IVIG supplementation reduces the frequency of serious infections in patients treated with teclistamab. (A) Serious (grade ≥ 3) infectious events per patient-year in patients treated with teclistamab according to treatment with IVIG (primary prophylaxis) or without IVIG (observation group). (B) Cumulative incidence plot of time to first serious infection in patients treated with teclistamab according to treatment with IVIG (primary prophylaxis) or without IVIG (observation group). IRR, incidence rate ratio.