FDA Approves First-in-Class Factor VIII Therapy for Hemophilia A

The FDA has approved Altuviiio [antihemophilic factor (recombinant), Fc-VWF-XTEN fusion protein-ehtl; Sanofi], a von Willebrand Factor (VWF) independent recombinant factor VIII therapy for the treatment of hemophilia A.

The first-in-class, high-sustained factor VIII replacement therapy, previously called efanesoctocog alfa, is indicated for routine prophylaxis and on-demand treatment to control bleeding episodes and for perioperative management in adults and children with hemophilia A.

"[The] approval of Altuviiio allows patients and physicians to reimagine living with hemophilia,” said Paul Hudson, CEO, Sanofi, in a press release. “The high sustained factor activity levels that can be achieved with Altuviiio have the potential to change the hemophilia landscape. For the first time, with a once-weekly dose, powerful bleed protection is a reality for patients.”

Altuviiio is the first and only therapy for hemophilia A that provides normal to near-normal factor activity levels—over 40%—for most of the week with once-weekly dosing, according to Sanofi. The efficacy of the treatment was demonstrated by results from the XTEND-1 phase 3 study, which were presented at the 30th International Society of Thrombosis and Haemostasis Congress.

The findings showed a clinically meaningful prevention of bleeds and superiority to prior factor prophylaxis based on an intra-patient comparison. Altuviiio was generally well-tolerated and inhibitor development factor VIII was not detected. The most common treatment-emergent adverse events were arthralgia, back pain, falls, and headaches.

The trial’s primary efficacy endpoint was the annualized bleeding rate (ABR) in arm A. The key secondary endpoint was an intra-patient comparison of ABR during the Altuviiio weekly prophylaxis treatment period compared with the prior factor VIII prophylaxis ABR for individuals in arm A. Those individuals participated in a previous observational study, Study 242HA201/OBS16221.

The interventional, non-randomized, and open-label study assessed the efficacy, safety, and pharmacokinetics of Altuviiio at a once-a-week dosage in individuals aged 12 years and older with severe hemophilia A who were previously treated with factor VIII replacement therapy.

Investigators separated individuals into 2 parallel treatment arms: the prophylaxis arm A, in which patients who had received prior factor VIII prophylaxis were treated with Altuviiio prophylaxis once a week intravenously for 52 weeks, and the on-demand arm B, in which patients who had received prior on-demand factor VIII therapy began 26 weeks of on-demand Altuviiio, switching to once-weekly prophylaxis for an additional 26 weeks.

Data from XTEND-1 showed once-weekly Altuviiio prophylaxis met the primary endpoint by conferring significant bleed protection for patients with severe hemophilia A with a mean ABR of 0.70 (95% CI: 0.5-1.0) and a median ABR of 0.0 (Q1, Q3: 0.0, 1.0). The drug also met the key secondary endpoint with a significant ABR decrease of 77% compared with prior factor prophylaxis based on an intra-patient comparison (95% CI:58%-87%).

Altuviiio also provided prevention of joint bleeds, with a median annualized joint bleeding rate of 0 (Q1, Q3: 0.0, 1.0) and 100% resolution of target joints. Further, the treatment provided mean factor VIII activity greater than 40% for most of the week and greater than 10% at day 7, both of which were associated with a low bleed risk.

Data from XTEND-Kids found that patients younger than 12 years of age administered once-weekly Altuviiio for 26 weeks (n=23) had a mean ABR of 0.5 (95% CI: 0.2-1.3) and a median ABR of 0 (Q1, Q3: 0.0, 1.3).

Altuviiio previously received breakthrough therapy designation from the FDA in May 2022 and was the first factor VIII therapy to receive this designation. Additionally, the FDA granted it orphan drug designation in August 2017 and fast-track designation in February 2021.

“This approval marks an important clinical advancement for the hemophilia community because we have an option that can achieve higher levels of factor activity with a single simplified weekly dose. By maintaining high levels of factor activity throughout the week, patients can be confident in the bleed protection Altuviiio offers,” said Lynn Malec, MD, medical director of Comprehensive Center for Bleeding Disorders and associate investigator at The Versiti Blood Research Institute, and associate professor of Medicine and Pediatrics at The Medical College of Wisconsin.

Reference

FDA approves once-weekly ALTUVIIIO™, a new class of factor VIII therapy for hemophilia A that offers significant bleed protection. Sanofi. News release. https://www.news.sanofi.us/2023-02-23-FDA-approves-once-weekly-ALTUVIIIO-TM-,-a-new-class-of-factor-VIII-therapy-for-hemophilia-A-that-offers-significant-bleed-protection. February 23, 2023.