FDA Prioritizes Review of Emicizumab for Hemophilia A Without Factor VIII Inhibitors

The biologic was previously approved for patients with hemophilia A with factor VIII inhibitors, but additional results indicated efficacy for patient without factor VIII inhibitors as well.

The US Food and Drug Administration (FDA) has accepted a supplemental Biologics License Application (sBLA) and granted Priority Review to emicizumab-kxwh (Hemlibra, Genentech) for adults and children with hemophilia A without factor VIII inhibitors.

Emicizumab-kxwh is an antibody that, in place of missing factor VIII, joins factor IXa and factor X, activating the natural coagulation process in people with hemophilia A who lack factor VIII.

“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,” said Sandra Horning, MD, chief medical officer and Head of Global Product Development.

The sBLA is supported by data from Genentech’s HAVEN 3 study of adults and adolescents aged 12 years and older with hemophilia A without factor VIII inhibitors. The open-label phase 3 study included 152 patients who were previously treated with factor VIII therapy either on-demand or for prophylaxis.

The study found that patients treated with emicizumab-kxwh prophylaxis every week or every other week experienced a 96% (p<0.0001) and 97% (p<0.0001) reduction in treated bleeds, respectively, compared to patients who were not treated with prophylaxis.

Additionally, 55.6% (95% CI: 38.1, 72.1) of patients treated with emicizumab-kxwh every week and 60% (95% CI: 42.1, 76.1) of those treated with emicizumab-kxwh every 2 weeks experienced no treated bleeds, compared to 0% (95% CI: 0.0; 18.5) of patients not given prophylaxis.

HAVEN 3 reported no serious adverse events related to emicizumab-kxwh. The most common adverse events occurring in at least 5% of the patients were injection site reactions, joint pain (arthralgia), common cold symptoms (nasopharyngitis), 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,” said Horning. “We look forward to working with the FDA to hopefully bring Hemlibra to all people with hemophilia A as quickly as possible.”

Earlier this year, emicizumab-kxwh was granted Breakthrough Therapy status by the FDA for patients with hemophilia A without factor VIII inhibitors. The treatment was previously approved by the FDA for hemophilia A patients with factor VIII inhibitors based on results from the HAVEN 1 and HAVEN 2 studies.

Given the Priority Review, the company expects a decision from the FDA regarding this sBLA by October 4, 2018.