Effectiveness and Tolerability of Nonmedical Switching from Originator (MabThera) to Biosimilar (Truxima) Rituximab in People with Multiple Sclerosis: A Tertiary Single-Center Observational Study

The study examined the safety and efficacy of switching patients with multiple sclerosis from originator rituximab (MabThera) to biosimilar (Truxima). Fifty patients were included in the observational study and followed for two years after the switch. The annualized relapse rate decreased from 0.45 before rituximab treatment to 0.02 with the originator product and 0.00 with the biosimilar. In imaging analysis, the proportion of active scans progressively decreased (50.0%, 34.5%, 17.2%). No significant differences in efficacy or tolerability were found between the originator product and biosimilar. All patients continued biosimilar treatment through the end of follow-up. The results support the use of rituximab biosimilar in patients with multiple sclerosis without concerns about reduced efficacy.