Recommended Dose: An initial loading dose of 300 mg (two 150 mg injections) is administered subcutaneously on Day 1, followed by a maintenance dose of 150 mg once weekly. For patients weighing 50 kg or more who continue to experience breakthrough bleeding, the maintenance dose may be increased to 300 mg once weekly according to the approved prescribing information.

Time: Administer by subcutaneous injection once weekly on the same day each week. Treatment should be initiated when the patient is not experiencing an active bleeding episode.

Instructions for use: Inject subcutaneously into the abdomen, thigh, or upper arm using the prefilled syringe. Injection sites should be rotated. After appropriate training, patients or caregivers may administer the injections. No dose adjustment is required in patients with mild or moderate hepatic or renal impairment; caution is advised in severe impairment.

Interaction: Marstacimab is not metabolized through the CYP450 enzyme system and has a low potential for drug-drug interactions. Caution is recommended when coagulation factor concentrates are administered concurrently, as thrombotic risk may increase.

Side effects: Common adverse reactions include injection-site reactions, headache, fatigue, upper respiratory tract infection, and arthralgia. Transient elevations in liver enzymes and D-dimer levels have also been reported. The most important safety concern is thromboembolic events, particularly in patients receiving higher maintenance doses.