Active Ingredient: Marstacimab
Marstacimab is indicated for routine prophylaxis of bleeding episodes in patients 12 years of age and older, weighing at least 35 kg, with severe haemophilia B (congenital factor IX deficiency, FIX <1%) without factor IX inhibitors.
For this indication, competent medicine agencies globally authorize below treatments:
For:
In case that patient weight is ≥ 35 kg, subcutaneous, 300 milligrams marstacimab, one dose, over the duration of 1 week. Afterwards, in case that patient weight is ≥ 35 kg, subcutaneous, 150 milligrams marstacimab, once weekly.
The recommended dose for patients 12 years of age and older, weighing at least 35 kg, is an initial loading dose of 300 mg by subcutaneous injection followed thereafter by 150 mg by subcutaneous injection once weekly, at any time of day.
Marstacimab is intended for long-term prophylactic treatment.
A dose adjustment to 300 mg subcutaneous injection weekly can be considered in patients weighing ≥50 kg when control of bleeding events is judged to be inadequate by the healthcare professional. The maximum weekly dose of 300 mg should not be exceeded.
Additional doses of marstacimab should not be used to treat breakthrough bleeding events.
In acute severe illnesses with increased tissue factor expression, such as infection, sepsis, and crush injuries, potentiation of the inflammatory response via concomitant tissue factor pathway inhibitor (TFPI) inhibition could pose a risk of adverse reactions, especially thrombosis.
Treatment of acute severe illness should be managed per local standard of care, and continued treatment with marstacimab in this situation should be weighed against the potential risks involved. Additional monitoring for adverse reactions and the development of thromboembolism may be warranted in these patients when marstacimab is administered. Marstacimab should be temporarily interrupted if clinical symptoms, imaging, and/or laboratory findings consistent with thrombotic events occur, and managed as clinically indicated. Marstacimab therapy may be resumed once the patient has clinically recovered at the clinical judgement of the healthcare provider (see Missed dose section below).
If a dose is missed, administer as soon as possible before the day of the next scheduled dose, and then resume usual weekly dosing schedule.
If the missed dose is more than 13 days after the last dose, then a loading dose of 300 mg by subcutaneous injection should be administered followed thereafter by a resumption of 150 mg by subcutaneous injection once weekly.
Switching from prophylactic factor replacement therapy to marstacimab: Prior to initiation of marstacimab, patients should discontinue treatment with clotting factor concentrates (factor VIII or factor IX concentrates). Patients can initiate marstacimab at any time after discontinuing clotting factor concentrates.
Switching from non-factor-based haemophilia medicinal products to marstacimab: No clinical study data are available to guide converting patients from non-factor-based medicinal products to marstacimab. Although a washout period has not been studied, one approach is to allow an adequate washout period (at least 5 half-lives) of the prior agent based on labelled half-life before initiating treatment with marstacimab. Haemostatic support with clotting factor concentrates may be needed during the switch from other non-factor-based haemophilia medicinal products to marstacimab.
The recommended injection sites are the abdomen and thigh. Other locations are acceptable if required. Administration of marstacimab in the upper arm (pre-filled syringe only) and buttocks (pre-filled pen only) should be performed by a caregiver or healthcare professional only. The medicinal product should not be administered into bony areas or areas where the skin is bruised, red, tender or hard, or areas where there are scars or stretch marks.
For the 300 mg loading dose, each of the two marstacimab 150 mg injections should be administered at different injection sites.
It is recommended to rotate the injection site with each injection.
Marstacimab should not be injected into a vein or muscle.
During treatment with marstacimab, other medicinal products for subcutaneous administration should, preferably, be injected at different anatomical sites.
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