FDA Approves Prophylactic Hemophilia Drug to Prevent Bleeding

The FDA granted approval to emicizumab-kxwh (Hemlibra) to prevent or lower the risk of bleeding in adults and children with hemophilia A who have developed antibodies for Factor VIII (FVIII) inhibitors, according to a press release.

Hemophilia A is a blood-clotting disorder that mainly affects men. Current estimates suggest that 1 in every 5000 men have hemophilia, 80% of whom have hemophilia A, according to the release.

Patients with hemophilia A are missing a gene that creates the clotting factor FVIII. As a result, patients can experience serious bleeding episodes, with some developing an immune response to FVIII, according to the release.

“Reducing the frequency or preventing bleeding episodes is an important part of disease management for patients with hemophilia. Today’s approval provides a new preventative treatment that has been shown to significantly reduce the number of bleeding episodes in patients with hemophilia A with Factor VIII inhibitors,” said Richard Pazdur, MD, acting director of the Office of Hematology and Oncology Products in the FDA Center for Drug Evaluation and Research and director of the FDA Oncology Center of Excellence. “In addition, patients treated with Hemlibra reported an improvement in their physical functioning.”

Emicizumab-kxwh bridges other clotting factors in the blood, which restores clotting ability. This prophylactic drug is administered as a weekly subcutaneous injection, according to the release.

“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,” said Guy Young, MD, director of Hemostasis and Thrombosis Program, Children’s Hospital Los Angeles, and professor of Pediatrics, University of Southern California Keck School of Medicine, Los Angeles, CA. “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 approval was based on positive safety and efficacy data from 2 clinical trials.

Included in the first trial were 109 males 12 years and older with hemophilia A with FVIII antibodies. Patients were randomized to receive emicizumab-kxwh or no prophylactic treatment.

The investigators found that patients treated with Emicizumab-kxwh experienced approximately 2.9 bleeding episodes that required treatment per year compared with 23.3 episodes per year for the other cohort, an 87% reduction, according to the release.

The trial also showed that emicizumab-kxwh improved hemophilia-related symptoms and physical function compared with patients who did not receive prophylactic treatment, the FDA reported.

Included in the second trial were 23 males 12 years and younger with hemophilia A with FVIII antibodies. During the trial, 87% of patients treated with emicizumab-kxwh did not experience a bleeding event.

The FDA advises that common side effects include injection site reactions, headache, and joint pain.

Emicizumab-kxwh comes with a boxed warning indicating that patients may be at risk of severe blood clots if they were administered activated prothrombin complex concentrate, a rescue therapy, to treat bleeds for 24 hours or more, according to the release.

Emicizumab-kxwh was previously granted priority review, breakthrough therapy, and orphan drug designations.

“Today’s approval of Hemlibra represents an important advancement for people with hemophilia A with inhibitors, who have struggled to manage their bleeding disorder and haven’t had a new medicine in nearly 20 years,” said Sandra Horning, MD, chief medical officer and head of Global Product Development, Genentech. “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.”