FDA grants priority review to Hemlibra for hemophilia A without factor VIII inhibitors

The FDA granted priority review to emicizumab-kxwh for treatment of adults and children with hemophilia A without factor VIII inhibitors, according to the agent’s manufacturer.

Emicizumab-kxwh (Hemlibra, Genentech) already is approved for routine prophylaxis to prevent or reduce frequency of bleeding episodes among adult and children with hemophilia A with factor VIII inhibitors.

The priority review designation for the new indication is based on results of the HAVEN 3 study.

The multicenter, open-label, randomized phase 3 study included 152 patients aged 12 years or older with hemophilia A without factor VIII inhibitors. Patients underwent prior treatment with factor VIII therapy, either on demand or for prophylaxis.

Patients who previously received on-demand factor VIII treatment were randomly assigned 2:2:1 to subcutaneous emicizumab-kxwh prophylaxis at 3 mg/kg per week for 4 weeks, followed by 1.5 mg/kg per week until study conclusion; subcutaneous prophylaxis at 3 mg/kg per week for 4 weeks, followed by 3 mg/kg every 2 weeks for at least 24 weeks; or no prophylaxis.

Patients who received emicizumab-kxwh prophylaxis every week achieved a 96% reduction in treated bleeds compared with those who received no prophylaxis (P < .0001). Patients who received prophylaxis every 2 weeks achieved a 97% reduction in treated bleeds (P < .0001).

In addition, 55.6% of those who received weekly prophylaxis and 60% of those who received prophylaxis every 2 weeks experienced no treated bleeds, compared with no patients in the group that did not receive prophylaxis.

A separate study arm included patients who previously received factor VIII prophylaxis in a noninterventional study. These patients received subcutaneous emicizumab-kxwh prophylaxis 3 mg/kg every week for 4 weeks, followed by 1.5 mg/kg every week until study conclusion.

For these patients, emicizumab-kxwh led to a 68% reduction in treated bleeds (P < .0001), making it the first agent to demonstrate superior efficacy to previous treatment with standard factor VIII prophylaxis.

Researchers observed no unexpected or serious treatment-related adverse events in HAVEN 3. The most common adverse events included injection site reactions, joint pain, common cold symptoms, headache, upper respiratory tract infection and influenza.

“People with hemophilia A can face significant challenges in managing their condition and may need to adapt their daily lives to avoid bleeds and accommodate treatment,” Sandra Horning, MD, chief medical officer and head of global product development at Genentech, said in a company-issued press release. “We believe the FDA’s decision to grant priority review to Hemlibra underscores its potential to improve the standard of care for people without factor VIII inhibitors and to help reduce treatment burden by offering more flexible subcutaneous dosing options. We look forward to working with the FDA to hopefully bring Hemlibra to all people with hemophilia A as quickly as possible.”

The FDA is expected to make a decision on approval by Oct. 4.