The Food and Drug Administration has approved emicizumab-kxwh (Hemlibra) for subcutaneous prophylactic treatment in hemophilia A without factor VIII inhibitors.
Genentech announced the new approval on Oct. 4 of this year. In 2017, the bispecific antibody, which targets both factors IXa and X, was approved for patients as young as newborns who had factor VIII inhibitors; the latest approval allows it to be used for patients without inhibitors as well.
The approval is based on a pair of trials. HAVEN 3 (NCT02847637) is a phase 3 trial in which investigators looked at emicizumab prophylaxis weekly or every other week, versus on-demand factor VIII treatment in patients without inhibitors. The study included 152 patients aged 12 years and older who were previously treated with factor VIII therapy.
Compared with patients not receiving prophylactic treatments, those receiving weekly doses had a 96% reduction in treated bleeds, and those receiving doses every other week saw a 97% reduction. Investigators also found that 55.6% of patients treated every week, 60% of those treated every other week, and 0% of those treated with no prophylaxis experienced zero bleeds; similarly, 91.7%, 94.3%, and 5.6% experienced three or fewer bleeds.
The single-arm HAVEN 4 (NCT03020160) trial evaluated dosing patients every 4 weeks among 48 patients aged 12 years and older, with or without inhibitors, and results showed that even that dosing regimen could lead to a clinically meaningful control of bleeds: 56.1% had no bleeds, and 90.2% had three or fewer bleeds.
The most common adverse reactions were joint pain, headache, and injection-site reaction. When emicizumab-kxwh is used with activated prothrombin complex concentrate, there’s a risk of thrombotic microangiopathy and thrombotic events. Full prescribing information can be found on the FDA website.