The Effectiveness of Medications in Treating Primary Progressive Multiple Sclerosis

Primary progressive multiple sclerosis (MS) is a debilitating disease characterized by a steady decline in symptoms as the body’s immune system attacks the protective myelin around nerves. A recent study published in the September 25, 2024, online issue of Neurology^® has found that certain medications may not slow disability progression in people with this type of MS.

The study focused on rituximab and ocrelizumab, which are anti-CD20 infusion therapies that target a protein called CD20 found on B-cells in the bloodstream. These medications are believed to reduce inflammation and damage to myelin, potentially slowing the progression of disability in MS patients. While ocrelizumab is approved by the FDA for primary progressive MS, rituximab is not and is typically prescribed off-label for this condition.

Lead researcher Laure Michel, MD, PhD, from Rennes University in France, emphasized the need for treatments that can effectively slow disability progression in people with primary progressive MS. The study involved 1,184 participants with an average age of 56 who had not taken any MS medications for two years prior to the study. They were divided into groups receiving rituximab, ocrelizumab, or no treatment, and were monitored for an average of four years.

Disability progression was assessed using a standardized scale, with participants starting at a score of 6.5 or less. Researchers measured the time it took for participants to reach the next level of disability, adjusting for any differences between the treated and untreated groups. Surprisingly, the study found that there was no significant difference in disability progression between those taking medications and those receiving no treatment.

Michel highlighted the importance of continuously evaluating MS therapies to determine their efficacy and potential risks for individuals with primary progressive MS. The study, while informative, had limitations, including its retrospective design and the unequal distribution of participants taking rituximab versus ocrelizumab. Further research involving larger cohorts is needed to validate these findings.

Despite these limitations, the study sheds light on the challenges of treating primary progressive MS and the ongoing quest for more effective therapies. The research was supported by various organizations, including the France National Research Agency and the Eugène Devic EDMUS Foundation.