The FDA approved efanesoctocog alfa, a once-weekly treatment for children and adults with hemophilia A.

The approval applies to use of the factor VIII replacement therapy as routine prophylaxis to reduce the frequency of bleeding episodes, on-demand treatment for control of bleeds, and for perioperative management of bleeding. Efanesoctocog alfa (Altuviiio; Bioverativ Therapeutics, Sanofi) is not indicated for treatment of von Willebrand disease.

“This is both a treatment and a prophylaxis, whereas other novel therapies are only prevention drugs,” Margaret V. Ragni, MD, MPH, professor of medicine and clinical translational science at University of Pittsburgh School of Medicine, medical director at Hemophilia Center of Western Pennsylvania and expert with ASH, told Healio. “By all measures that we use, this treatment is safe, it is very effective and it is less burdensome.”

Efanesoctocog alfa, a novel fusion protein, is designed to be given as once-weekly recombinant factor VIII replacement therapy to prevent bleeding. The FDA previously granted the treatment priority review, in addition to breakthrough therapy designation for the treatment of hemophilia A.

Margaret V. Ragni

The FDA based approval on results of the phase 3 XTEND-1 trial, in which efanesoctocog alfa met the primary endpoint by providing significant bleed protection with a mean annualized bleeding rate of 0.7 (95% CI, 0.5-1) and median annualized bleeding rate of 0 (Q1, Q3: 0, 1). The treatment also conferred a significant 77% (95% CI, 58-87) reduction in intrapatient annualized bleed rate compared with factor VIII prophylaxis therapy.

The impact efanesoctocog alfa will have on clinical care is unclear at this point because it works differently than emicizumab-kxwh (Hemlibra, Genentech), another factor VIII replacement therapy, according to Ragni. It’s too early to tell if a drug that is both preventive and a treatment produces a “medically less impressive outcome,” Ragni said.

Nevertheless, if efanesoctocog alfa continues to provide significant bleed protection, “this can be a game-changer in the sense that it’s a single go-to drug,” she added.

Studies leading to its approval showed no significant treatment-related safety issues, Ragni said.

“It caused minor side effects that we have come to expect from drugs of this nature — mostly headaches,” added Ragni, who was not involved in the studies that led to the drug’s approval.