Pfizer Inc. (NYSE: PFE) today announced that the U.S. Food and Drug Administration (FDA) has accepted the company's Biologics License Application (BLA) for its anti-tissue factor pathway inhibitor (anti-TFPI) candidate marstacimab for individuals living with hemophilia A or hemophilia B without inhibitors to Factor VIII (FVIII) or Factor IX (FIX). The European marketing authorization application (MAA) for marstacimab also passed validation and is currently under review by the European Medicines Agency (EMA).
The FDA has set a Prescription Drug User Fee Act (PDUFA) action date in the fourth quarter of 2024, and a decision from the European Commission is anticipated by the first quarter of 2025. If approved in the U.S. and EU, marstacimab is expected to become the first once-weekly subcutaneous treatment for people living with hemophilia B and the first treatment administered as a flat dose for people living with hemophilia A or B.
"Marstacimab has demonstrated that it may be an efficacious treatment option with once-weekly, subcutaneous flat-dose administration via an auto-injector pen, for appropriate patients, if approved. This is critical as intravenous infusions are typically required for people living with these diseases today," said James Rusnak, M.D., Ph.D., Senior Vice President, Chief Development Officer, Internal Medicine and Infectious Diseases, Research and Development, Pfizer. "We look forward to progressing the review of this novel therapy with the FDA, EMA, and global regulatory authorities to bring this important medicine to patients globally."
For more than five decades, the most common treatment approach for hemophilia A and B has been factor replacement therapy, which replaces missing clotting factors to facilitate proper blood coagulation.i Marstacimab is a novel, investigational treatment for hemophilia that is designed to restore hemostasis by inhibiting TFPI. For appropriate patients living with hemophilia A and B, the goal of this treatment is to prevent potentially life-threatening bleeds with a once-weekly, subcutaneous flat-dose administration.
The submissions for marstacimab are based on efficacy and safety data from the Phase 3 BASIS trial (NCT03938792). Key findings were recently presented at the American Society of Hematology (ASH) Annual Meeting and Exposition on December 9, 2023. The inhibitor cohort of the BASIS trial has completed enrollment and is expected to read out as early as late 2024.
About Marstacimab
Marstacimab is a human monoclonal immunoglobulin G isotype, subclass 1 (IgG1) that targets the Kunitz 2 domain of tissue factor pathway inhibitor (TFPI), a natural anticoagulation protein that functions to prevent the formation of blood clots. Marstacimab is in development as a prophylactic treatment to prevent or reduce the frequency of bleeding episodes in individuals with hemophilia A or hemophilia B with or without inhibitors.
In September 2019, the U.S. FDA granted Fast Track designation to marstacimab for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in hemophilia A with inhibitors or hemophilia B with inhibitors.
Pfizer has three Phase 3 programs investigating treatments for people living with hemophilia: marstacimab, fidanacogene elaparvovec (hemophilia B), and giroctocogene fitelparvovec (hemophilia A).
About the BASIS study
BASIS is a global Phase 3, open-label, multicenter study evaluating annual bleed rate (ABR) through 12 months of treatment with marstacimab, an investigational, novel subcutaneous therapy option, in approximately 145 adolescent and adult participants ages 12 to
Pfizer is also conducting BASIS KIDS, an open-label study investigating the safety and efficacy of marstacimab in children ages 1 to
About Hemophilia
Hemophilia is a family of rare genetic blood diseases caused by a clotting factor deficiency (FVIII in hemophilia A, FIX in hemophilia B), which prevents normal blood clotting. Hemophilia is diagnosed in early childhood and impacts more than 400,000 people worldwide.ii The inability of the blood to clot properly can increase the risk of painful bleeding inside the joints, which can cause joint scarring and damage. People living with hemophilia can suffer permanent joint damage following repeated bleeding episodes.i,ii
For decades, the most common treatment approach for hemophilia A and B has been factor replacement therapy, which replaces the missing clotting factors. Factor replacement therapies increase the amount of clotting factor in the body to levels that improve clotting, resulting in less bleeding.iii,iv Approximately 25-30% of people with hemophilia A and 3-5% of people with hemophilia B are unable to continue taking factor replacement therapies because they develop inhibitors to FVIII and FIX.v,vi
In a survey of people in the U.S. receiving prophylaxis for hemophilia A or B, nearly one-third of those that receive treatment and have high compliance - defined as taking 75% or more of their prescribed infusions - stated that the time-consuming nature of prophylaxis was the most significant challenge of the regimen.vii,viii Nearly 60% of those that took the less than the prescribed number of infusions reported that the time commitment was the primary reason for missing infusions.
