Pfizer Advances Marstacimab, an Anti-TFPI Monoclonal Antibody, into Phase 3 Clinical Development for Hemophilia A and B

November 27, 2020 News /BioValleyBIOON/ --Pfizer(Pfizer) recently announced that the first patient has been dosed in the Phase 3 BASIS study evaluating marstacimab (PF-06741086) for the treatment of hemophilia. Marstacimab is an anti-tissue factor pathway inhibitor (anti-TFPI) administered via subcutaneous injection and is currently under development for the treatment of patients with severe hemophilia A and hemophilia B, regardless of inhibitor status.

BASIS is a global, open-label, multicenter Phase 3 study to be conducted in 145 adolescent and adult patients (aged 12 to <75 years) with severe hemophilia A or B (defined as factor VIII or factor IX activity <1%), regardless of inhibitor status. The study will evaluate the annualized bleeding rate (ABR) over 12 months of prophylactic treatment with marstacimab.

Marstacimab is a human monoclonal immunoglobulin IgG1 that targets the Kunitz domain of tissue factor pathway inhibitor (TFPI). It was developed as a prophylactic treatment to prevent or reduce the frequency of bleeding episodes in patients with severe hemophilia A and hemophilia B. In September 2019, the United StatesFDAMarstacimab has been granted Fast Track Designation (FTD) for the treatment of hemophilia A and hemophilia B.

Results from the completed Phase 2 study demonstrated that marstacimab treatment significantly reduced the annualized bleeding rate (ABR) by >75% in all patients. These patients were monitored in a long-term extension study, which showed sustained efficacy for up to 12 months in 20 patients receiving weekly subcutaneous doses of marstacimab equal to or higher than those used in the Phase 3 BASIS study (a 300 mg subcutaneous loading dose followed by 150 mg subcutaneously once weekly), with no thrombotic events or treatment-related serious adverse events reported.

Brenda Cooperstone, Chief Development Officer of Global Product Development for Pfizer Rare Disease, stated, “Our approach to hemophilia research involves investigating multiple mechanisms to help meet the needs of all patients with hemophilia, including those with hemophilia A and B, both with and without inhibitors. Targeting tissue factor pathway inhibitor (TFPI) offers a novel approach to improving blood coagulation. Based on the Phase 2 study results to date, marstacimab has the potential to improve bleeding control via subcutaneous injection and may eliminate the need for prophylactic factor replacement therapy, providing an enhanced treatment option compared to factor replacement therapy.”(Bio Valley Bioon.com)

Original Source: Pfizer Doses First Participant in Phase 3 Study Evaluating anti-TFPI Investigational Therapy, Marstacimab, for People With Severe Hemophilia A and B With or Without Inhibitors