Real world safety outcomes of an outpatient lymphoma bispecific antibody program: A single center experience from Johns Hopkins.

e19018 Background: Bispecific Antibodies (BsAb) have demonstrated efficacy in the treatment of patients with hematologic malignancies through leveraging of T cell activity in targeting of malignant cells. Despite lacking the curative potential of CAR-T, limited toxicities and off the shelf availability make BsAbs a compelling treatment option for lymphoma. At the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center (JHSKCCC) a unique inpatient/outpatient program (IPOP) is a hybrid nursing unit that allows for deployment of intensive therapies in an outpatient setting nested in the hospital. This outpatient clinic is located adjacent to the hospital ward, allowing for daily appointments-ranging from 15 minutes to 12 hours-7 days a week. Patients are required to reside within a one-hour drive and have a 24-hour caregiver during ramp up dosing days. This infrastructure is bolstered by an adjacent oncology urgent care center, where supportive therapies for cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) can be initiated outside of IPOP hours. Methods: In this retrospective electronic medical record (EMR) analysis of 28 patients at the JHSKCCC IPOP treated with the CD20/CD3 BsA therapies epcoritimab or mosunetuzumab from 1/2023 to 11/2024, safety outcomes including CRS and ICANS incidence and management are analyzed. Results: A total of 6 patients were treated with mosunetuzumab, of whom 2 developed grade 1 CRS. Both cases presented with fever within 24 hours after D15 dosing, and both resolved with supportive care. There were no cases of ICANS in this population. A total of 22 patients were treated with epcoritamab, of whom 6 developed grade 1 CRS, 6 developed grade 2 CRS, and 1 developed grade 4 CRS (vs. acute respiratory distress syndrome [ARDS] ). Among these patients, 5/6 of grade 1 cases, 5/6 of grade 2 cases, and 1/1 of grade 4 cases occurred following D15 dosing. In patients who developed grade 1 CRS, median onset was D17, and all cases were treated with supportive care only. In patients who developed grade 2 CRS: 1 received tocilizumab alone, 2 received tocilizumab plus dexamethasone, 1 received dexamethasone alone, and 2 were treated at outside hospitals with limited records. In the singular patient with grade 4 CRS, he was admitted to an outside hospital with grade 4 CRS vs ARDS from COVID-19 infection on D41. Conclusions: Review of IPOP patient safety data resulted in the following initiatives targeting common sites of workflow breakdown: 1) Standardized BsAb toxicity management algorithms, 2) A BsAb toxicity management order set in the EMR including a PRN Tocilizumab dose, and 3) patient education resources for toxicity recognition after D15. Through optimal education of patients and providers paired with bolstered EMR support during transitional care, we hope to maximize patient quality of life and access to efficacious care.