SOBI’s and Sanofi’s Haemophilia A Drug Met the Primary and Key Secondary Endpoints

Swedish Orphan Biovitrum (SOBI) and Sanofi have announced positive top-line results from the pivotal XTEND-1 phase 3 study evaluating the safety, efficacy and pharmacokinetics of efanesoctocog alfa (BIVV001) in previously treated patients ≥12 years of age with severe haemophilia A.

The companies said that the study met the primary endpoint, showing a clinically meaningful prevention of bleeds in people with severe haemophilia A receiving weekly prophylaxis with efanesoctocog alfa over a period of 52 weeks. The median annualised 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 per cent of participants overall) were headache, arthralgia, fall, and back pain.

“We believe once weekly efanesoctocog alfa has the potential to represent a new class of factor VIII therapy designed to provide high sustained factor VIII activity levels near normal for the majority of the week,” said Anders Ullman, MD, PhD, Head of Research & Development and Chief Medical Officer at Sobi. “We look forward to sharing these phase 3 results, including data on physical health, pain and joint health at future medical meetings.”

Haemophilia A is a rare, genetic disorder in which the ability of a person’s blood to clot is impaired due to a lack of factor VIII. Haemophilia A occurs in about one in 5,000 male births annually, and more rarely in females. People with haemophilia can experience bleeding episodes that can cause pain, irreversible joint damage and life-threatening haemorrhages.

“While advances have been made in the treatment of haemophilia, unmet medical needs still exist. These positive top-line data, showing a very low annualised bleeding rate, enhance efanesoctocog alfa’s potential to transform haemophilia A therapy. We believe efanesoctocog alfa provides higher protection for longer duration with reduced treatment burden of once-weekly dosing, and we look forward to working with regulators to bring this therapy to patients as soon as possible,” said Dietmar Berger, MD, PhD, Global Head of Development at Sanofi.

The companies noted that the data will be the basis for submission to regulatory authorities around the globe beginning this year. Submission in the EU will follow availability of data from the ongoing XTEND-Kids paediatric study, expected in 2023. Efanesoctocog alfa was granted Orphan Drug Designation by the US Food and Drug Administration (FDA) in August 2017 and the European Commission in June 2019. The US FDA granted Fast Track Designation in February 2021. Efanesoctocog alfa is currently under clinical investigation and its safety and efficacy have not been evaluated by any regulatory authority.