[Balancing efficacy and cost in multiple myeloma immunotherapy: rethinking treatment strategies from a sustainability...

The prognosis of multiple myeloma (MM) has improved dramatically over the past two decades with the introduction of proteasome inhibitors, immunomodulatory drugs, anti-CD38 monoclonal antibodies, and, more recently, immune-based therapies such as chimeric antigen receptor (CAR) T-cell therapy and bispecific antibodies. Quadruplet regimens are now used in the frontline setting, enabling deeper responses and long-term survival, and even making functional cure a realistic goal for some patients. Nevertheless, MM remains a relapsing disease, and outcomes of triple-class-exposed (TCE) patients are still poor. While novel immunotherapies have significantly improved outcomes in relapsed or refractory MM, their extremely high costs may threaten the sustainability of healthcare systems, particularly in countries with universal health coverage, such as Japan. Cost-effectiveness analysis (CEA) using quality-adjusted life years (QALYs) provides a quantitative framework to evaluate the value of high-cost therapies. In this review, we summarize recent advances in immunotherapy for MM and discuss the cost-effectiveness of these therapies based on clinical trials, real-world data, and modeling studies. We also present our own analyses of daratumumab-based quadruplet induction and anti-BCMA CAR-T therapy. Finally, we discuss future strategies to balance innovation and sustainability, including patient selection, subgroup-based treatment optimization, and minimal residual disease-guided treatment discontinuation.