Real-world incidence of severe infections in multiple myeloma patients receiving bispecific antibodies: a meta-analysis.

Bispecific antibodies (BiTEs) have transformed the therapeutic landscape of relapsed/refractory multiple myeloma (RRMM), offering deep and durable responses even in heavily pretreated patients. However, their use carries substantial infectious risk due to immunosuppression, particularly hypogammaglobulinemia, induced by T-cell-redirecting therapy. To define the real-world incidence of grade 3–4 infections, we conducted a systematic review and meta-analysis of retrospective studies including RRMM patients treated with BiTEs currently approved for clinical use. Ten studies encompassing 1,373 patients were analysed using a random-effects model of pooled proportions. The overall rate of grade 3–4 infections was 0.25 (95% CI, 0.22–0.30) after a median follow-up of 8.3 months, with moderate heterogeneity (I²=52.9%). Subgroup analyses showed comparable pooled event rates for teclistamab—anti-CD3/BCMA—(0.26; 95% CI, 0.22–0.31) and talquetamab—anti-CD3/GPRC5D—(0.23; 95% CI, 0.14–0.33). Meta-regression revealed an inverse association between infection rates and mean number of prior therapy lines (p = 0.002) and prior BCMA exposure (p = 0.0019), likely because, in real world setting, clinicians select fitter, immunologically stable patients for BiTEs therapy. In summary, approximately one in four RRMM patients receiving BiTEs experiences severe infection. These findings underscore the need for proactive monitoring and standardized preventive measures, including immunoglobulin replacement, prophylaxis, vaccination, to ensure safe, effective integration of BiTEs into routine MM care.