Cytokine release syndrome (CRS) is the most common early complication of bispecific antibody therapy in multiple myeloma, occurring in an estimated 60–70% of patients, though severe (grade ≥3) CRS is rare. CRS typically presents with fever and, less frequently, hypotension or hypoxemia, generally emerging within 24–48 hours of a step-up or treatment dose. Grading and management follow a stepwise approach: grade 1 CRS is managed with fever control (dexamethasone or tocilizumab, depending on institutional access), while higher-grade CRS may require escalation to tocilizumab, additional corticosteroids, and, rarely, ICU-level care.

1 Prophylactic tocilizumab, administered before the first step-up dose, has emerged as an effective strategy to reduce CRS incidence and severity, leveraging its long half-life to cover the step-up dosing period without compromising efficacy. In one prophylaxis…