In a new study, fenebrutinib showed reduced risk of disability progression by 12 percent compared to Ocrevus as early as 24 weeks. Additional analysis presented potential benefit in upper limb function. According to Genentech, fenebrutinib has the potential to become first-in-class in multiple sclerosis, as an oral, brain-penetrant BTK inhibitor for primary progressive and relapsing MS.

The study’s primary endpoint included confirmed disability progression based on the Expanded Disability Status Scale for functional disability; the timed 25-foot walk for walking speed; and the nine-hole peg test for upper limb function. The strongest treatment effect was observed on the risk of worsening on the nine-hole peg test by 26 percent compared to Ocrevus.

Additionally, an analysis showed fenebrutinib was superior to Ocrevus on a composite endpoint including two of the three components of the study – Expanded Disability Status Scale and nine-hole peg test – with a 22 percent reduction in risk.

Adverse events commonly observed in the fenebrutinib group were comparable to Ocrevus: infections, nausea, and hemorrhage. Transient and reversible liver enzyme elevations were observed more often in the fenebrutinib group, and all cases resolved after study drug discontinuation. No Hy’s law cases (an indicator for potential severe liver injury) were observed. Serious adverse events were reported in 19.1 percent of patients receiving fenebrutinib (versus 18.9 percent on Ocrevus) and led to 4.3 percent withdrawing from treatment (versus 3 percent on Ocrevus). In the study there were 1.4 percent fatal cases in the fenebrutinib arm versus 0.2 percent in the Ocrevus arm, all of which were assessed as unrelated to the study treatment by the investigators and no pattern was observed in timing or cause. Epidemiological studies have shown fatality rates are higher in people living with MS compared to the general population.

The findings were reported at the Americas Committee for Treatment and Research in Multiple Sclerosis Forum 2026 in San Diego, Calif. 

This data follow Genentech’s announcement in November 2025 that the FENtrepid study and the first of two Phase III relapsing multiple sclerosis studies (FENhance 2) met their primary endpoints. Once the second RMS study (FENhance 1) has read out, which is expected in the first half of 2026, data from all Phase III fenebrutinib trials will be submitted to the appropriate regulatory authorities.