Efanesoctocog alfa meets endpoints in pivotal study in hemophilia A

French pharma major Sanofi (Euronext: SAN) and Swedish Orphan Biovitrum (STO: SOBI) have announced positive top-line results from the pivotal XTEND-1 Phase III study evaluating the safety, efficacy and pharmacokinetics of efanesoctocog alfa (BIVV001) in previously treated patients ≥12 years of age with severe hemophilia A.

The study met the primary endpoint, showing a clinically meaningful prevention of bleeds in people with severe hemophilia A receiving weekly prophylaxis with efanesoctocog alfa over a period of 52 weeks. The median annualized bleeding rate (ABR) was 0 with a mean ABR of 0.71. The key secondary endpoint was also met, demonstrating once-weekly efanesoctocog alfa was superior to prior prophylactic factor VIII replacement therapy, showing a statistically-significant reduction in ABR based on intra-patient comparison. Efanesoctocog alfa was well-tolerated, and inhibitor development to factor VIII was not detected. The most common treatment-emergent adverse events (>5% of participants overall) were headache, arthralgia, fall, and back pain.

Sanofi gained rights to efanesoctocog alfa through its $11.6 billion acquisition of Bioverativ in 2018.