The Food and Drug Administration has approved emicizumab-kxwh (Hemlibra) for the prevention or reduction of bleeding episodes for adult and pediatric patients with hemophilia A with Factor VIII inhibitors.
The approval, announced on Nov. 16, is significant since Factor VIII inhibitors can make available treatments less effective. Emicizumab-kxwh bridges other Factors (proteins) in the blood to restore clotting function and is injected subcutaneously as a weekly prophylactic treatment.
The drug received the FDA’s Priority Review, Breakthrough Therapy, and Orphan Drug designations.
It was shown to be safe and effective in two clinical trials, one of boys and men aged 12 years and older and the other of boys younger than 12 years. In the first trial, patients taking emicizumab-kxwh had an 87% reduction in the rate of treated bleeding episodes per year, compared with patients not receiving prophylactic treatment (2.9 vs. 23.3; P less than .0001).
In the second trial, 87% of the children receiving emicizumab-kxwh did not experience a bleeding episode that required treatment.
The most common adverse events were injection site reactions, headache, and arthralgia. The drug labeling includes a boxed warning about the possibility of thrombotic microangiopathy and thromboembolism in patients given an activated prothrombin complex concentrate rescue treatment for 24 hours or more while taking emicizumab-kxwh.