In the late-stage trial, the prophylactic treatment with marstacimab showed a statistically significant and clinically relevant reduction in annualised bleeding rate in people with haemophilia A and B
Marstacimab reduced annualised bleeding rate in a phase 3 trial. (Credit: National Cancer Institute on Unsplash)
Pfizer announced that marstacimab has met its primary endpoints, showing statically significant and clinically meaningful effects in Phase 3 BASIS clinical trial of patients with haemophilia A and B.
Marstacimab is an investigational anti-tissue factor pathway inhibitor (anti-TFPI). It is a human monoclonal immunoglobulin G isotype, subclass 1 (IgG1) that targets the Kunitz 2 domain of TFPI.
It is being studied in a Phase 3 open-label, multicentre study for the treatment of haemophilia A or B for people without inhibitors to Factor VIII (FVIII) or Factor IX (FIX).
In the trial, the prophylactic treatment with marstacimab showed a statistically significant and clinically relevant reduction in annualised bleeding rate (ABR) in people living with severe haemophilia A and moderately severe to severe haemophilia B without inhibitors.
The late-stage BASIS trial includes the treatment of 116 people living with haemophilia with marstacimab during a 12-month period versus a prophylaxis and on-demand intravenous regimen with FVIII or FIX, administered as usual care in the six-month lead-in period.
The pharma major said that patients treated with on-demand factor replacement intravenous therapy witnessed a 92% reduction in bleeds.
Additionally, the findings demonstrated superiority with the anti-TFPI compared to prophylaxis, with a 35% reduction in ABR.
Pfizer Global Product Development Oncology and Rare Disease chief development officer Chris Boshoff said: “These results support the potential for marstacimab to become the first once-weekly non-factor treatment for people with haemophilia B and a treatment option that helps address the diverse needs of patients with haemophilia A or B without inhibitors.
“These needs include preventing excessive or potentially life-threatening bleeds, while at the same time reducing the burden of treatment with once-weekly, subcutaneous administration.”
BASIS trial assessed annualised bleed rate through 12 months on treatment with marstacimab in around 145 participants between ages 12 to <75 years.
The participants were dosed with flat dosing in the trial as a subcutaneous 300 mg loading dose of the anti-TFPI followed by 150 mg once weekly.
In addition, the pharma company is conducting a BASIS KIDS study to assess the safety and efficacy of marstacimab in children less than eight years of age with haemophilia A and B.