Sanofi has stopped the Phase 3 MOBILIZE trial of riliprubart in refractory CIDP after an interim analysis found the study unlikely to demonstrate sufficient efficacy. No new safety concerns were identified.
Written By: Shaik Yasmeen, PharmD
Reviewed By: Pharmacally Editorial Team
Sanofi has discontinued the Phase 3 MOBILIZE trial evaluating riliprubart in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) who failed to respond adequately to standard therapies. The decision follows a planned interim analysis by an independent data monitoring committee, which concluded that the study was unlikely to achieve sufficient efficacy. No safety signals related to riliprubart were identified during the review.
The MOBILIZE study (NCT06290128) represented a key component of Sanofi’s late-stage neurology pipeline. The company said it will now assess the implications of the findings for other ongoing riliprubart development programs, including the Phase 3 VITALIZE study (NCT06290141), which is evaluating the therapy in CIDP patients receiving intravenous immunoglobulin (IVIg).
Scientific and Clinical Context
Riliprubart (SAR445088, BIVV020) is an investigational humanized IgG4 monoclonal antibody that selectively inhibits activated C1s, a protein within the classical complement pathway of the innate immune system. By blocking C1s activity, the therapy is intended to suppress complement-mediated inflammation that contributes to nerve demyelination and axonal injury in CIDP.
CIDP is a rare autoimmune neurological disorder characterized by progressive weakness, impaired sensation, and functional disability. The disease occurs when the immune system attacks the myelin sheath surrounding peripheral nerves, disrupting nerve signal transmission. Although several treatment options are available, significant unmet need remains. Approximately 30% of patients do not respond to standard therapies, while many responders continue to experience persistent symptoms and require long-term treatment.
Trial and Development Details
MOBILIZE was a Phase 3 study evaluating riliprubart in patients with CIDP refractory to standard-of-care treatment. While Sanofi did not disclose detailed efficacy findings from the interim analysis, the independent monitoring committee determined that continuing the study was unlikely to generate sufficient evidence of clinical benefit.
Investigators identified no new safety concerns associated with riliprubart during the review. Sanofi plans to work closely with study investigators and clinical sites to ensure an orderly wind-down of the trial and appropriate transition of care for enrolled participants.
Executive Perspective
The company expressed gratitude to patients, caregivers, and investigators who participated in the study. Sanofi also emphasized its commitment to conducting a comprehensive analysis of the accumulated data, which may help advance scientific understanding of CIDP and inform future research efforts in complement-mediated neurological diseases.
Path Forward
Sanofi will evaluate the impact of the MOBILIZE outcome on the broader riliprubart development program, including the ongoing VITALIZE Phase 3 trial. Further analyses may clarify whether specific patient populations could still benefit from complement pathway inhibition in CIDP.
The company stated that terminating the study will not result in significant financial costs and does not alter its 2026 financial guidance. Riliprubart remains an investigational therapy and has not been approved by any regulatory authority.
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About the Writer
Shaik Yasmeen (LinkedIn) is a Pharm.D graduate with interests in clinical pharmacy, pharmacovigilance, and medical writing. She has gained experience through hospital clinical postings, patient case reviews, case presentations, and literature evaluation. Passionate about evidence-based healthcare, she is committed to creating accurate and engaging medical content while continuously expanding her professional knowledge.