Patient Dies In Pfizer's Long -term Extension Trial Of Hemophilia Drug

(RTTNews) - Pfizer Inc. (PFE) has announced that a participant in the long-term extension trial evaluating Marstacimab in people living with hemophilia A or B with or without inhibitors has passed away following serious adverse events of cerebellar infarction and subsequent cerebral hemorrhage.

The individual completed the active treatment phase of the parent study, dubbed B7841005, in 2022 and subsequently enrolled in the long-term extension study in 2023.

B7841005 was a phase 3 trial that included adolescents and adults aged 12 to under 75 years with severe hemophilia A or moderately severe to severe hemophilia B, with or without inhibitors, who received prophylactic treatment consisting of subcutaneous Marstacimab Injection.

Marstacimab received approval in the U.S. last October for the treatment of adults and adolescents with hemophilia A or B without inhibitors and is marketed under the brand name Hympavzi. The drug was approved in Europe in November 2024.

Pfizer said that along with the trial investigator and the independent external Data Monitoring Committee, they are actively collecting details to better understand what happened - including the person's co-existing medical conditions, any additional medications and whether the event was related to the study drug.

Early this year, Pfizer discontinued the development and marketing of its FDA-approved hemophilia B gene therapy product Beqvez, citing "limited interest." Unlike Beqvez, Hympavzi is not a gene therapy; instead, it is a rebalancing agent that targets the Kunitz-2 domain of tissue factor pathway inhibitor (TFPI), a natural anticoagulant protein involved in regulating clot formation and restoring hemostasis.

PFE is currently trading at $25.06, down 0.15%.