FDA Grants Breakthrough Therapy Designation for Hemophilia A Treatment

Today, Genentech announced that the US Food and Drug Administration (FDA) granted Breakthrough Therapy Designation to emicizumab-kxwh (Hemlibra) for people with hemophilia A without factor VIII inhibitors.

Hemlibra (emicizumab-kxwh) is a bispecific factor IXa- and factor X-directed antibody that is engineered to combine factor IXa and factor X, which are proteins required to activate the natural coagulation cascade and restore the blood clotting process for hemophilia A patients.

Hemophilia A is an inherited and serious disorder; it causes the blood to clot improperly, which consequently leads to uncontrolled and spontaneous bleeding. Hemlibra can be administered once weekly by an injection of a ready-to-use solution under the skin (subcutaneously); it is a prophylactic (preventative) treatment.

“Hemlibra is the first medicine to show superior efficacy compared to factor VIII prophylaxis, the standard of care for people with hemophilia A without inhibitors, in an intra-patient comparison,” said Sandra Horning, MD, chief medical officer and head of Global Product Development at Genentech. “We look forward to working with health authorities to make Hemlibra available to people without inhibitors as soon as possible, and we are excited to share this news with the community as we join in celebrating World Hemophilia Day.”¹

The FDA’s designation is based on data from the Phase III HAVEN 3 study in people aged 12 years or older with hemophilia A without inhibitors. HAVEN 3 is a randomized, multicenter, open-label, Phase III study that is aimed at evaluating the efficacy, safety, and pharmacokinetics of Hemlibra prophylaxis in comparison to no prophylaxis (episodic/on-demand factor VIII treatment) in people with hemophilia A without inhibitors to factor VIII. One hundred and fifty-two patients with hemophilia A (aged 12 years or older) who were previously treated with factor VIII therapy either on-demand or for prophylaxis were included in the study.

Hemlibra prophylaxis, which was dosed subcutaneously every week or every two weeks, showed a statistically significant and clinically meaningful reduction in treated bleeds compared to no prophylaxis. Once-weekly Hemlibra prophylaxis was superior to prior factor VIII prophylaxis as demonstrated by a statistically significant and clinically meaningful reduction in treated bleeds in an intra-patient comparison.

Injection site reactions were the most common adverse events with Hemlibra, and no new safety signals were observed. Neither thrombotic microangiopathy nor thrombotic events occurred in this study.

Patients previously treated with on-demand factor VIII were randomized in a 2:2:1 fashion to receive subcutaneous Hemlibra prophylaxis at 3 mg/kg/wk for 4 weeks, followed by 1.5 mg/kg/wk until the end of study (Arm A), subcutaneous Hemlibra prophylaxis at 3 mg/kg/wk for 4 weeks, followed by 3 mg/kg/2wks until the end of study (Arm B), or no prophylaxis (Arm C). Patients previously treated with factor VIII prophylaxis received subcutaneous Hemlibra prophylaxis at 3 mg/kg/wk for 4 weeks, followed by 1.5 mg/kg/wk until the end of study (Arm D). Breakthrough bleeds were treated as episodic treatments with factor VIII therapy, which was allowed per protocol.

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References:

1. FDA Grants Breakthrough Therapy Designation for Genentech’s Hemlibra (emicizumab-kxwh) in Hemophilia a Without Inhibitors. https://www.businesswire.com/news/home/20180416006631/en/FDA-Grants-Breakthrough-Therapy-Designation-Genentech%E2%80%99s-Hemlibra. Accessed April 17, 2018.