Efficacy and safety of repeated low-dose rituximab therapy in relapsing-remitting multiple sclerosis: A retrospective case series study

Abstract

Background: Rituximab (RTX) is an extensively used off-label drug for multiple sclerosis (MS), whereas the induction and maintenance regimens vary widely among studies. Few data are available on efficacy and safety of repeated low-dose RTX therapy in MS patients.

Objective: This study aimed to evaluate the efficacy and safety of repeated low-dose RTX therapy for relapsing-remitting MS (RRMS), the most common form of MS affecting approximately 85% of patients.

Methods: Nine RRMS patients were enrolled and the medical records were retrospectively reviewed. RTX at 100 mg per week for three consecutive weeks was used as induction therapy. Maintenance therapy was reinfusions of RTX at 100 mg every 6 months during the first year, followed by 100 mg every 6 to 12 months. Main outcome measures included annualized relapse rate (ARR), expanded disability status scale (EDSS) score, and T2 lesion burden on MRI for evaluating the efficacy of low-dose RTX regimen. Meanwhile, adverse events (AEs) were recorded to assess the safety of repeated RTX infusions.

Results: All patients were females with an average onset age of 25.4 ± 6.7 years. The median disease duration before the first RTX infusion was 56 (range, 3-108) months and the median follow-up period was 30 (range, 15-40) months. No relapses were recorded in all patients after RTX therapy. Repeated low-dose RTX therapy resulted in a dramatic reduction of median ARR (pre-RTX vs post-RTX, 1.1 vs 0, p = 0.012), median EDSS score (2.0 vs 0, p = 0.007), and the number of T2 lesions on MRI (35.6 ± 18.0 vs 29.4 ± 18.1, p = 0.001). A total of 35 episodes of AEs occurred during repeated low-dose RTX therapy, and all of them were mild and transient.

Conclusion: Repeated low-dose RTX therapy is cost-effective for RRMS patients and shows a good safety profile. It may be a promising option for those having no access or poor response to first-line disease-modified drugs (DMDs), particularly in low- or middle-income countries.

Keywords: Efficacy; Multiple sclerosis; Relapsing-remitting MS; Rituximab; Safety.