FDA Approves Hemlibra to Treat for Hemophilia A Patients with Factor VIII Inhibitors

The U.S. Food and Drug Administration (FDA) has approved Hemlibra (emicizumab-kxwh) for routine prophylaxis to prevent or lessen bleeding episodes in children and adults with hemophilia A with factor VIII inhibitors, Genentech announced.

Hemlibra is first newly approved treatment for this patient group in almost 20 years, the company said.

The approval comes on the heels of positive results from two of the largest clinical studies in patients with hemophilia A with inhibitors, HAVEN 1 (NCT02622321) and HAVEN 2 (NCT02795767). Results indicated that Hemlibra significantly reduced bleeds in both adult and pediatric patients with hemophilia A.

Almost 1 in 3 hemophilia A patients that are treated with factor VIII replacement therapy tend to develop inhibitors against factor VIII, which can lead to higher risk for bleeds and long-term joint damage.

Hemlibra bypasses that problem as it is a bispecific factor IXa- and factor X-directed antibody. This means its use can bring together the two proteins, which will activate the natural clotting cascade. Hemlibra also requires only once a week use as an injection under the skin.

“People with hemophilia A who develop inhibitors face significant challenges preventing bleeds and typically require infusions of medicine multiple times a week, which can be especially difficult for young children and their families,” Dr. Guy Young, professor of pediatrics at University of Southern California Keck School of Medicine, said in a press release. “This new medicine has been shown to reduce the frequency of bleeds compared to the currently available medicines and only needs to be injected once a week. This could make a meaningful difference for these children.”

The Phase 3 HAVEN 1 study, conducted in patients 12 years of age or older with hemophilia A with inhibitors, showed that treatment led to an 87% reduction in bleeds compared to patients not did not receive prophylaxis. An analysis of data collected prior to the study’s start on patients using a different bypassing agent (BPA) as prophylaxis treatment also showed that Hemlibra  prophylaxis  led to a 79% significant reduction in bleeds.

In the HAVEN 2 study, in patients younger than 12 years with hemophilia A with inhibitors, showed that 87% of patients given Hemlibra had no bleeds. Likewise, the analysis of pre-study BPA use in young children found a 99% reduction in bleeds while on Hemlibra.

“We believe HEMLIBRA will improve protection against bleeds and reduce the treatment administration burden for people with hemophilia A with inhibitors, and we are committed to helping them access this medicine,” said Sandra Horning,  chief medical officer and head of Global Product Development at Genentech.

Hemlibra is expected to be available to U.S. patients soon, the company said in its release.

Common side effects of treatment were injection site reactions, headache, and joint pain (arthralgia).

In Europe, data from HAVEN 1 and HAVEN 2 trials are under review for approval.

Two additional Phase 3 studies are evaluating the treatment’s efficacy and safety at other doses and schedules. HAVEN 3 (NCT02847637) is being conducted in patients 12 years and older with severe hemophilia A without inhibitors to factor VIII with doses given once a week (1.5 mg/kg) or once every two weeks (3 mg/kg). HAVEN 4 (NCT03020160) is being conducted in patients 12 years of age or older, with or without inhibitors, with 6 mg/kg doses given every four weeks after an initial one-month “loading” period.