The patient, who died on December 14, was originally enrolled in a Phase III study in 2022 and transitioned into an extension phase in 2023.
A patient taking Pfizer’s approved hemophilia A therapy Hympavzi has died, the New York pharma disclosed Monday.
The patient had been participating in a long-term follow up clinical trial featuring Hympavzi, which was approved in October 2024 for patients with hemophilia A or B without inhibitors. Pfizer revealed the death in a letter to patient communities.
The death occurred on December 14. The patient was originally enrolled in a Phase III study that occurred in 2022 and transitioned into an extension phase in 2023. They continued to receive Hympavzi as a prophylaxis plus recombinant factor VIIa to prevent bleeding after a minor surgery. The patient experienced serious adverse events including a stroke and bleeding in the brain.
Pfizer said it is working with the data monitoring committee to gather information about the death. The company noted co-existing medical conditions and other medications the patient was taking at the time.
Hympavzi was approved in the U.S. in October 2024 as a once-weekly subcutaneous prophylactic injection for hemophilia A or B. It has since been granted authorization in Europe.
The therapy is an IgG1 monoclonal antibody that targets the Kunitz domain 2 of the tissue factor pathway inhibitor protein, which prevents blood clotting. This mechanism of action allows Hympavzi to enhance coagulation in hemophilia patients.
Earlier this year, Pfizer discontinued the hemophilia gene therapy Beqvez in all global markets, citing low patient interest and a shift to Hympavzi. Pfizer partnered with Sangamo Therapeutics on Beqvez.
In September 2024, Pfizer pulled the sickle cell disease therapy Oxbryta from the market after new data showed a higher risk of death and complications in patients who received it.
