CSL Behring, a global biotherapeutics leader, announced that the US Food and Drug Administration (FDA) has approved Afstyla [Antihemophilic Factor (Recombinant), Single Chain], its novel long-lasting recombinant factor VIII single-chain therapy for adults and children with haemophilia A.

Afstyla is the first and only single-chain product for haemophilia A that is specifically designed for long-lasting protection from bleeds with two to three times weekly dosing. In clinical trials, patients undergoing prophylaxis with Afstyla experienced a median annualized spontaneous bleeding rate (AsBR) of 0.00. Once activated, Afstyla is identical to natural factor VIII. Clinical trials of Afstyla demonstrated a strong safety profile with no inhibitors observed.

Afstyla is indicated in adults and children with haemophilia A for routine prophylaxis to reduce the frequency of bleeding episodes; on-demand treatment and control of bleeding episodes; and the perioperative management of bleeding. Afstyla is expected to be available early this summer.

“FDA’s approval of the first recombinant single-chain therapy that offers long-lasting hemostatic efficacy provides an important new treatment option for patients and healthcare providers as it has been specifically designed for increased molecular stability and duration of action,” said Dr. Lisa Boggio, Assistant Professor of Internal Medicine, Hematology and Oncology, Clinical Director of the Rush Hemophilia and Thrombophilia Center, and AFFINITY clinical development program study investigator. “Afstyla offers patients an opportunity for excellent efficacy with a strong safety profile and twice-weekly dosing -- potentially helping patients to fit treatment into their active lives.”

The approval of Afstyla is based on results from the AFFINITY clinical development program. AFFINITY includes two pivotal and one extension open-label multi-center studies evaluating the safety and efficacy of Afstyla in children, adolescents and adults with haemophilia A.

"For 100 years, CSL has focused on researching and developing innovative therapies that meet the treatment challenges patients face,” said Dr. Andrew Cuthbertson, chief scientific officer and director of R&D, CSL Limited. "The approval of Afstyla, an innovative and effective haemophilia A therapy, further demonstrates CSL’s dedication to developing and delivering novel therapies that have the potential to improve patients’ lives. We are very excited to add this treatment to our industry-leading portfolio of coagulation therapies and look forward to the positive impact Afstyla can have on patients with haemophilia A.”

Primarily affecting males, hemophilia A is a congenital bleeding disorder characterized by deficient or defective factor VIII. People with haemophilia A may experience prolonged or spontaneous bleeding, especially into the muscles, joints or internal organs. According to the United States Centers for Disease Control and Prevention (CDC), the condition affects approximately 1 in 6,000 male births.

The data from the AFFINITY clinical development program showed a median annualized spontaneous bleeding rate (AsBR) of 0.00 in both the adult and adolescent study as well as the pediatric study. The median annualized bleeding rate (ABR) was 1.14 in adult and adolescent patients and 3.69 in children less than 12 years of age using Afstyla prophylactically. Of 1,195 bleeds treated in the pivotal study (848 in adults and adolescents; 347 in children), 94 percent of bleeds in adult and adolescent patients and 96 percent of bleeding events in pediatric patients were effectively controlled with no more than two infusions of Afstyla weekly; 81 percent of bleeds in adult and adolescent patients and 86 percent of bleeding events in pediatric patients were effectively controlled by only one infusion. The majority of bleeding events treated with Afstyla (94 percent in adults and adolescents; 96 percent in children) were rated as excellent or good. Of the 13 adult or adolescent patients in the study who underwent surgical procedures (16 total surgeries), hemostatic efficacy of Afstyla was rated as excellent (15 times) or good (once). The most common adverse reactions reported in clinical trials were dizziness and hypersensitivity.

Afstyla (also known as rVIII-Single Chain) for haemophilia A is CSL Behring’s recombinant single-chain factor VIII specifically designed for greater molecular stability and longer duration of action. Afstyla uses a covalent bond that forms one structural entity, a single polypeptide-chain, to improve the stability of factor VIII and provide longer-lasting factor VIII activity. Regulatory agencies in Europe, Switzerland and Australia are currently reviewing CSL Behring’s license applications for Afstyla.