Roche's MS Tablet Fenebrutinib Shows Promise in Late-Stage Trials

Roche's experimental multiple sclerosis (MS) drug fenebrutinib has demonstrated positive results in two late-stage clinical trials, potentially paving the way for a new oral treatment option for both relapsing and primary progressive forms of the disease.

Fenebrutinib Succeeds in Relapsing MS Trial

In a Phase 3 trial focusing on relapsing MS, fenebrutinib significantly reduced the average number of relapses experienced by patients compared to Sanofi's Aubagio. This marks a crucial milestone for the drug, as relapsing MS is the most common form of the disease. A second, similarly designed experiment is expected to produce results in the first half of 2026, which could further solidify fenebrutinib's efficacy profile.

Primary Progressive MS Trial Shows Non-Inferiority to Ocrevus

Notably, fenebrutinib also succeeded in a separate study involving nearly 1,000 people with primary progressive MS. The drug demonstrated non-inferiority to Roche's own blockbuster product, Ocrevus, in slowing disease progression. This study, which followed participants for at least 120 weeks, used a composite measure of walking speed, arm function, and overall disability level to evaluate disease advancement.

Unique Mechanism of Action and Potential Impact

Fenebrutinib stands out as the first potential oral therapy targeting Bruton's tyrosine kinase (BTK) for MS treatment. BTK inhibitors have shown success in treating blood cancers and certain autoimmune conditions, but their application in MS has faced challenges. The drug's mechanism of action involves inhibiting the development of B cells, which are believed to play a role in the autoimmune attack on the myelin sheath surrounding nerve fibers in MS patients.

Dr. Levi Garraway, Roche's chief medical officer, expressed optimism about the trial outcomes, stating, "These unprecedented results suggest that fenebrutinib could potentially become a best-in-disease medicine as the first high-efficacy, oral treatment" for people with relapsing or primary progressive MS.

Challenges and Considerations

Despite the positive results, fenebrutinib faces several hurdles. The FDA has previously issued partial clinical holds on various BTK inhibitors, including fenebrutinib, due to safety concerns, particularly regarding liver injury. Additionally, analysts question whether showing non-inferiority to Ocrevus is sufficient for approval in primary progressive MS, and whether Roche's filing strategy for relapsing MS will depend on the outcomes of the second ongoing trial.

As the pharmaceutical industry watches closely, fenebrutinib's development represents a potential shift in MS treatment paradigms, offering hope for an effective oral therapy that could address both relapsing and primary progressive forms of the disease.