistance. This evolution carries real implications for how oncologists sequence therapies and how long patients may sustain remission.
A narrative review synthesizing data from the 2025 Immune Cell Effector Therapies (ICE-T) Symposium examined the growing arsenal of bispecific T-cell engagers (BiTEs) and CAR-T constructs in relapsed/refractory multiple myeloma (RRMM) and related hematologic malignancies. BCMA-directed bispecific antibodies teclistamab and elranatamab achieved overall response rates of approximately 63% and 61%, respectively, in heavily pretreated patient populations, with median progression-free survival ranging from roughly 11 to 17 months. Critically, the review highlights expansion to novel targets — GPRC5D and FcRH5 — alongside multitarget constructs engineered to reduce antigen escape, a primary mechanism of treatment failure with single-target approaches.
The significance here is structural, not merely incremental. BCMA has been the dominant immunological address in myeloma for several years, but single-target dependency creates a predictable vulnerability: tumor cells that downregulate or lose BCMA expression can evade immune clearance entirely. The pivot to GPRC5D and FcRH5, both expressed on myeloma cells with different regulatory profiles, offers an orthogonal attack vector. Multi-target bispecifics or sequential CAR-T strategies may delay or prevent this escape. However, several limitations temper enthusiasm: this is a conference-based narrative review rather than an independent meta-analysis, real-world outcomes often trail clinical trial benchmarks, and durability data beyond 18 months remains sparse. Toxicity profiles — particularly cytokine release syndrome and infections in immunocompromised patients — remain clinically consequential. The field is advancing rapidly, but head-to-head comparative trials are still lacking, leaving sequencing decisions largely empirical.