RARE Daily

FDA Grants Priority Review to Efanesoctocog Alfa for People with Hemophilia A

August 30, 2022

The U.S. Food and Drug Administration has accepted for priority review the Biologics License Application for efanesoctocog alfa for the treatment of hemophilia A, a rare and life-threatening bleeding disorder.

Photo: Dietmar Berger, global head of Development and chief medical officer at Sanofi

The target action date for the FDA decision is February 28, 2023. Sanofi and Sobi are collaborating on the development and commercialization of efanesoctocog alfa.

“Factor therapy remains a cornerstone of hemophilia treatment, but innovation has been needed in this area to address challenges related to bleed protection and cumbersome treatment regimens, said Steve Pipe, professor and director Pediatric Hemophilia and Coagulation Disorders Program, University of Michigan. “If approved, efanesoctocog alfa can deliver close to normal factor activity levels for the majority of the week, potentially offering a new tier of protection. Such therapeutic benefits would represent important advances in unmet medical needs for people with hemophilia A and may transform the prophylactic treatment landscape.”

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. Efanesoctocog alfa is currently under clinical investigation and its safety and efficacy have not been evaluated by any regulatory authority.

The application is supported by data from the pivotal XTEND-1 phase 3 study, an open-label, non-randomized interventional study assessing the safety, efficacy, and pharmacokinetics of once-weekly efanesoctocog alfa in people 12 years of age or older with severe hemophilia A who were previously treated with factor VIII replacement therapy.

The primary efficacy endpoint was the annualized bleeding rate (ABR) in Arm A, and the key secondary endpoint was an intra-patient comparison of ABR during the efanesoctocog alfa weekly prophylaxis treatment period versus the prior factor VIII prophylaxis ABR for participants in Arm A who had participated in a previous observational study.

The data demonstrated a clinically meaningful prevention of bleeds and superiority to prior factor prophylaxis 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 percent of participants overall) were headache, arthralgia, fall, and back pain.

“The results from the pivotal XTEND-1 Phase 3 study demonstrate efanesoctocog alfa’s ability to reduce annualized bleeding rates, which supports its potential as a therapy with best-in-disease efficacy,” said Dietmar Berger, global head of Development and chief medical officer at Sanofi.

The FDA grants priority review to therapies that have the potential to provide significant improvements in the treatment, diagnosis, or prevention of serious conditions. Efanesoctocog alfa received Breakthrough Therapy designation from the FDA in May 2022, the first factor VIII therapy to receive this recognition. The FDA also granted efanesoctocog alfa Orphan Drug designation in August 2017 and Fast Track designation in February 2021.

Regulatory submission in the EU will follow availability of data from the ongoing XTEND-Kids pediatric study, with both events expected in 2023. The European Commission granted efanesoctocog alfa Orphan Drug designation in June 2019.

Sobi has final development and commercialization rights in the Europe, North Africa, Russia, and most Middle Eastern markets, and Sanofi has final development and commercialization rights in North America and the rest of the world.

Author: Rare Daily Staff

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