Sanofi stopped its Phase 3 MOBILIZE study of riliprubart in chronic inflammatory demyelinating polyneuropathy (CIDP) after an independent monitoring board determined the trial was unlikely to achieve sufficient efficacy. The decision came during an interim analysis, with Sanofi reporting no safety concerns but concluding the efficacy signal did not support continuation. The setback affects a complement-inhibitor approach targeting the classical complement pathway, and it lands as investors weigh how competitive the CIDP landscape will be for next-generation agents. Sanofi said it is now evaluating the future of the riliprubart program, including whether to continue another Phase 3 study, VITALIZE. The news also highlighted potential read-through risk for competitors testing related mechanisms in CIDP with different trial designs. Investors appeared to react more sharply to the smaller rival Dianthus in the immediate aftermath. As Sanofi tries to stabilize its pipeline trajectory under a leadership reset, the stop-for-futility outcome adds to the urgency of delivering clearer late-stage efficacy differentiation across its immunology and neurology franchises.