ObjectiveTo evaluate disease activity in patients with relapsing-remitting MS (RRMS) receiving rituximab with an extended dosing interval.MethodsIn the context of COVID-19 pandemic, this was an interim analysis of an ongoing prospective observational study of patients who were stable on rituximab for at least 6 months and who had a planned extended dosing interval of 24 months. Only data for patients with active RRMS before rituximab were analyzed.ResultsAmong 177 patients receiving rituximab, 33 had RRMS and MRI activity before rituximab and at least 8 months of follow-up after the last infusion. The mean (SD) age was 40 (14) years, 25 were females, the mean disease duration was 10 (6.8) years, the mean annual relapse rate (ARR) before rituximab was 1.7 (1.3), and the median Expanded Disability Status Scale (EDSS) score before rituximab was 4.5 (1–7). Before extended dosing, when rituximab was infused every 6 months, the mean (SD) ARR decreased to 0.04 (0.1) (p < 0.0001) and the EDSS score to 4 (0–7) (p = 0.04). At the time of this analysis, the median follow-up since the last infusion was 11 (8–31) months. No patient showed relapse or disability progression. In total, 30 patients had at least 1 MRI performed since the last infusion (median time between the last MRI and the last infusion 10 [8–31] months). No MRI showed activity. The CD19+ cell proportion was >1% for 10 of 25 patients at the last count (median time 8 [6–25] months).ConclusionsAn extended dosing interval for rituximab for patients with stable MS during the COVID-19 pandemic may be associated with a low risk of disease activity.

Background and ObjectivesTo determine the frequency of hypogammaglobulinemia and infections in patients with multiple sclerosis (PwMS) receiving rituximab (RTX).MethodsThis prospective observational study included all consecutive PwMS receiving RTX at the university hospital of Marseille, France, between 2015 and 2020. Patient visits occurred at least every 6 months.ResultsWe included 188 patients (151 with relapsing-remitting MS; the mean age was 43.4 years [SD 12.9], median disease duration 10 years [range 0–36], median Expanded Disability Status Scale 5 [range 0–8], median follow-up 3.5 years [range 1–5.8], and median number of RTX infusions 5 [range 1–9]). Overall, 317 symptomatic infections and 13 severe infections occurred in 133 of 188 (70.7%) and 11 of 188 (5.9%) patients, respectively. After 4 years, 24.4% of patients (95% CI 18.0–33.1) were free of any infection and 92.0% (95% CI 87.1–97.1) had not experienced a severe infection. At RTX onset, the immunoglobulin G (IgG) level was abnormal in 32 of 188 (17%) patients. After RTX, IgG level was <7, <6, <4 and <2 g/L for 83 (44%), 44 (23.4%), 8 (4.2%) and 1 (0.53%) patients, respectively. The risk of infection was associated with reduced IgG levels (multivariate Cox proportional hazards hazard ratio [HR] = 0.86, 95% CI 0.75–0.98, p = 0.03). The risk of reduced IgG level <6 g/L increased with age (HR = 1.36, 95% CI 1.05–1.75, p = 0.01).DiscussionIn PwMS receiving RTX, reduced IgG level was frequent and interacted with the risk of infection.