Pfizer presents results from Phase 3 BASIS clinical trial

Pfizer presented results from the pivotal Phase 3 BASIS clinical trial evaluating marstacimab for the treatment of people with severe hemophilia A and moderately severe to severe hemophilia B without inhibitors to Factor VIII or Factor IX. The results from the BASIS trial demonstrated a statistically significant and clinically meaningful effect on annualized bleeding rate. T In the BASIS trial, 116 people living with hemophilia were treated with marstacimab during a 12-month active treatment period versus a routine prophylaxis and on-demand intravenous regimen with FVIII or FIX, administered as part of usual care in a six-month observational period. Marstacimab, a novel, investigational anti-tissue factor pathway inhibitor was administered weekly with flat (not weight-based) dosing as a subcutaneous 300 mg loading dose followed by 150 mg once weekly. The study found that compared to RP, treatment with marstacimab resulted in a 35.2% mean reduction. Marstacimab significantly reduced ABR by 91.6% compared to OD over 12 months. The mean ABR reductions observed with marstacimab were consistent across hemophilia A and B and age groups for OD and were generally consistent across hemophilia A and B and age groups for RP, with all point estimates for a difference less than 2.5. Following 12 months in the ATP, patients had the option to continue receiving marstacimab in the long-term extension study. In the LTE, a consistent reduction in ABR compared to OD and further numerical reduction compared to RP were observed after up to an additional 16 months of follow-up. In the OD group, superiority of marstacimab was demonstrated across all bleeding-related secondary endpoints – spontaneous bleeds, joint bleeds, target joint bleeds, and total bleeds. In the RP group, marstacimab demonstrated non-inferiority to these secondary efficacy endpoints. Health-related quality of life parameters showed non-significant improvements vs OD therapy and non-inferiority versus RP therapy. The safety profile for marstacimab was consistent with Phase 1/2 results and treatment was generally well-tolerated. No deaths were reported and there have been no thromboembolic events or events of consumptive coagulopathy recorded in hemophilia patients in clinical trials investigating marstacimab. One treatment-related serious adverse event was observed, and one patient discontinued from the trial due to a non-treatment-related SAE.