A systematic review and meta-analysis published on PubMed finds that second primary malignant neoplasms (SPMs) occur measurably after T-cell-engaging bispecific antibody therapy used in adult NHL and multiple myeloma. The analysis pooled SPM estimates across 20 studies covering 2,551 patients, using a protocol registered in PROSPERO. Across available follow-up (median 17.4 months), the pooled estimated proportion of total SPMs was 3.5% (95% CI, 1.8–6.9). Disease-specific estimates were 3.8% for NHL and 3.4% for multiple myeloma. The pooled estimate for SPMs leading to treatment discontinuation was 2.2%, and SPMs leading to death were 1.4%. The authors report that exploratory meta-regression did not identify study-level variables associated with total SPM incidence, while emphasizing that relatively short follow-up limits definitive long-term conclusions.