The drug, approved by the U.S. Food and Drug Administration (FDSA) in May, is the only single-chain product on the market specifically designed for reduction and control of bleeding episodes, routinely, during treatment or in perioperative management of bleeding, with two or three times weekly dosing.
Afstyla, also called rVIII-Single Chain, works by forming a single polypeptide-chain, through a covalent bond, that improves the stability of factor VIII and provides longer-lasting factor VIII activity. Defective or deficient factor VIII is the main characteristic of congenital bleeding disorder hemophilia A.
Approval was based on results from the Affinity clinical development program that included two pivotal and one extension clinical studies evaluating the safety and efficacy of the drug in children, adolescents and adults with hemophilia A. Patients undergoing prophylaxis with Afstyla experienced a median annualized spontaneous bleeding rate of 0.00. The median annualized bleeding rate was 1.14 for adult and adolescent patients and 3.69 for children less than 12 years old.
During the pivotal study, 1,195 bleeds (848 in adults and adolescents and 347 in children), were treated with Affinity. No more than two infusions of the drug effectively controlled 94% of the bleeds in adults and adolescents and 96% of bleeds in children. One infusion effectively controlled 81% of bleeds in adult and adolescent patients and 86% of bleeding events in pediatric patients.
The most common reactions reported were dizziness and hypersensitivity.
“We are proud to add AFSTYLA to our leading portfolio of bleeding disorder products and are particularly excited about the positive impact that treatment with AFSTYLA can have on the lives of patients with hemophilia A,” said Dr. Jerry Powell, medical director of CSL Behring’s North America Commercial Operations. “AFSTYLA is the second product from our innovative recombinant factor development program approved by the FDA in 2016. In March, IDELVION [Coagulation Factor IX (Recombinant), Albumin Fusion Protein], the first and only recombinant albumin fusion protein for hemophilia B, was approved by the FDA. Both AFSTYLA and IDELVION deliver on our promise to develop and provide innovative specialty biotherapies that help people with serious medical conditions live full lives.”
The drug is now under evaluation by regulatory agencies in Europe, Switzerland and Australia.