Prevymis

Name: Prevymis

Adverse Reactions

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adult CMV-seropositive Recipients [R+] of an Allogeneic HSCT

The safety of Prevymis was evaluated in one Phase 3 randomized, double-blind, placebo-controlled trial (P001) in which 565 subjects were randomized and treated with Prevymis (N=373) or placebo (N=192) through Week 14 post-transplant. Adverse events were those reported while subjects were on study medication or within two weeks of study medication completion/discontinuation. The mean time for reporting adverse events and laboratory abnormalities was approximately 22% longer in the Prevymis arm compared to the placebo arm.

Cardiac Adverse Events:

The cardiac adverse event rate (regardless of investigator-assessed causality) was higher in subjects receiving Prevymis (13%) compared to subjects receiving placebo (6%). The most common cardiac adverse events were tachycardia (reported in 4% of Prevymis subjects and in 2% of placebo subjects) and atrial fibrillation (reported in 3% of Prevymis subjects and in 1% of placebo subjects). Among those subjects who experienced one or more cardiac adverse events, 85% of Prevymis and 92% of placebo subjects had events reported as mild or moderate in severity.

Common Adverse Events

The rate of adverse events occurring in at least 10% of subjects in the Prevymis group and at a frequency at least 2% greater than placebo are outlined in Table 1.

Table 1: Trial P001 All Grade Adverse Events Reported in ≥ 10% of Prevymis-Treated HSCT Recipients at a Frequency at least 2% Greater than Placebo
Adverse Events Prevymis
(N=373)
Placebo
(N=192)
nausea 27% 23%
diarrhea 26% 24%
vomiting 19% 14%
peripheral edema 14% 9%
cough 14% 10%
headache 14% 9%
fatigue 13% 11%
abdominal pain 12% 9%

Overall, similar proportions of subjects in each group discontinued study medication due to an adverse event (13% of Prevymis subjects vs. 12% of placebo subjects). The most frequently reported adverse event that led to study drug discontinuation was nausea, occurring in 2% of Prevymis subjects and 1% of placebo subjects. Hypersensitivity reaction, with associated moderate dyspnea, occurred in one subject following the first infusion of IV Prevymis after switching from oral Prevymis, leading to treatment discontinuation.

Laboratory Abnormalities

Selected laboratory abnormalities reported during treatment or within 2 weeks of stopping treatment are presented in the table below.

Table 2: Trial P001 Selected Laboratory Abnormalities
Prevymis
N=373
Placebo
N=192
Absolute neutrophil count (cells/μL)
  < 500 19% 19%
  500 – < 750 4% 7%
  750 – < 1000 8% 9%
Hemoglobin (g/dL)
  < 6.5 2% 1%
  6.5 – < 8.0 14% 15%
  8.0 – < 9.5 41% 43%
Platelets (cells/μL)
  < 25000 27% 21%
  25000 – < 50000 17% 18%
  50000 – < 100000 20% 30%
Serum creatinine (mg/dL)
  > 2.5 2% 3%
  > 1.5 – 2.5 17% 20%

The median time to engraftment (defined as absolute neutrophil count ≥ 500/mm3 on 3 consecutive days after transplantation) was 19 days in the Prevymis group and 18 days in the placebo group.

Prevymis - Clinical Pharmacology

Mechanism of Action

Prevymis is an antiviral drug against CMV [see Microbiology (12.4)].

Pharmacodynamics

Cardiac Electrophysiology

In a thorough QT trial in healthy subjects, letermovir at the therapeutic IV dose or at a dose of 2 times the approved IV dose did not prolong QTc to any clinically relevant extent.

Pharmacokinetics

The pharmacokinetic properties of letermovir are displayed in Table 4.

Table 4: Absorption, Distribution, Metabolism, Elimination (ADME), and Pharmacokinetic Properties of Prevymis*
* Values were obtained in studies of healthy subjects unless otherwise indicated. † Based on geometric mean data. ‡ Values refer to geometric mean ratio [fed/fasted] percentage and 90% confidence interval back transformed from linear mixed-effects model performed on natural log-transformed values. The meal administered was a standard high fat and high calorie meal (33 grams protein, 65 grams carbohydrates, 58 grams fat; 920 total calories). § Single oral administration of radiolabeled letermovir in mass balance study.
Pharmacokinetics in HSCT Recipients
Treatment Regimen Steady-state median (90% prediction interval) AUC (ng∙hr/mL) of Prevymis
  480 mg oral once daily, no cyclosporine 34,400 (16,900, 73,700)
  480 mg IV once daily, no cyclosporine 100,000 (65,300, 148,000)
  240 mg oral once daily, with cyclosporine 60,800 (28,700, 122,000)
  240 mg IV once daily, with cyclosporine 70,300 (46,200, 106,000)
Pharmacokinetics in Healthy Subjects
Treatment Regimen Steady-state geometric mean AUC and Cmax of Prevymis
  480 mg oral once daily Cmax: 13,000 ng/mL
AUC: 71,500 ng∙hr/mL
Dose proportionality Greater than proportional following single and multiple oral or IV doses of Prevymis 240 mg and 480 mg
Accumulation ratio† Cmax: 1.03
AUC: 1.22
Time to steady-state 9-10 days
Absorption
Bioavailability Healthy subjects administered Prevymis without cyclosporine: 94% at an oral dose range of 240 mg to 480 mg
HSCT recipients administered Prevymis without cyclosporine: 35% with 480 mg oral once daily
HSCT recipients administered Prevymis with cyclosporine: 85% with 240 mg oral once daily
Median Tmax (hr) 45 min to 2.25 hr
Effect of food (relative to fasting) ‡ AUC: 99.63% [84.27% - 117.80%]
Cmax: 129.82% [104.35% -161.50%]
Distribution
Mean steady-state volume of distribution 45.5 L following IV administration in HSCT recipients
% In vitro bound to human plasma proteins 99% across the concentration range of 0.2 to 50 mg/L
In vitro blood-to plasma ratio 0.56 across the concentration range of 0.1 to 10 mg/L
Metabolism
In vitro metabolism UGT1A1/1A3 (minor)
Drug-related component in plasma 97% unchanged parent
No major metabolites detected in plasma
Elimination
Route of elimination Hepatic uptake (OATP1B1/3)
Mean terminal t1/2 (hr) 12 hrs after dosing of Prevymis 480 mg IV once daily
% of dose excreted in feces§ 93%
% of dose excreted in urine§ <2%
% of unchanged drug excreted in feces§ 70%

Specific Populations

Pediatric Population

The pharmacokinetics of letermovir in patients less than 18 years of age have not been evaluated.

Age, Gender, Race, and Weight

Age (18 to 78 years), gender, race (White vs. non-White), and body weight (up to 100 kg) did not have a clinically significant effect on the pharmacokinetics of letermovir.

Renal Impairment

Letermovir AUC was approximately 1.9- and 1.4-fold higher in subjects with moderate (eGFR greater than or equal to 30 to 59 mL/min/1.73m2) and severe (eGFR less than 30 mL/min/1.73m2) renal impairment, respectively, compared to healthy subjects.

Hydroxypropyl betadex present in the intravenous letermovir formulation is mainly eliminated by glomerular filtration. Decreased elimination of hydroxypropyl betadex has been reported in the literature in patients with severe renal impairment.

Hepatic Impairment

Letermovir AUC was approximately 1.6- and 3.8-fold higher in subjects with moderate (Child-Pugh Class B [CP-B], score of 7-9) and severe (Child-Pugh Class C [CP-C], score of 10-15) hepatic impairment, respectively, compared to healthy subjects.

Drug Interaction Studies

Drug interaction studies were performed in healthy subjects with Prevymis and drugs likely to be co-administered or drugs commonly used as probes for pharmacokinetic interactions (see Table 5 and Table 6).

In vitro results indicate that letermovir is a substrate of drug metabolizing enzymes CYP3A, CYP2D6, UGT1A1, and UGT1A3, and transporters OATP1B1/3 and P-gp. Oxidative metabolism is considered to be a minor elimination pathway based on in vivo human data. Inhibitors of OATP1B1/3 may result in increases in letermovir plasma concentrations. Changes in letermovir plasma concentrations due to inhibition of P-gp or UGTs are not anticipated to be clinically relevant.

Based on in vitro studies, the metabolism of letermovir is not mediated by CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP2E1, CYP4A11, UGT1A4, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2B4, UGT2B7, UGT2B15, or UGT2B17. The transport of letermovir is not mediated by OATP2B1, OCT1, OAT1, BCRP, or MRP2 in vitro.

Letermovir is a time-dependent inhibitor and inducer of CYP3A in vitro. Co-administration of Prevymis with midazolam resulted in increased exposure of midazolam, indicating that the net effect of letermovir on CYP3A is moderate inhibition (see Table 6). Based on these results, co-administration of Prevymis with CYP3A substrates may increase the plasma concentrations of the CYP3A substrates [see Contraindications (4), Warnings and Precautions (5.1), Drug Interactions (7.2, 7.3), and Table 3]. Letermovir is a reversible inhibitor of CYP2C8 in vitro. When co-administered with Prevymis, plasma concentrations of CYP2C8 substrates are predicted to be increased [see Table 3 in Drug Interactions (7.3)]. Co-administration of Prevymis reduced the exposure of voriconazole, most likely due to the induction of voriconazole elimination pathways, CYP2C9 and CYP2C19. Co-administration of Prevymis with CYP2C9 and CYP2C19 substrates may decrease the plasma concentrations of the CYP2C9 and CYP2C19 substrates [see Table 3 in Drug Interactions (7.3)]. Letermovir is an inducer of CYP2B6 in vitro; the clinical relevance is unknown.

Letermovir inhibited efflux transporters P-gp, breast cancer resistance protein (BCRP), bile salt export pump (BSEP), multidrug resistance-associated protein 2 (MRP2), OAT3, and hepatic uptake transporter OATP1B1/3 in vitro. Co-administration of Prevymis with substrates of OATP1B1/3 transporters (e.g. atorvastatin, a known substrate of CYP3A, OATP1B1/3, and potentially BCRP) may result in a clinically relevant increase in plasma concentrations of OATP1B1/3 substrates [see Table 3 in Drug Interactions (7.3)]. There were no clinically relevant changes in plasma concentrations of digoxin, a P-gp substrate, or acyclovir, an OAT3 substrate, following co-administration with Prevymis in clinical studies (see Table 6). The effect of letermovir on BCRP, BSEP, and MRP2 substrates was not evaluated in clinical studies; the clinical relevance is unknown.

Based on in vitro results letermovir is not an inhibitor of CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, UGT1A4, UGT1A6, UGT1A9, or UGT2B7 and is not an inducer of CYP1A2. Letermovir is not an inhibitor of MRP2, OATP2B1, BSEP, OCT1, OCT2, or OAT1 in vitro.

Table 5: Drug Interactions: Changes in Pharmacokinetics of Letermovir in the Presence of Co-administered Drug
Co-administered Drug Regimen of Co-administered Drug Letermovir Regimen Geometric Mean Ratio [90% CI] of Letermovir PK with/without Co-administered Drug
(No Effect=1.00)
AUC Cmax C24hr*
Abbreviations: PO= oral
* C12hr for tacrolimus
Immunosuppressants
cyclosporine 200 mg single dose PO 240 mg once daily PO 2.11
(1.97, 2.26)
1.48
(1.33, 1.65)
2.06
(1.81, 2.35)
mycophenolate mofetil 1 g single dose PO 480 mg once daily PO 1.18
(1.04, 1.32)
1.11
(0.93, 1.34)
1.39
(1.12, 1.74)
tacrolimus 5 mg single dose PO 80 mg twice daily PO 1.02
(0.97, 1.07)
0.92
(0.84, 1.00)
1.02
(0.93, 1.12)
Table 6: Drug Interactions: Changes in Pharmacokinetics for Co-administered Drug in the Presence of Letermovir
Co-administered Drug Regimen of Co-administered Drug Letermovir Regimen Geometric Mean Ratio [90% CI] of Co-administered Drug PK with/without Letermovir
(No Effect=1.00)
AUC Cmax C24hr*
Abbreviations: PO=oral
* C12hr reported for voriconazole.
CYP3A Substrates
midazolam 1 mg single dose IV 240 mg once daily PO 1.47
(1.37, 1.58)
1.05
(0.94, 1.17)
2.74
(2.16, 3.49)
2 mg single dose PO 240 mg once daily PO 2.25
(2.04, 2.49)
1.72
(1.54, 1.92)
Not available
P-gp Substrates
digoxin 0.5 mg single dose PO 240 mg twice daily PO 0.88
(0.80, 0.96)
0.75
(0.63, 0.89)
0.90
(0.84, 0.96)
Immunosuppressants
cyclosporine 50 mg single dose PO 240 mg once daily PO 1.66
(1.51, 1.82)
1.08
(0.97, 1.19)
2.19
(1.80, 2.66)
mycophenolate mofetil 1 g single dose PO 480 mg once daily PO 1.08
(0.97, 1.20)
0.96
(0.82, 1.12)
1.04
(0.86, 1.27)
tacrolimus 5 mg single dose PO 480 mg once daily PO 2.42
(2.04, 2.88)
1.57
(1.32, 1.86)
2.53
(2.12, 3.03)
sirolimus 2 mg single dose PO 480 mg once daily PO 3.40
(3.01, 3.85)
2.76
(2.48, 3.06)
3.15
(2.80, 3.55)
Antifungals and Antivirals
acyclovir 400 mg single dose PO 480 mg once daily PO 1.02
(0.87, 1.2)
0.82
(0.71, 0.93)
1.13
(0.94, 1.36)
posaconazole 300 mg single dose PO 480 mg once daily PO 0.98
(0.82, 1.17)
1.11
(0.95, 1.29)
1.10
(0.94, 1.30)
voriconazole 200 mg twice daily PO 480 mg once daily PO 0.56
(0.51, 0.62)
0.61
(0.53, 0.71)
0.49
(0.42, 0.57)
HMG-CoA Reductase Inhibitors
atorvastatin 20 mg single dose PO 480 mg once daily PO 3.29
(2.84, 3.82)
2.17
(1.76, 2.67)
3.62
(2.87, 4.55)
Oral Contraceptives
ethinyl estradiol (EE) /levonorgestrel (LNG) 0.03 mg EE single dose PO 480 mg once daily PO 1.42
(1.32, 1.52)
0.89
(0.83, 0.96)
1.57
(1.45, 1.70)
0.15 mg LNG single dose PO 1.36
(1.30, 1.43)
0.95
(0.86, 1.04)
1.38
(1.32, 1.46)

Microbiology

Mechanism of Action

Letermovir inhibits the CMV DNA terminase complex (pUL51, pUL56, and pUL89) which is required for viral DNA processing and packaging. Biochemical characterization and electron microscopy demonstrated that letermovir affects the production of proper unit length genomes and interferes with virion maturation. Genotypic characterization of virus resistant to letermovir confirmed that letermovir targets the terminase complex.

Antiviral Activity

The median EC50 value of letermovir against a collection of clinical CMV isolates in a cell-culture model of infection was 2.1 nM (range = 0.7 nM to 6.1 nM, n = 74). There was no significant difference in EC50 value by CMV gB genotype (gB1=29; gB2=27; gB3=11; and gB4=3).

Combination Antiviral Activity

No antagonism of the antiviral activity was seen when letermovir was combined with CMV DNA polymerase inhibitors (cidofovir, foscarnet, or ganciclovir).

Viral Resistance

In Cell Culture

CMV mutants with reduced susceptibility to letermovir have been selected in cell culture and the resistance mutations map to UL56. Resistance-associated substitutions occur between amino acid positions pUL56 231 and 369 (V231A/L, V236L/M, E237D, L241P, T244K/R, L257I, F261C/L/S, Y321C, C325F/R/Y, M329T, R369G/M/S). EC50 values for virus expressing these substitutions are 13- to 5,870-fold higher than those for the wild-type reference virus.

In Clinical Studies

In a Phase 2b trial evaluating letermovir or placebo in 131 HSCT recipients, DNA sequence analysis of a select region of UL56 (amino acids 231 to 369) was performed on samples obtained from 12 letermovir-treated subjects who experienced prophylaxis failure and for whom on-treatment samples were available for analysis. One subject had a letermovir resistance substitution, pUL56 V236M.

In a Phase 3 trial (P001), DNA sequence analysis of the entire coding regions of UL56 and UL89 was performed on samples obtained from 28 letermovir-treated subjects who had received at least one dose of study drug and experienced prophylaxis failure and for whom samples were available for analysis. Two subjects were identified as having a letermovir-resistance substitution, pUL56 V236M or C325W. These substitutions were identified from on-treatment samples [see Clinical Studies (14)]. A virus from a third subject who experienced prophylaxis failure had a pUL56 E237G substitution at low frequency (<5%), and while pUL56 E237D was associated with resistance in cell culture, the clinical significance of this substitution at this frequency is unknown.

Cross Resistance

Cross resistance is not likely with drugs outside of this class. Letermovir is fully active against viral populations with substitutions conferring resistance to CMV DNA polymerase inhibitors (cidofovir, foscarnet, and ganciclovir). These DNA polymerase inhibitors are fully active against viral populations with substitutions conferring resistance to letermovir.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis and Mutagenesis

Letermovir was not genotoxic in in vitro or in vivo assays, including microbial mutagenesis assays, chromosomal aberration in Chinese hamster ovary cells, and in an in vivo mouse micronucleus study.

Carcinogenicity studies with letermovir have not been conducted.

Impairment of Fertility

In a fertility and early embryonic development study in rats, no effects of letermovir on female fertility were observed at letermovir exposures (AUC) approximately 5 times higher than human exposure at the RHD.

In male rat fertility studies, decreased fertility associated with irreversible testicular toxicity was observed at ≥180 mg/kg/day (greater than or equal to 3 times the human exposure at the RHD). No fertility or testicular effects were observed at dose levels resulting in letermovir exposures (AUC) similar to human exposure at the RHD [see Nonclinical Toxicology (13.2)].

Animal Toxicology and/or Pharmacology

Testicular toxicity in rats observed at ≥180 mg/kg/day (greater than or equal to 3 times the human exposure at the RHD) was characterized by decreased testis weight, bilateral seminiferous tubular degeneration, decreased sperm count and motility, and resultant decreased male fertility. Male reproductive system toxicities were not observed in either a monkey testicular toxicity study up to 240 mg/kg/day (approximately 2 times higher than human exposure at the RHD), or a general toxicology study in mice up to 250 mg/kg/day (approximately 3 times higher than human exposure at the RHD).

PRINCIPAL DISPLAY PANEL - 240 mg Dose Pack Carton

NDC 0006-3075-02

Prevymis™
(letermovir) tablets

240 mg per tablet

1 tablet a day
28-day supply

Rx only

28 Tablets

This carton contains a total of 28 tablets
packaged within 4 dose packs.
Each dose pack contains 7 blister units
with one tablet per blister unit.

PRINCIPAL DISPLAY PANEL - 12 mL Vial Carton

NDC 0006-5003-01

Prevymis™
(letermovir) Injection

240 mg/12 mL
(20 mg/mL)

For Intravenous Infusion Only

Requires dilution prior to administration.
See Package Insert.

Rx only

Single-dose vial. Discard unused portion.

FDA Approves Prevymis

The U.S. Food and Drug Administration (FDA) has approved Prevymis (letermovir), a CMV DNA terminase complex inhibitor indicated for the prophylaxis of cytomegalovirus (CMV) infection and disease in adult allogeneic hematopoietic stem cell transplant patients.

How should I store Prevymis?

  • Store both the tablets and injection at room temperature between 68°F to 77°F (20°C to 25°C).
  • Store the tablets in the original package until you are ready to take your dose.
  • Store the injection in the original carton to protect from exposure to light.

Keep all medicines out of the reach of children and pets.

General information about the safe and effective use of Prevymis

Medicines are sometimes prescribed for purposes other than those listed in the Patient Information leaflet. Do not use this medicine for a condition for which it was not prescribed. Do not give it to other people, even if they have the same symptoms that you have. It may harm them. You can ask your pharmacist or healthcare provider for information that is written for healthcare professionals.

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Letermovir

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Tablet, Film Coated

240 mg

Prevymis

Merck Sharp & Dohme Corp.

480 mg

Prevymis

Merck Sharp & Dohme Corp.

Parenteral

Injection, for IV infusion

20 mg/1 mL

Prevymis

Merck Sharp & Dohme Corp.

Before Using Prevymis

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of letermovir in children. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of letermovir in the elderly.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Bromocriptine
  • Dihydroergotamine
  • Ergonovine
  • Ergotamine
  • Flibanserin
  • Lomitapide
  • Methylergonovine
  • Methysergide
  • Pimozide
  • Pitavastatin
  • Simvastatin

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acalabrutinib
  • Amiodarone
  • Aprepitant
  • Atorvastatin
  • Bosutinib
  • Brexpiprazole
  • Cilostazol
  • Cobimetinib
  • Cyclosporine
  • Deflazacort
  • Eliglustat
  • Eplerenone
  • Fosaprepitant
  • Fosphenytoin
  • Glyburide
  • Ibrutinib
  • Ivabradine
  • Ivacaftor
  • Lovastatin
  • Lurasidone
  • Naloxegol
  • Neratinib
  • Olaparib
  • Phenytoin
  • Repaglinide
  • Rifampin
  • Rosiglitazone
  • Sirolimus
  • Sonidegib
  • Tacrolimus
  • Tolvaptan
  • Venetoclax
  • Voriconazole
  • Warfarin

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Suvorexant

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Kidney disease, severe—Use with caution. May make this condition worse.
  • Liver disease, severe—Use is not recommended in patients with this condition.

What other information should I know?

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to letermovir.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of letermovir in children. Safety and efficacy have not been established.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Kidney disease, severe—Use with caution. May make this condition worse.
  • Liver disease, severe—Use is not recommended in patients with this condition.

Prevymis Interactions

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Tell your doctor about all your current medicines and any you start or stop using. If you also use cyclosporine, your letermovir dose will need to be adjusted.

Other drugs may interact with letermovir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

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