Sanofi, scarred by Roche scrap, hits goal in once-weekly hemophilia A trial and plots race to regulators

Sanofi is fighting back against Roche in the hemophilia A market. Having seen Hemlibra eat into sales of its long-acting factor VIII (FVIII) therapy, Sanofi has now posted positive phase 3 data on its once-weekly successor, positioning the French pharma and partner Sobi to start filing for approvals.

Efanesoctocog alfa, also known as BIVV001, is designed to address the limitations of current hemophilia treatments. Existing FVIII treatments require patients to undergo multiple intravenous infusions a week. Those infusions provide high protection, enabling patients to be more active, but still leave them at risk when FVIII levels are at their trough level or if they miss an infusion. In contrast, Roche’s Hemlibra is given less frequently, but many patients still suffer acute bleeds that require additional factor therapy.

Sanofi previously released data suggesting work to extend the half-life of efanesoctocog alfa, notably by decoupling the FVIII replacement from endogenous von Willebrand factor, had paid off, encouraging it to advance into phase 3. Now, Sanofi has data from the phase 3 clinical trial.

The clinical trial enrolled 159 people with severe hemophilia A aged 12 years and up. Participants, who had previously had FVIII replacement therapy, either took a weekly prophylactic dose of efanesoctocog alfa for 52 weeks, or received doses as needed for 26 weeks followed by weekly prophylaxis for another 26 weeks. The primary endpoint covered annualized bleed rate (ABR) in the 52-week prophylaxis arm.

Median ABR was 0 and mean ABR was 0.71, leading Sanofi’s chief medical officer Dietmar Berger, M.D., Ph.D., to hail the “very low annualized bleeding rate” in the top-line data as evidence of “efanesoctocog alfa’s potential to transform hemophilia A therapy.”

The study also met a key secondary endpoint. The endpoint compared the ABR of people in the 52-week prophylaxis arm to their own historical ABR from an earlier observational study in which they received prophylactic FVIII replacement therapy. Sanofi saw a statistically significant reduction in ABR, suggesting efanesoctocog alfa may be more effective and more convenient than existing treatment options.

Sanofi is now preparing to find out whether it can translate the data into regulatory and commercial successes. Submissions will start this year and continue into 2023, when a filing in the EU is planned for after the release of data from a pediatric study. Sanofi, which acquired efanesoctocog alfa in its buyout of Bioverativ, will share commercialization with Sobi, which has rights in Europe, North Africa, Russia and most Middle Eastern markets.