Prevymis – SSI*
Prevymis – SSI* (Tablets)
Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1 in the PI. Concomitant administration with pimozide. Concomitant administration with ergot alkaloids. Concomitant administration with St. John’s wort (Hypericum perforatum). When letermovir is combined with cyclosporine. Concomitant use of dabigatran, atorvastatin, simvastatin, rosuvastatin or pitavastatin is contraindicated.
Precautions/warning
Monitoring of CMV DNA: The safety and efficacy of letermovir has been established in HSCT 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. Risk of adverse reactions or reduced therapeutic effect due to medicinal product interactions: The concomitant use of letermovir 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. Drug interactions: Letermovir 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. Increased monitoring of cyclosporine, tacrolimus, sirolimus is generally recommended the first 2 weeks after initiating and ending 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. 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 section 4.5 and Table 1). 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’.
Adverse reactions
The safety assessment of letermovir was based on two Phase 3 clinical trials. In P001 adult HSCT recipients received letermovir or placebo through Week 14 post-transplant and were followed for safety through Week 24 post-transplant. The most commonly reported adverse reactions occurring in at least 1% of subjects in the letermovir group and at a frequency greater than placebo were: nausea (7.2%), diarrhea (2.4%), and vomiting (1.9%).The most frequently reported adverse reactions that led to discontinuation of letermovir were nausea (1.6%), vomiting (0.8%), and abdominal pain (0.5%). In P040 adult HSCT recipients received letermovir or placebo from Week 14 (~100 days) through Week 28 (~200 days) post-HSCT and were followed for safety through Week 48 post-HSCT. The adverse reactions reported were consistent with the safety profile of letermovir as characterised in study P001. The following adverse reactions were identified in patients taking letermovir in clinical trials: The very common and common adverse reactions were nausea, diarrhea, vomiting. Additional adverse reactions identified with letermovir: dysgeusia, headache, vertigo, fatigue, and increased liver enzymes (ALT/AST), as well as muscle spasms, abdominal pain, hypersensitivity, decreased appetite, peripheral oedema and increased creatinine. The safety assessment of letermovir in paediatric patients from birth up to 18 years old was based on a Phase 2b clinical trial (P030). In P030, paediatric HSCT recipients were treated with letermovir through Week 14 post-HSCT. The adverse reactions were consistent with those observed in clinical studies of letermovir in adults.
*For the full information please see the Prescribing Information as approved by the MoH in January 2026
Prevymis – SSI* (oral granules)
Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1 in the PI. Concomitant administration with pimozide. Concomitant administration with ergot alkaloids. Concomitant administration with St. John’s wort (Hypericum perforatum). When letermovir is combined with cyclosporine. Concomitant use of dabigatran, atorvastatin, simvastatin, rosuvastatin or pitavastatin is contraindicated.
Precautions/Warning
Monitoring of CMV DNA: The safety and efficacy of letermovir has been established in HSCT 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. Risk of adverse reactions or reduced therapeutic effect due to medicinal product interactions: The concomitant use of letermovir 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. Drug interactions: Letermovir 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. Increased monitoring of cyclosporine, tacrolimus, sirolimus is generally recommended the first 2 weeks after initiating and ending 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. 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 section 4.5 and Table 1). 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’.
Adverse Reactions
The safety assessment of letermovir was based on two Phase 3 clinical trials. In P001 adult HSCT recipients received letermovir or placebo through Week 14 post-transplant and were followed for safety through Week 24 post-transplant. The most commonly reported adverse reactions occurring in at least 1% of subjects in the letermovir group and at a frequency greater than placebo were: nausea (7.2%), diarrhea (2.4%), and vomiting (1.9%).The most frequently reported adverse reactions that led to discontinuation of letermovir were nausea (1.6%), vomiting (0.8%), and abdominal pain (0.5%). In P040 adult HSCT recipients received letermovir or placebo from Week 14 (~100 days) through Week 28 (~200 days) post-HSCT and were followed for safety through Week 48 post-HSCT. The adverse reactions reported were consistent with the safety profile of letermovir as characterised in study P001. The following adverse reactions were identified in patients taking letermovir in clinical trials: The very common and common adverse reactions were nausea, diarrhea, vomiting. Additional adverse reactions identified with letermovir: dysgeusia, headache, vertigo, fatigue, and increased liver enzymes (ALT/AST), as well as muscle spasms, abdominal pain, hypersensitivity, decreased appetite, peripheral oedema and increased creatinine. The safety assessment of letermovir in paediatric patients from birth up to 18 years old was based on a Phase 2b clinical trial (P030). In P030, paediatric HSCT recipients were treated with letermovir through Week 14 post-HSCT. The adverse reactions were consistent with those observed in clinical studies of letermovir in adults.
*For the full information please see the Prescribing Information as approved by the MoH in January 2026