Single-Agent Mosunetuzumab Is A Promising Safe And Efficacious Chemotherapy-Free Regimen For Elderly/Unfit Patients With Previously Untreated Diffuse Large B-Cell Lymphoma

Introduction: Up to 30% of patients (pts) aged ≥75 years do not receive standard chemoimmunotherapy (CIT) as first-line (1L) treatment for diffuse large B-cell lymphoma (DLBCL) due to concerns about frailty and comorbidities. Poor outcomes are commonly reported for elderly/unfit pts with 1L DLBCL who receive no treatment, reduced-dose R-CHOP or other therapies such as R-CVP and R-bendamustine (Morrison, et al. J Geriatr Oncol 2020); less toxic, efficacious alternatives to full-dose CIT are needed. Mosunetuzumab (Mosun) is a full-length, fully humanized IgG1 CD20/CD3 bispecific antibody that redirects T cells to engage and eliminate malignant B cells. Single-agent Mosun has shown promising efficacy (including durable complete responses [CRs]) and tolerable safety in relapsed/refractory DLBCL pts in an ongoing Phase I study (GO29781; NCT02500407; Bartlett, et al. ASCO 2019, Schuster, et al. ASH 2019). Here we present early clinical data with Mosun as 1L therapy for elderly/unfit pts with DLBCL.