The retrospective evaluation of efficacy and safety data after switching from originator rituximab to biosimilar rituximab (CT-P10) in patients diagnosed with systemic lupus erythematosus: a single-center experience.

OBJECTIVE:In our study, we analyzed the efficacy and safety data of patients with systemic lupus erythematosus (SLE) after switching to biosimilar rituximab (RTX). PATIENTS AND METHODS:Twenty-two patients who switched to RTX were included in the study. Efficacy data were analyzed using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, and safety data were analyzed using the frequency of side effects. RESULTS:The mean treatment duration of originator RTX was 35.6 ± 23.0 months, and the median treatment duration of biosimilar RTX was 17 months. The SLEDAI-2K score, approximately three months after the first dose of biosimilar RTX, was significantly lower (p = 0.027). A statistically significant difference was found between the SLEDAI-2K score assessed at the follow-up visit three months after the last dose of originator RTX and the SLEDAI-2K score obtained approximately three months after the first dose of biosimilar RTX (p = 0.011) and the calculated median SLEDAI-2K score was significantly lower than the SLEDAI-2K score assessed after administration of originator RTX. The side effect frequency that developed during the treatment of originator RTX was 15.3 per 100 patient-years. The most common side effect was infection, which was 15.3 per 100 patient-years. The most frequent infection was urinary tract infection. The side effect frequency during treatment of biosimilar RTX was 39 per 100 patient-years, and the most frequent infection was pneumonia. CONCLUSIONS:In our study, SLEDAI-2K scores demonstrated that no efficacy loss was experienced after switching to CT-P10 molecule, which is a biosimilar RTX. It was observed that switching to biosimilar RTX did not decrease treatment efficacy in the patient group diagnosed with SLE and biosimilar RTX was found to be safe.