In the Cartitude 1 trial, the strongest predictor of long-term remission with Siltacel was a lower burden of disease (measured by bone marrow percentage and soluble BCMA levels), rather than the number of prior treatments. This implies using CAR-T therapy earlier in the disease course is more effective.

In a crowded multiple myeloma market, treatment sequencing is critical. The International Myeloma Working Group (IMWG) recommends using BCMA CAR-T therapies like Carvykti before BCMA bispecifics. This guidance helps defend Carvykti's position, as prior bispecific use may reduce CAR-T efficacy.

As frontline therapies improve and create longer remissions, the first relapse becomes the pivotal moment for treatment. Experts advocate for treating this stage with the same intensity and goals as newly diagnosed disease, including aiming for MRD negativity.

Data from the MAJESTIC three trial shows bispecific antibodies achieving progression-free survival rates comparable to CAR-T therapy. This creates a new clinical dilemma, forcing a choice between an immediate, off-the-shelf option for rapid progression versus a one-time therapy with a longer track record, making treatment an individualized decision.

With highly effective treatments like CAR-T and bispecifics moving into earlier lines of therapy for multiple myeloma, the clinical focus must evolve. While efficacy benchmarks have been met, the next advancement requires vigilant attention to safety, particularly infection risks and other side effects of new paradigms.

Using a BCMA bispecific antibody first can exhaust a patient's T-cells or cause tumors to lose the BCMA target, rendering a subsequent BCMA-targeted CAR-T therapy ineffective. The optimal sequence is CAR-T first, which preserves T-cell function and BCMA expression, leaving bispecifics as a viable later-line option.

In a heavily pretreated population, mezigdemide plus dexamethasone achieved a 50% response rate in patients refractory to prior BCMA-based approaches, including antibody-drug conjugates, bispecifics, and CAR T-cell therapy. This demonstrates a distinct mechanism that can overcome resistance to the latest immunotherapies.

Five-year follow-up from the CARTITUDE-1 trial suggests a potential cure for multiple myeloma is achievable. With roughly one-third of heavily pretreated patients remaining in remission at five years—and some confirmed as MRD-negative—the concept of a cure is now part of the operational discussion among specialists, a monumental shift for a disease long considered incurable.

CARTITUDE-IV trial data challenges the idea of reserving CAR-T therapy for high-risk myeloma. In early relapse, standard-risk patients treated with siltacel had a longer progression-free survival than even high-risk patients on the same therapy. This suggests standard-risk patients may gain the most relative benefit from earlier CAR-T intervention compared to standard of care.