Real-world outcomes and toxicity profiles of bispecific antibodies: A nationwide multiyear study.

e23053 Background: The adoption of bispecific antibodies has transformed cancer therapeutics, but concerns regarding their toxicity profiles and clinical outcomes remain. This study examines patient demographics, hospitalization trends, and treatment-related complications in a nationally representative inpatient cohort from 2018–2021. Methods: Using the National Inpatient Sample, data from 61,890 patients receiving bispecific antibody treatments were analyzed. Outcomes included discharge patterns, length of stay, and mortality, along with complications such as neutropenia, thrombocytopenia, tumor lysis syndrome (TLS), and toxic encephalopathy. Statistical models identified predictors of adverse events, with subgroup analyses by demographics and comorbidities. Results: Neutropenia was the most common complication (peak 2,515 cases in 2021), with strong associations noted across all years (2019: OR: 13.84, 2021: OR: 14.32, p < 0.001). TLS cases increased significantly, reaching an OR of 58.58 in 2021 (p < 0.001). Anemia and thrombocytopenia remained prevalent but showed variable trends, while toxic encephalopathy peaked in 2020. Female gender and elective admissions were protective across complications, while older age, anemia, and CKD emerged as significant risk factors. The South represented the largest regional population (35%), and most admissions occurred in urban teaching hospitals (95%). Conclusions: Bispecific antibody therapies are associated with substantial hematologic and systemic toxicities, requiring tailored management strategies. Increased risk in older patients and those with preexisting conditions highlights the need for personalized care. These findings inform future research and clinical guidelines to optimize safety and efficacy in bispecific antibody treatments.