Among patients with multiple sclerosis (MS), low doses of rituximab (RTX) appear to have similar effectiveness compared with high doses of RTX, but have a better safety profile, according to new findings presented at MSVirtual2020.

An anti-CD20 monoclonal antibody, RTX is commonly used as an off-label treatment for MS, the authors of the study wrote. However, the regimen for RTX has yet to be standardized, despite existing safety and efficacy data.

This prompted the authors to perform a 2-center ambispective study of 303 patients with MS who had been treated with at least 1 RTX treatment cycle through February 2020. The centers were located in Barcelona, Spain (BC; n = 249) and Girona, Spain (GC; n = 54).

BC patients with MS were administered a dose of 2 g RTX intravenously for at least 3 cycles, followed by a dose of 1 g RTX every 6 months. GC patients with MS were treated with a dose of 2 g RTX intravenously for least the first cycle, followed by a dose of 500 mg RTX every 6 months.

Follow-up occurred every 6 months and consisted of laboratory tests. In addition, patients underwent brain magnetic resonance imaging (MRI) scans at baseline and once a year afterwards. The authors documented demographic, clinical, and radiological characteristics at baseline. Other data that were collected included:

• Annual relapse rate (ARR) at years 1 and 3 on RTX
• Contrast-enhancing lesions (CELs) at years 1 and 3 on RTX
• New T2 lesions at years 1 and 3 on RTX
• Expanded Disability Status Scale (EDSS) changes at the most recent follow-up visit
• Dynamics of serum Cluster of Differentiation 19 (CD19) lymphocytes and immunoglobulin G (IgG) values
• Adverse events

Approximately 45.8% of BC patients and 79.6% of GC patients had opted to initiate RTX due to clinical progression, along with inflammatory activity measured clinically, radiologically, or both. Mean ARRs at baseline were 0.37 and 0.33 for BC and GC patients, respectively. Median EDSS scores were 5.5 and 6.0 for BC and GC patients, respectively. The proportions of MRIs with CELs were 32.4% and 42.6% for BC and GC patients, respectively.

The results of the study indicated that ARRs were 0.05 among BC patients and 0.03 among GC patients at year 1, and 0.08 among BC patients and 0 among GC patients at year 3. Among patients with progressive phenotypes, approximately 79.4% of BC patients and 71.4% of GC patients either remained stable or experienced improvements in EDSS scores.

Approximately 2.7% of BC patients and 8% of GC patients had new CELs at year 1. Corresponding values at year 3 were 0% for both groups. Approximately 19% of BC patients and 16% of GC patients had new T2 lesions at year 1. Corresponding values at year 3 were 12% and 0%, respectively.

The authors observed no differences in the dynamics of CD19 lymphocytes. During the first 3 years, IgG values had decreased significantly among BC patients. In addition, BC patients (14.8%) demonstrated a higher incidence of adverse events than GC patients (4.1%) during year 1.

—Christina Vogt

Reference:
Midaglia L, Alvarez Bravo G, Robles Cedeño R, et al. PS01.05 - Rituximab treatment for MS: an observational multicentric dose comparison. Paper presented at: ACTRIMS/ECTRIMS MSVirtual2020; September 11-13, 2020.