Fidanacogene elaparvovec

“Based on the current knowledge and the overall clinical data collected to date across multiple studies and real-world data, Pfizer does not anticipate any impact to safety for patients treated with approved marstacimab,” a Pfizer spokesperson told Fierce, using Hympavzi's generic name. A patient in an open label extension study of Pfizer’s hemophilia treatment Hympavzi has died, the company and several hemophilia advocacy groups confirmed this week.Pfizer is now working with its trial investigator and independent data monitoring committee to accrue more information and better understand the circumstances behind the incident, the New York drugmaker wrote in a letter to the hemophilia community, which was posted online (PDF) by the World Federation of Hemophilia (WFH) on Dec. 22.Pfizer also sent a copy of the letter to Fierce.In a Monday press release, WFH and the National Bleeding Disorders Foundation (NBDF) said Pfizer had informed them that the “severe adverse event” occurred Dec. 14. Specifically, a patient on prophylaxis with Hympavzi (marstacimab) “suffered a fatal thrombotic stroke after minor surgery,” the organizations wrote.The patient had hemophilia A and active inhibitors—antibodies that are known to attack infused clotting factor drugs—Pfizer noted in its letter. That said, Hympavzi is not a clotting factor, but rather an anti-tissue factor pathway inhibitor.The patient had been a participant in the active treatment phase of Pfizer’s Hympavzi parent study in 2022 before switching over to the long-term extension trial in 2023, Pfizer said. The open-label extension trial is assessing Hympavzi in hemophilia patients with or without inhibitors, according to the U.S.’ online clinical trial repository.The company added that it has informed regulators and investigators of the death. “The safety and well-being of participants in our clinical trials remain our highest priority, and we are committed to transparency and keeping the community informed as we learn more,” Pfizer wrote. “Pfizer, together with the trial investigator and the independent external Data Monitoring Committee, are actively gathering information to better understand the complex, multi-factorial circumstances surrounding this occurrence – including co-existing conditions and concomitant medications – and the causality of the event,” a Pfizer spokesperson told Fierce in an emailed statement.“Based on the current knowledge and the overall clinical data collected to date across multiple studies and real-world data, Pfizer does not anticipate any impact to safety for patients treated with approved marstacimab,” the spokesperson added. Patients taking Hympavzi should continue to be managed according to their doctor’s judgment, the Pfizer representative added. The treatment is not currently approved to treat hemophilia with inhibitors, the WFH and the NBDF pointed out in their release.While a causal link between the death and Pfizer’s drug has not been drawn at this time, thrombosis is an “adverse event of special interest” with Hympavzi given the drug’s mechanism of action as a rebalancing agent that targets tissue factor pathway inhibitor to increase thrombin generation for clot formation, the hemophilia advocacy groups explained.Thrombotic events have been recorded with other nonfactor hemohpilia therapies, the WFH and the NBDF noted. Hympavzi was one of two hemophilia approvals Pfizer won in 2024, with the other being for its now-discontinued gene therapy Beqvez.For its part, Hympavzi was cleared by the FDA last October to treat patients ages 12 and older with hemophilia A or B who haven’t developed antibodies to previous inhibitor treatments. The drug was subsequently greenlit in the EU in November 2024 and has also picked up approvals in places like the U.K. and Switzerland.

iStock, Alexandros Michailidis 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.