Roche has announced positive results from its phase III FENhance 1 and 2 studies evaluating fenebrutinib, an investigational oral Bruton’s tyrosine kinase (BTK) inhibitor, in patients with Relapsing Multiple Sclerosis (RMS). The studies met their primary endpoints, demonstrating a significant reduction in annualised relapse rates (ARR) compared to teriflunomide over a 96-week period.

Fenebrutinib reduced relapse rates by 51.1 percent in FENhance 1 and 58.5 percent in FENhance 2, translating to approximately one relapse every 17 years for treated patients—more than double the relapse-free duration seen with the comparator therapy. The findings were presented at the American Academy of Neurology Annual Meeting 2026.

The therapy also showed significant reductions in disease activity in the brain. MRI results indicated a reduction in inflammatory markers by over 70 percent and a decrease in chronic disease burden by up to 82.5 percent compared to teriflunomide. Positive trends were also observed in slowing disability progression, with notable improvements in overall and upper-limb function.

Safety outcomes were broadly consistent with existing therapies, with comparable rates of liver enzyme elevations and infections between treatment groups. Serious adverse events were similar across both arms, although a higher number of fatalities was reported in the fenebrutinib group, attributed to varied causes.

The results build on earlier findings from the phase III FENtrepid study in primary progressive multiple sclerosis, where fenebrutinib demonstrated non-inferiority to standard treatment. Collectively, these studies support the drug’s potential to address both relapsing and progressive forms of the disease.

Fenebrutinib is designed to target both peripheral immune activity and chronic inflammation within the central nervous system by inhibiting B cells and microglia. This dual mechanism may offer a differentiated approach in managing multiple sclerosis, a chronic neurological condition affecting over 2.9 million people globally.

Roche plans to submit the full dataset from its phase III programme to regulatory authorities, as it advances efforts to develop more effective treatments for multiple sclerosis and other neurological disorders.