A systematic review and meta-analysis has estimated the frequency of second primary malignant neoplasms (SPMs) occurring after treatment with T-cell-engaging bispecific antibodies across B-cell non-Hodgkin lymphoma and multiple myeloma. The analysis, published on PubMed, included 20 studies with 2,551 patients reporting SPM outcomes. Across 8 studies reporting total SPMs, the pooled estimate was 3.5% at a median follow-up of 17.4 months. Disease-specific estimates were 3.8% for NHL and 3.4% for MM. For clinically consequential endpoints, the pooled estimates were 2.2% for SPMs leading to treatment discontinuation and 1.4% for SPMs leading to death. The authors note that follow-up length and heterogeneity in reporting remain constraints, but the pooled results suggest SPMs are a measurable long-term complication as bispecifics move earlier in treatment regimens and broaden usage. Exploratory meta-regression did not identify study-level covariates associated with total SPM estimates.