Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Although factor VIII (fVIII) and factor IX (fIX) products are used in clinical practice to treat breakthrough bleeding in patients receiving marstacimab prophylaxis, coadministration with clotting factors may have synergistic effects on thrombin generation and increase the risk of thrombosis. An interaction study in mice demonstrated slightly increased peak thrombin levels when marstacimab was coadministered with recombinant factor VIIa or activated prothrombin, compared to either agent alone. The observed increase was within the reported range for nonhemophilic plasma and did not generate excessive thrombin. Clinical data are not available and the extent to which other coagulation factors may interact with marstacimab is unknown.

MANAGEMENT: Caution and monitoring are recommended with if treatment for breakthrough bleeding is necessary during marstacimab prophylaxis. The manufacturer recommends that if treatment with factor VIII or factor IX is indicated, the minimum effective dose should be considered. Patients should be advised to seek immediate medical attention if they experience signs or symptoms of thromboembolism. In addition, a cautious approach is advised in patients with previous histories of thromboembolic events, as marstacimab has not been studied in these patients.