FDA Sets Review Date for Marstacimab to Treat Hemophilia

The FDA has accepted Pfizer’s biologics license application (BLA) for marstacimab to treat patients with hemophilia A or B. The FDA has set a Prescription Drug User Fee Act (PDUFA) action date in the fourth quarter of 2024.

Marstacimab is a human monoclonal immunoglobulin G isotype, subclass 1. It targets the tissue factor pathway inhibitor (TFPI), a natural anticoagulation protein that functions to prevent the formation of blood clots. If approved, marstacimab would be indicated to prevent or reduce the frequency of bleeding episodes in people with hemophilia A or hemophilia B with or without inhibitors to factor VIII or factor IX, which are key mechanisms involved in blood clotting.

Hemophilia is a family of rare genetic blood diseases caused by a clotting factor deficiency. A lack of factor VIII leads to hemophilia A, and a lack of factor IX leads to hemophilia B. Hemophilia is diagnosed in early childhood and impacts more than 400,000 people worldwide. About 25% to 30% of people with hemophilia A and 3% to 5% of people with hemophilia B are unable to continue taking factor replacement therapies because they develop inhibitors to factor VIII and factor IX.

The submission for marstacimab is based on data from the phase 3 BASIS trial, which demonstrated a statistically significant and clinically meaningful effect on annualized bleeding rate. The trial enrolled 116 people with hemophilia who were treated with marstacimab compared with those treated with a routine prophylaxis and on-demand intravenous regimen with factor VIII or factor IX.

Compared with routine prophylaxis, treatment with marstacimab resulted in a 35.2% mean reduction in the annualized bleeding rate over 12 months. Compared with on-demand intravenous treatment with Factor VIII or Factor IX, marstacimab significantly reduced annualized bleeding rate over 12 months by 91.6%.

In the long-term extension of the BASIS trial, treatment with marstacimab resulted in consistent reduction in annualized bleeding rate compared with on-demand treatment and routine prophylaxis after up to an additional 16 months of follow-up.

The most common adverse events of patients treated with marstacimab were COVID-19, hemorrhage, hepatic disorder, hypersensitivity, hypertension and injection site reaction. One treatment-related serious adverse event was observed (peripheral swelling), and one patient discontinued from the trial due to a non-treatment-related serious adverse event.

Key findings were recently presented at the American Society of Hematology (ASH) Annual Meeting and Exposition on Dec. 9, 2023.

Davide Matino, M.D.

“Based on these results, marstacimab has shown the potential to address the diverse needs of appropriate patients with hemophilia A or B without inhibitors with weekly subcutaneous administration in a flat dose that is not weight-based, and with low monitoring requirements,” Davide Matino, M.D., M.Sc., assistant professor of Medicine, McMaster University, said in a press release.

Additionally, the European marketing authorization application (MAA) for marstacimab is currently under review by the European Medicines Agency (EMA). A decision from the European Commission is anticipated by the first quarter of 2025.

Pfizer currently has three phase 3 programs in hemophilia, including two therapies: fidanacogene elaparvovec and giroctocogene fitelparvovec.

This story first appeared on Managed Healthcare Executive.