Abstract: One trial involving 104 adult RRMS patients with an entry score ≤ 5.0 on the Expanded Disability Status Scale (EDSS) and at least one relapse during the preceding year was included. This trial evaluated rituximab as monotherapy versus placebo, with a single course of 1000 mg intravenous rituximab (on day 1 and day 15). A significant attrition bias was found at week 48 (24.0%). Patients receiving rituximab had a significant reduction in total number of gadolinium-enhancing lesions at week 24 (mean number 0.5 versus 5.5; relative reduction 91%) and in annualised rate of relapse at week 24 (0.37 versus 0.84) but not at week 48 (0.37 versus 0.72). Disability progression was not included as an outcome in this trial. More patients in the rituximab group had adverse events within the 24 hours after the first infusion (78.3% versus 40.0%), such as chills, headache, nausea, pyrexia, pruritus, fatigue, throat irritation, pharyngolaryngeal pain, and most were mild-to-moderate events (92.6%). The most common infection-associated adverse events (> 10% in the rituximab group) were nasopharyngitis, upper respiratory tract infections, urinary tract infections and sinusitis. Among them, only urinary tract infections (14.5% versus 8.6%) and sinusitis (13.0% versus 8.6%) were more common in the rituximab group. One ongoing trial was identified. There is not sufficient evidence to support the use of rituximab as a disease-modifying therapy for RRMS because only one RCT was included. The quality of the study was limited due to high attrition bias, the small number of participants, and short follow-up. The beneficial effects of rituximab for RRMS remain inconclusive. However, short-term treatment with a single course of rituximab was safe for most patients with RRMS. Mild-to-moderate infusion-associated adverse events were common, as well as nasopharyngitis, upper respiratory tract infections, urinary tract infections and sinusitis. The potential benefits of rituximab for treating RRMS need to be evaluated in large-scale studies that are of high quality along with long-term safety.

Plain-language summary: Recent studies showed that a class of white blood cells (B lymphocytes) can be involved in the pathology of MS. This feature has led to a renewed interest in therapies directed at controlling B-cell activity. Rituximab belongs to the class of monoclonal antibodies and is able to diminish the number of B lymphocytes in the cerebrospinal fluid. The authors of this review assessed the efficacy and safety of rituximab in patients with RRMS, taking into account relapses, brain lesions and disease progression. From the pertinent literature, only one study evaluating rituximab versus placebo in 104 adult patients with at least one relapse during the preceding year was included. The authors did not find convincing evidence to support rituximab as an effective treatment for RRMS, also because the quality of the one identified study was limited due to high attrition bias, the small number of participants, and short follow-up. As far as safety is concerned, patients reported infusion-associated adverse events within the 24 hours after the first infusion, including chills, headache, nausea, pyrexia, pruritus, fatigue, throat irritation and pharyngolaryngeal pain. Among infection-associated adverse events, only urinary tract infections (in 14.5% versus 8.6%) and sinusitis (13.0% versus 8.6%) were more common in the rituximab group. The potential benefits of rituximab for treating RRMS need to be further evaluated in large-scale studies that are of high quality along with long-term safety.