The US Food and Drug Administration (FDA) has approved AFSTYLA®, a long-lasting recombinant factor VIII (rFVIII), “single-chain” therapy manufactured by CSL Behring. AFSTYLA® is indicated in adults and children with hemophilia A for routine prophylaxis to reduce the frequency of bleeding episodes, on-demand treatment for control of bleeding episodes and the perioperative management of bleeding. Because AFSTYLA® was developed as one molecular bond (also known as a covalent bond), its singular structure enhances rFVIII stability and helps the therapy remain active longer.

AFSTYLA®’s approval was based on results from a clinical development program called AFFINITY. The program was designed to evaluate the safety and efficacy of AFSTYLA® in children, adolescents and adults with hemophilia A. Results showed a median annualized spontaneous bleeding rate (AsBR) of 0 in adults, adolescents and children undergoing prophylaxis. The overall median annualized bleeding rate (ABR) was 1.14 in adult and adolescent patients, and 3.69 in children less than 12 years old using AFSTYLA®  prophylactically.

A total of 1,195 bleeds were treated during the study, including 848 in adults and adolescents, and 347 in children. Of those, 94% of bleeds in adult and adolescent patients, and 96% of bleeding events in pediatric patients were effectively controlled with no more than two weekly infusions of AFSTYLA®. Further, 81% of bleeds in adult and adolescent patients, and 86% of bleeding events in pediatric patients were effectively controlled by only one infusion per week.

During the study, 13 adult and adolescent patients underwent surgical procedures (16 total surgeries). In these surgical settings AFSTYLA®’s hemostatic efficacy, which refers to a therapies’ effectiveness in stopping bleeds, was rated as “excellent” 15 times and “good” once. The most common adverse reactions reported in clinical trials were dizziness and hypersensitivity. In addition, no inhibitors were observed.

“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  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 company expects AFSTYLA® to become available this summer.

Source: CSL Behring news release dated May 26, 2016