Prevymis Special Precautions

Monitoring of CMV DNA: The safety and efficacy of letermovir has been established in patients with a negative CMV DNA test result prior to initiation of prophylaxis. CMV DNA was monitored on a weekly basis until post-transplant Week 14, and subsequently every two weeks until Week 24. In cases of clinically significant CMV DNAemia or disease, letermovir prophylaxis was stopped and standard-of-care pre-emptive therapy (PET) or treatment was initiated. In patients in whom letermovir prophylaxis was initiated and the baseline CMV DNA test was subsequently found to be positive, prophylaxis could be continued if PET criteria had not been met (see Pharmacology: Pharmacodynamics under Actions).
Risk of adverse reactions or reduced therapeutic effect due to medicinal product interactions: The concomitant use of PREVYMIS and certain medicinal products may result in known or potentially significant medicinal product interactions, some of which may lead to: possible clinically significant adverse reactions from greater exposure of concomitant medicinal products or letermovir; significant decrease of concomitant medicinal product plasma concentrations which may lead to reduced therapeutic effect of the concomitant medicinal product.
See Table 4 for steps to prevent or manage these known or potentially significant medicinal product interactions, including dosing recommendations (see Contraindications and Interactions).
Drug interactions: PREVYMIS should be used with caution with medicinal products that are CYP3A substrates with narrow therapeutic ranges (e.g., alfentanil, fentanyl, and quinidine) as co-administration may result in increases in the plasma concentrations of CYP3A substrates. Close monitoring and/or dose adjustment of co-administered CYP3A substrates is recommended (see Interactions).
Increased monitoring of cyclosporine, tacrolimus, sirolimus is generally recommended the first 2 weeks after initiating and ending letermovir (see Interactions) as well as after changing route of administration of letermovir.
Letermovir is a moderate inducer of enzymes and transporters. Induction may give rise to reduced plasma concentrations of some metabolised and transported medicinal products (see Interactions). Therapeutic drug monitoring (TDM) is therefore recommended for voriconazole. Concomitant use of dabigatran should be avoided due to risk of reduced dabigatran efficacy.
Letermovir may increase the plasma concentrations of medicinal products transported by OATP1B1/3 such as many of the statins (see Interactions and Table 4).
Excipients: PREVYMIS contains lactose monohydrate. Patients with rare hereditary problems of galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should not take this medicinal product.
This medicinal product contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially 'sodium-free'.
Effects on ability to drive and use machines: PREVYMIS may have minor influence on the ability to drive or use machines. Fatigue and vertigo have been reported in some patients during treatment with PREVYMIS, which may influence a patient's ability to drive and use machines (see Adverse Reactions).