Sanofi terminates phase 3 trial of riliprubart in rare nerve disorder

Sanofi terminated a late-stage study of riliprubart in chronic inflammatory demyelinating polyneuropathy after an interim analysis showed the drug was unlikely to deliver sufficient efficacy, an early setback for new Chief Executive Belen Garijo.

The MOBILIZE phase 3 trial enrolled patients with CIDP refractory to standard-of-care treatment, the Paris-based drugmaker said Wednesday. An independent data monitoring committee determined the study was unlikely to meet its efficacy goals. No safety signals were identified.

Riliprubart (SAR445088, BIVV020) is an IgG4 humanized monoclonal antibody that inhibits activated C1s in the classical complement pathway, blocking inflammatory mechanisms that drive demyelination and axonal damage in CIDP. The drug had been considered a potential pipeline asset in Sanofi's immunology portfolio.

CIDP is a rare neurological condition affecting the peripheral nervous system, where the immune system attacks the myelin sheaths around nerve cells, causing progressive weakness and sensory impairment. About 30 percent of patients do not respond to standard therapies, and among those who do, roughly 70 percent have an incomplete response. Fewer than one-third of patients remain in remission without continued therapy.

Sanofi said it would evaluate whether to continue other ongoing studies with riliprubart, including the VITALIZE phase 3 trial in IVIg-treated CIDP patients. The company will work with investigators to wind down the MOBILIZE study and transition patient care.

The termination will not incur any significant financial cost, Sanofi said, and the company maintained its 2026 financial guidance.

The setback comes a month after Garijo assumed the chief executive role in May 2026. Sanofi separately advanced its pipeline in immunology this week, with partner Kymera Therapeutics announcing the first patient dosed in a phase 1 trial of KT-485 (SAR447971), an oral IRAK4 degrader for hidradenitis suppurativa, triggering a $20 million milestone payment to Kymera.

The MOBILIZE failure removes a potential late-stage candidate from Sanofi's immunology pipeline. Investors will watch for the company's decision on the VITALIZE study and for further pipeline updates under Garijo's leadership.

This article is for informational purposes only and does not constitute investment advice.