Fenebrutinib: Efficacy and Safety Flags

Multiple sclerosis is a disease in which the immune system attacks the brain and spinal cord, leaving scars that can trigger relapses and lasting disability. Roche said on April 21 that its experimental pill fenebrutinib cut relapses more than teriflunomide in two Phase III studies of relapsing multiple sclerosis. (roche.com) In the FENhance 1 trial, fenebrutinib reduced the annualized relapse rate by 51.1% versus teriflunomide over 96 weeks. In FENhance 2, the reduction was 58.5%, according to Roche’s late-breaking presentation at the 2026 American Academy of Neurology meeting in Chicago. (roche.com) Fenebrutinib is a Bruton’s tyrosine kinase inhibitor, a drug designed to interrupt immune-cell signaling rather than wipe out whole B-cell populations. Roche said the drug also reduced new brain lesions and showed positive trends on disability progression, though those progression results were not the primary endpoint. (roche.com) The safety picture is more complicated than the efficacy result. STAT reported on April 21 that trial data disclosed two drug-related deaths among patients who took fenebrutinib, alongside liver-safety questions that analysts were already watching. (statnews.com) Reuters reported on April 22 that Roche was submitting fenebrutinib to global regulators even as data released that day showed seven patients died during the relapsing-multiple-sclerosis studies. Roche told Reuters it believed the overall benefit-risk profile supported filing. (wdez.com) Fierce Biotech reported that Roche attributed the relapsing-multiple-sclerosis deaths to infections, diabetes complications and an accident, producing an imbalance between the fenebrutinib and control groups. The same report said serious adverse events were similar in FENhance 1 but wider apart in FENhance 2. (fiercebiotech.com) Those questions land in a field that has been waiting for an oral Bruton’s tyrosine kinase inhibitor after several rivals ran into safety or efficacy problems. Roche said fenebrutinib could become the first drug in that class approved for both relapsing and primary progressive multiple sclerosis if regulators accept the company’s data package. (roche.com) The primary progressive program is part of that package too. Roche has previously said its FENtrepid Phase III study compared fenebrutinib with Ocrevus, the only approved therapy for primary progressive multiple sclerosis, and that all three pivotal studies would be submitted together to regulators. (assets.roche.com) Regulators now have to weigh a drug that beat an active comparator on relapses against a safety record that includes death imbalances and liver monitoring questions. That review, and any approval talks that follow, will turn on whether agencies decide the benefit is large enough to manage the risks in real-world use. (statnews.com)