Hemlibra is an antibody therapy that works by combining factors IX and X of the blood clotting cascade, effectively “replacing” the function of factor VIII, which is lacking in Hemophilia A patients. It is administered via a subcutaneous (under the skin) injection.
The approval of Hemlibra for patients without factor VIII inhibitors follows a previous decision to approve the treatment for Hemophila A patients with factor VIII inhibitors. “Inhibitors” are antibodies against factor VIII that are produced when the body treats externally administered factor VIII as an immunological threat.
Approximately 30% of patients with severe hemophilia A develop these inhibitors, while 3–8% of patients with the mild or moderate forms of the disease do so.
“It is great news that Hemlibra has now received an indication for people with hemophilia A without inhibitors,” Paul Wilton, the president of the Canadian Hemophilia Society, said in a press release.
The decision was based largely on data from two clinical trials: HAVEN 3 (NCT02847637), which included 152 male adults and adolescents with Hemophilia A without factor VIII inhibitors; and HAVEN 4 (NCT03020160), which included 41 male adults and adolescents with Hemophilia A with or without these inhibitors. Both studies monitored patients for 24 weeks.
In particular, the HAVEN 3 results demonstrated that, compared to previous episodic (as needed) or prophylactic (preventive) treatment with factor VIII, prophylactic Hemlibra treatment given every week (at a dose of 1.5 mg/kg) or every two weeks (at 3 mg/kg) reduced the number of treated bleeds in patients by 96% and 97%, respectively. More than half of the Hemlibra-treated patients (on both dosing schedules) had no bleeds at all.
The HAVEN 4 trial demonstrated that Hemlibra also reduced bleeds when given on a four-week dosing schedule (6 mg/kg); more than half of the patients had no bleeds, and 90.2% had fewer than three bleeds.
The Health Canada decision approves Hemlibra at all of these dosing options, that is, weekly, bi-weekly, or every four weeks. (The latter is restricted to adults and adolescents.)
“Based on the research we have seen, we are convinced that a number of Canadians may benefit from this new treatment option,” said Wilton.
Jayson Stoffman, MD, medical director of the Manitoba Bleeding Disorders Program, said, “Hemlibra represents an exciting new option for all patients with Hemophilia A. I look forward to the opportunity to offer my patients something that could have an important impact on their quality of life and hemophilia management.”