The FDA has expanded the label for Pfizer’s subcutaneous hemophilia drug Hympavzi, now including patients age 6 and older who have hemophilia A or B.
The anti-tissue factor pathway inhibitor was initially approved in October of 2024 for those age 12 and older with hemophilia A or B who have not developed the antibodies—also known as inhibitors—produced by the immune system that block or destroy infused clotting factor medications.
The new expansion covers all patients 6 and older, regardless of their inhibitor status. The new nod also opens up the treatment to those 12 and older who have developed the inhibitors.
Hympavzi, which is the first hemophilia medicine administered by way of a pre-filled, auto-injector pen, is administered weekly and is used as a prophylactic to reduce the risk of the painful bleeding episodes that accompany the disorder.
“For children who have to deal with bleeding episodes from an early age and for people living with hemophilia who develop inhibitors, treatment options have been limited and are often burdensome,” Guy Young, M.D., the Director of the Hemostasis and Thrombosis Center at Children’s Hospital in Los Angeles, said in a release.
Hympavzi provides control with “a level of simplicity this community has long needed,” Young added.
Hemophilia, which prevents blood from clotting properly and can include painful bleeding in the joints, impacts more than 800,000 people worldwide, Pfizer said. Childrens’ joints have growing cartilage and bone, which makes them particularly susceptible to damage caused by the bleeding episodes, the company added.
Inhibitor antibodies develop in roughly 20% of those with hemophilia A and 3% of those with hemophilia B and are associated with an increased risk of uncontrolled bleeding. Factor replacement therapies can become ineffective in those who are classified as inhibitors.
The phase 3 Basis trial backed the approval of Hympavzi as a treatment for those age 12 and older with inhibitors, showing a 93% reduction in the annualized bleeding rate after patients switched from prior regimens. In the phase 3 Basis Kids trial, which included patients ages 6 to 17, annualized bleeding rates were also significantly reduced for those with and without inhibitors.
Pfizer did not break out sales of Hympavzi in its first-quarter earnings report.
Hympavzi was one of two hemophilia treatments Pfizer gained approval for in 2024. The other was hemophilia B gene therapy Beqvev, which was priced at $3.5 million and was removed from the market in February of last year after it failed to drum up much interest from patients or doctors.
Roche’s Hemlibra is the top-selling branded hemophilia drug on the market, generating sales of 4.5 billion Swiss francs ($5.7 billion) last year. It is for those who have hemophilia A.
Novo Nordisk’s once-daily subcutaneous Alhemo, for patients with hemophilia A or B, was approved in 2024. Last year, Sanofi and Alnylam gained FDA approval for Qfitlia, which is administered subcutaneously every one or two months and can be used by those with either type of hemophilia and regardless of inhibitor status.