Background: Prognosis is poor for patients with R/R DLBCL, particularly those who are ineligible for autologous stem cell transplant (ASCT) or who relapse after second-line therapy (Gisselbrecht C, et al. Br J Haematol 2018). While chimeric antigen receptor therapies have shown favorable response rates in R/R DLBCL, convenient off-the-shelf options are needed, especially for patients with rapidly progressing disease (Sermer D, et al. Blood Adv 2020). Glofitamab is a full-length, humanized, immunoglobulin G1 bispecific antibody with two regions that bind to CD20 (B cells) and one region that binds to CD3 (T cells). In an ongoing Phase I study in patients with R/R non-Hodgkin lymphoma, glofitamab monotherapy has induced high response rates with a manageable safety profile (NCT03075696; Hutchings M, et al. ASH 2020). Rituximab in combination with gemcitabine and oxaliplatin (R-GemOx) is widely used for patients with R/R DLBCL who are not eligible for ASCT (Mounier N, et al. Haematologica 2013). Methods: GO41944 (NCT04408638) is a Phase III, open-label, randomized trial designed to evaluate the safety and efficacy of glofitamab plus gemcitabine and oxaliplatin (glofit-GemOx) vs R-GemOx in patients with R/R DLBCL. Eligible patients must be aged ≥ 18 years, have histologically confirmed DLBCL (excluding transformed indolent disease, and high-grade B-cell lymphoma (BCL) with MYC and BCL2 and/or BCL6 rearrangements), and have received ≥ 1 prior systemic therapies; patients who have failed only one prior line of therapy must not be eligible for high-dose chemotherapy followed by ASCT. Prior treatment with GemOx, R-GemOx or a CD20xCD3 bispecific antibody is not permitted. Patients are randomized 2:1 to receive up to eight 21-day cycles of either glofit-GemOx (intravenous [IV], followed by up to four cycles of glofitamab monotherapy) or R-GemOx (IV). A single dose of obinutuzumab is administered seven days prior to the first glofitamab administration. Randomization is stratified by number of prior lines of therapy and outcome of last systemic therapy (relapsed vs refractory). The primary objective is overall survival from time of randomization. Secondary efficacy objectives include progression-free survival, complete and overall response rates, duration of response, and time to deterioration in physical functioning and fatigue, and in lymphoma symptoms. Safety objectives comprise rate of adverse events, change from baseline in targeted vital signs and clinical laboratory test results, and tolerability. Pharmacokinetic, immunogenicity and biomarker endpoints will also be explored. The study started on February 17, 2021; an estimated enrollment of 270 patients by the study completion date of March 2022 is anticipated. Clinical trial information: NCT04408638