An international multicenter study comparing COVID‐19 omicron outcomes in patients with hematological malignancies treated with obinutuzumab versus rituximab

Objectives Hematological malignancy (HM) patients treated with anti‐CD20 monoclonal antibodies are at higher risk for severe COVID‐19. A previous single‐center study showed worse outcomes in patients treated with obinutuzumab compared to rituximab. We examined this hypothesis in a large international multicenter cohort. Methods We included HM patients from 15 centers, from five countries treated with anti‐CD20, comparing those treated with obinutuzumab (O‐G) to rituximab (R‐G) between December 2021 and June 2022, when Omicron lineage was dominant. Results We collected data on 1048 patients. Within the R‐G (n = 762, 73%), 191 (25%) contracted COVID‐19 compared to 103 (36%) in the O‐G. COVID‐19 patients in the O‐G were younger (61 ± 11.7 vs. 64 ± 14.5, p = 0.039), had more indolent HM diagnosis (aggressive lymphoma: 3.9% vs. 67.0%, p