FDA Grants Breakthrough Therapy Designation to Sanofi and Sobi’s Experimental Treatment for Hemophilia A

The U.S. Food and Drug Administration granted Breakthrough Therapy designation to efanesoctocog alfa for the treatment of people with hemophilia A, a rare and life-threatening bleeding disorder.

Photo: John Reed, global head of research and development at Sanofi

The FDA granted the company’s the designation based on data from the pivotal XTEND-1 phase 3 study. Sanofi and Sobi are collaborating on the development and commercialization of efanesoctocog alfa.

“The Breakthrough Therapy designation highlights efanesoctocog alfa’s potential to transform treatment for people with hemophilia A by providing higher protection for longer duration,” said John Reed, global head of research and development at Sanofi. “This potential new class of factor VIII therapy represents how we are boldly advancing science to address unmet needs for the hemophilia community.”

Hemophilia A occurs in about one in 5,000 male births annually, and more rarely in females. It is a lifelong condition in which the ability of a person’s blood to clot is impaired due to a coagulation factor deficiency. People with hemophilia can experience bleeding episodes that can cause pain, irreversible joint damage, and life-threatening hemorrhages. Unmet medical needs remain for people with hemophilia to strengthen protection, reduce treatment burden, and improve quality of life.

Efanesoctocog alfa is a novel and experimental recombinant factor VIII therapy that is designed to extend protection from bleeds with once-weekly prophylactic dosing for people with hemophilia A. It builds on the innovative Fc fusion technology by adding a region of von Willebrand factor and XTEN polypeptides to extend its time in circulation. It is the first investigational factor VIII therapy that has been shown to break through the von Willebrand factor ceiling, which imposes a half-life limitation on current factor VIII therapies. Efanesoctocog alfa is currently under clinical investigation and its safety and efficacy have not been evaluated by any regulatory authority.

Topline results from the pivotal XTEND-1 Phase 3 study demonstrate efanesoctocog alfa met the primary endpoint, showing a clinically meaningful prevention of bleeds in people with severe hemophilia A over a 52-week period. Importantly, the key secondary endpoint was also met, demonstrating that efanesoctocog alfa was superior to prior prophylactic factor VIII replacement therapy in preventing bleeding events based on an 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.

Data from the XTEND-1 Phase 3 study are expected to be shared at an upcoming medical meeting, and those data will serve as the basis for submission to FDA mid-year 2022. The FDA granted efanesoctocog alfa Orphan Drug designation in August 2017 and Fast Track designation in February 2021. The European Commission also granted efanesoctocog alfa Orphan Drug designation in June 2019. Regulatory submission in the EU will follow availability of data from the ongoing XTEND-Kids pediatric study, expected in 2023.

Breakthrough Therapy designation is designed to expedite the development and review of drugs in the United States that target serious or life-threatening conditions. Drugs qualifying for this designation must show preliminary clinical evidence that the drug may demonstrate a substantial improvement on clinically significant endpoints over available therapies.

Sobi and Sanofi collaborate on the development and commercialization of efanesoctocog alfa, an investigational factor VIII therapy with the potential to provide high sustained factor activity levels with once-weekly dosing for people with hemophilia A. Sobi has final development and commercialization rights in the Sobi territory (Europe, North Africa, Russia and most Middle Eastern markets). Sanofi has final development and commercialization rights in North America and all other regions in the world excluding the Sobi territory.

Author: Rare Daily Staff