Objective To investigate the clinical utilization of Rituximab biosimilar (Rituximab injection) in order to provide references for evaluating its rationality and economic value in clinical application.

Methods A retrospective analysis was conducted on medical records of inpatients who received Rituximab injection at Peking Union Medical College Hospital between January 1, 2020, and December 31, 2023. The clinical usage patterns, off-label use, economic benefits compared to the originator drug, and adverse drug reactions (ADRs) were analyzed.

Results A total of 725 patients treated with Rituximab injection were included. The majority of patients were from the Department of Nephrology (80.69%), followed by Rheumatology and Immunology (9.24%), Hematology (8.41%), and Dermatology (0.97%). The drug was used for 27 different diseases, with the top five being membranous nephropathy (62.90%), minimal change disease (7.31%), systemic lupus erythematosus (4.41%), anti-neutrophil cytoplasmic antibody-associated vasculitis (3.72%), and granulomatosis with polyangiitis or microscopic polyangiitis (3.59%). The off-label use rate was as high as 96.28% (698/725). The overall incidence of ADRs was 21.24%. The total consumption of Rituximab injection was 1183.2 g, resulting in calculated cost savings of about ￥7.35 million compared to the originator drug.

Conclusions Rituximab injection is widely used in hematologic malignancies and immune-mediated diseases, with a low overall incidence of ADRs and greater cost-effectiveness compared to the originator drug. The extremely high rate of off-label use is supported by corresponding guidelines or clinical studies.