RARE Daily

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

June 2, 2022

The U.S. Food and Drug Administration granted Breakthrough Therapy designation to Sanofi and Swedish Orphan Biovitrum’s efanesoctocog alfa for the treatment of people with the rare bleeding disorder hemophilia A.

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

Hemophilia 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. Hemophilia A occurs in about one in 5,000 male births annually, and more rarely in females. People with hemophilia can experience bleeding episodes that can cause pain, irreversible joint damage, and life-threatening hemorrhages.

Efanesoctocog alfa is a novel and investigational 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.

Breakthrough Therapy designation is designed to expedite the development and review of drugs in the US 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.

The designation was based on data from the pivotal XTEND-1 phase 3 study. Topline results from the pivotal XTEND-1 phase 3 study demonstrated that 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 per cent of participants overall) were headache, arthralgia, fall, and back pain.

“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.”

Author: Rare Daily Staff

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