Genentech announced the first of two pivotal, similarly-designed Phase III studies in patients with relapsing multiple sclerosis met its primary endpoint. Fenebrutinib, an investigational Bruton’s tyrosine kinase inhibitor, significantly reduced the annualized relapse rate compared to teriflunomide over a period of at least 96 weeks of treatment. 

Additionally, the phase III FENtrepid pivotal study evaluating fenebrutinib, compared with Ocrevus (ocrelizumab) in patients with primary progressive MS, also met its primary endpoint. The results showed that fenebrutinib was as effective as ocrelizumab, the only approved therapy in PPMS, as measured by a delay in the onset of composite confirmed disability progression during a period of at least 120 weeks of treatment. A numerical benefit for fenebrutinib compared to ocrelizumab was seen as early as week 24, and lasted throughout the observation period.

Liver safety was consistent with previous fenebrutinib studies. Additional safety data is being further evaluated. The results of the second RMS phase III trial are expected by the first half of 2026.

Fenebrutinib targets cells in the immune system known as B cells and microglia. Targeting B cells helps control the acute inflammation that causes relapses, while targeting microglia inside the brain addresses the chronic damage that is thought to drive long-term disability progression. Fenebrutinib, a noncovalent BTKi, is designed to have high potency, selectivity, and reversibility. This design allows it to act throughout the body, and also to cross the blood-brain barrier into the central nervous system targeting chronic inflammation.

Full data from both studies will be shared at upcoming medical meetings; once the second RMS study (FENhance 1) has read out, which is expected in the first half of 2026, all data together will be considered for submission to regulatory authorities.