Real-world safety of rapid 30-minute intravenous isatuximab infusion in multiple myeloma: results from the largest published cohort.

Background: Isatuximab, an anti-CD38 monoclonal antibody, is a cornerstone therapy for multiple myeloma (MM). Standard intravenous infusion requires a minimum of 75 minutes per dose, representing a significant burden on patients and day-hospital resources. A rapid 30-minute infusion protocol has shown promise in early clinical trials, but large real-world datasets remain scarce. Methods: We conducted a descriptive, retrospective, multicenter study across 9 Spanish hospitals, including patients with confirmed MM who had received at least one rapid (30-minute) intravenous isatuximab infusion. Demographic, clinical, treatment, and safety data were collected. Infusion-related reactions (IRRs) were graded per CTCAE v5.0. Data cut-off: 1 May 2026. Results: A total of 103 patients were included (median age 66 years; 54.4% female). A total of 1,344 rapid 30-minute infusions were administered. Only 1 IRR was recorded: per-patient rate 0.97% (95% CI: 0.17%-5.30%), per-infusion rate 0.074% (95% CI: 0.013%-0.420%). Notably, 22 patients (21.4%) had experienced IRRs at standard rate; 21 of these (95.5%) completed the rapid protocol without reverting to standard rate. No patient permanently discontinued isatuximab due to an IRR. No treatment failure was attributable to the infusion rate change during the observation period. The protocol generated an estimated 1,008 hours of cumulative day-hospital chair time savings. Conclusion: Rapid 30-minute intravenous isatuximab demonstrates an excellent real-world safety profile, including in patients with prior IRRs, and generates clinically meaningful resource savings. To our knowledge, this is the largest published real-world cohort to date. These findings support its use as a feasible implementation strategy while prospective comparative studies remain warranted.