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Letermovir

Class: Antivirals, Miscellaneous
Chemical Name: 2-[(4S)-8-fluoro-2-[4-(3-methoxyphenyl)piperazin-1-yl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-4H-quinazolin-4-yl]acetic acid
Molecular Formula: C29H28F4N4O4
CAS Number: 917389-32-3
Brands: Prevymis

Medically reviewed by Drugs.com on May 24, 2021. Written by ASHP.

Introduction

Antiviral; DNA terminase complex inhibitor active against cytomegalovirus (CMV).

Uses for Letermovir

Prevention of CMV Infection and Disease

Prophylaxis to prevent CMV infection and disease in adult CMV-seropositive recipients (R+) of an allogeneic hematopoietic stem cell transplant (HSCT). Designated an orphan drug by FDA for prevention of CMV viremia and disease in at-risk populations.

Letermovir Dosage and Administration

Administration

Administer orally or by IV infusion.

Use IV letermovir only in patients unable to receive the drug orally. In those receiving IV letermovir, switch to oral tablet as soon as patient is able to receive oral drugs.

Oral Administration

Administer orally without regard to food. Swallow tablet whole.

IV Administration

For solution and drug compatibility information, see Compatibility under Stability.

Administer by IV infusion through peripheral catheter or central venous line. Do not administer by rapid IV injection.

Available as preservative-free, sterile concentrate for injection that must be diluted prior to IV infusion.

Dilution

The concentrate should appear clear and colorless; do not use if it appears discolored or contains particles.

To prepare a 240- or 480- mg dose, withdraw entire contents of single-dose vial containing 240 or 480 mg, respectively, and add to a 250-mL prefilled IV bag containing either 0.9% sodium chloride injection or 5% dextrose injection. Mix gently; do not shake.

Diluted solution should appear clear and may range from colorless to yellow in color; discard if it contains particles.

Letermovir is compatible only with 0.9% sodium chloride or 5% dextrose; do not dilute using any other infusion fluids.

Must be used with compatible IV bag materials, infusion set materials, plasticizers, and catheters.

Compatible IV bag materials: Polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), polyolefin (polypropylene and polyethylene).

Compatible infusion set materials: PVC, polyethylene (PE), polybutadiene (PBD), silicone rubber (SR), styrene-butadiene copolymer (SBC), styrene-butadiene-styrene copolymer (SBS), polystyrene (PS). Use with polyurethane-containing IV administration set tubing not recommended.

Compatible plasticizers: Diethylhexyl phthalate (DEHP), tris [2-ethylhexyl] trimelliatate (TOTM), benzyl butyl phthalate (BBP).

Compatible catheters: Radiopaque polyurethane.

Rate of Administration

Administer by IV infusion over 1 hour.

Dosage

Adults

Prevention of CMV Infection and Disease
CMV-seropositive Allogeneic HSCT Recipients
Oral or IV

480 mg once daily.

Initiate within 28 days after HSCT (before or after engraftment) and continue through day 100 posttransplantation. Monitor for CMV reactivation after letermovir discontinued.

CMV-seropositive Allogeneic HSCT Recipients Receiving Cyclosporine
Oral or IV

240 mg once daily.

If cyclosporine initiated in patient receiving letermovir 480 mg once daily, decrease letermovir dosage to 240 mg once daily.

If cyclosporine discontinued in patient receiving letermovir 240 mg once daily, increase letermovir dosage to 480 mg once daily.

If cyclosporine regimen interrupted due to high cyclosporine plasma concentrations in a patient receiving letermovir 240 mg once daily, continue same letermovir dosage.

Special Populations

Hepatic Impairment

Oral or IV

Mild or moderate hepatic impairment (Child-Pugh class A or B): Dosage adjustments not needed based on hepatic function.

Severe hepatic impairment (Child-Pugh class C): Not recommended.

Renal Impairment

Oral or IV

Clcr >10 mL/minute: Dosage adjustments not needed based on renal function.

End-stage renal disease (Clcr ≤10 mL/minute), including those receiving dialysis: Data insufficient to make dosage recommendations; safety not known.

IV

Clcr <50 mL/minute: Accumulation of the IV vehicle (i.e., hydroxypropyl betadex) may occur. (See Renal Impairment under Cautions.)

Geriatric Patients

Dosage adjustments based on age not needed.

Cautions for Letermovir

Contraindications

  • Concomitant use with pimozide or ergot alkaloids. (See Interactions.)

  • Concomitant use with pitavastatin or simvastatin in patients also receiving concomitant cyclosporine. (See Interactions.)

Warnings/Precautions

Interactions

Concomitant use with certain drugs may result in clinically important drug interactions, which could lead to adverse effects or reduced therapeutic effect of letermovir or concomitant drugs. (See Interactions.)

Consider potential for drug interactions prior to and during therapy. Review concomitant drugs and monitor for adverse effects associated with letermovir and concomitant drugs.

Specific Populations

Pregnancy

No adequate human data to assess if letermovir adversely affects pregnancy outcomes.

In animal studies, embryofetal developmental toxicity (including fetal malformations) observed in rats during organogenesis. No embryofetal developmental toxicity observed in rabbits at exposures that were not maternally toxic. In a rat pre- and post-natal development study, total litter loss observed at maternal letermovir exposures approximately twofold higher than human exposures at recommended human dosage.

Lactation

Distributed into milk in lactating rats and present in blood of nursing pups.

Not known if distributed into human milk, affects milk production, or affects breast-fed child.

Consider developmental and health benefits of breast-feeding along with the mother's clinical need for the drug and potential adverse effects on the breast-fed child from letermovir or the underlying maternal condition.

Pediatric Use

Safety and efficacy not established in pediatric patients <18 years of age. Pharmacokinetics not evaluated in pediatric patients.

Geriatric Use

Safety and efficacy similar between older and younger adults.

Data indicate age (18–78 years of age) does not have a clinically important effect on pharmacokinetics. Dosage adjustments based on age not needed.

Hepatic Impairment

Not recommended in patients with severe hepatic impairment (Child-Pugh class C).

Dosage adjustments not needed in patients with mild or moderate hepatic impairment (Child-Pugh class A or B).

Renal Impairment

Safety in patients with end-stage renal disease (Clcr ≤10 mL/minute), including those receiving dialysis, not known. Dosage adjustments not needed in patients with Clcr >10 mL/minute.

If IV letermovir used in patients with Clcr <50 mL/minute, closely monitor Scr concentrations; accumulation of IV vehicle (i.e., hydroxypropyl betadex) could occur.

Common Adverse Effects

Nausea, diarrhea, vomiting, peripheral edema, cough, headache, fatigue, abdominal pain.

Interactions for Letermovir

Substrate of CYP3A and 2D6. Moderate inhibitor of CYP3A; also induces CYP3A. Reversible inhibitor of CYP2C8. Expected to induce CYP2C9 and 2C19. Not metabolized by CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2E1, or 4A11; does not inhibit CYP1A2, 2A6, 2C9, 2C19, 2D6, or 2E1; and does not induce CYP1A2.

Substrate of organic anion transporter polypeptide (OATP) 1B1 and 1B3. Inhibits OATP1B1, 1B3, and renal organic anion transporter (OAT) 3; does not inhibit OAT2B1 or OAT1. Transport not mediated by OATP2B1 or OAT1.

Metabolized by UGT1A1 and 1A3 to a minor extent. Not metabolized by UGT1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7, 2B15, or 2B17; does not inhibit UGT1A4, 1A6, 1A9, or 2B7.

Substrate and inhibitor of P-glycoprotein (P-gp) transport.

Inhibits breast cancer resistance protein (BCRP), bile salt export pump (BSEP), and multidrug resistance-associated protein (MRP) 2. Does not inhibit renal organic cation transporter (OCT) 1 or 2 and is not transported by OCT1, BCRP, or MRP2.

Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes

CYP3A substrates: Clinically important increased concentrations of such substrates may occur. Magnitude of CYP3A-mediated drug interactions may be different when letermovir used concomitantly with cyclosporine.

CYP2C8 substrates: Possible increased concentrations of such substrates.

CYP2C9 or 2C19 substrates: Possible decreased concentrations of such substrates.

Drugs Affecting or Affected by Organic Anion Transporters

OATP1B1 or 1B3 inhibitors: Possible increased letermovir concentrations.

OATP1B1 or 1B3 substrates: Clinically important increased concentrations of such substrates may occur. Magnitude of OATP1B1- or 1B3-mediated drug interactions may be different when letermovir used concomitantly with cyclosporine.

Drugs Affecting or Metabolized by UGT

UGT inhibitors: Clinically important changes in letermovir concentrations not expected.

Drugs Affected by P-glycoprotein Transport

P-gp inhibitors: Clinically important changes in letermovir concentrations not expected.

Drugs Affecting or Affected by Other Membrane Transporters

BCRP, BSEP, and MRP2 substrates: Concomitant use not evaluated; clinical effect of letermovir on such substrates not known.

Specific Drugs

Drug

Interaction

Comments

Antiarrhythmic agents (amiodarone, quinidine)

Amiodarone: Increased amiodarone concentrations expected

Quinidine: Increased quinidine concentrations expected; magnitude of interaction may be different if cyclosporine also used concomitantly

Amiodarone: If used concomitantly, closely monitor for amiodarone-associated adverse effects; frequently monitor amiodarone concentrations

Quinidine: If patient receiving letermovir and cyclosporine, also consider interactions between cyclosporine and quinidine

Anticonvulsants (phenytoin)

Phenytoin: Decreased phenytoin concentrations expected

Phenytoin: Frequently monitor phenytoin concentrations

Antidiabetic agents (glyburide, repaglinide, rosiglitazone)

Glyburide, repaglinide, rosiglitazone: Increased concentrations of antidiabetic agent expected

Glyburide, rosiglitazone: Frequently monitor glucose concentrations

Repaglinide: Frequently monitor glucose concentrations; if patient receiving letermovir and cyclosporine, concomitant use with repaglinide not recommended

Antifungal agents (fluconazole, posaconazole, voriconazole)

Fluconazole: No clinically important pharmacokinetic interactions

Posaconazole: No clinically important pharmacokinetic interactions

Voriconazole: Decreased voriconazole concentrations and AUC

Voriconazole: If concomitant use required, closely monitor for reduced voriconazole efficacy

Antimycobacterial agents (rifampin)

Rifampin: Decreased letermovir concentrations expected

Rifampin: Concomitant use with letermovir not recommended

Antiviral agents (acyclovir, cidofovir, foscarnet, ganciclovir)

Acyclovir, cidofovir, foscarnet, ganciclovir: No in vitro evidence of antagonistic anti-CMV effects with letermovir

Acyclovir: No clinically important pharmacokinetic interactions

Digoxin

No clinically important pharmacokinetic interactions

Ergot alkaloids (ergotamine, dihydroergotamine)

Ergotamine, dihydroergotamine: Increased concentrations of the ergot alkaloid expected due to inhibition of CYP3A by letermovir; may lead to ergotism

Ergotamine, dihydroergotamine: Concomitant use with letermovir contraindicated

Estrogens and progestins (ethinyl estradiol or levonorgestrel)

Ethinyl estradiol or levonorgestrel: No clinically important pharmacokinetic interactions

HMG-CoA reductase inhibitors (statins)

Atorvastatin: Increased atorvastatin AUC and peak plasma concentrations

Fluvastatin, lovastatin, pitavastatin, pravastatin, rosuvastatin, simvastatin: Increased concentrations of the statin expected

Atorvastatin: Do not exceed atorvastatin dosage of 20 mg daily and closely monitor for myopathy and rhabdomyolysis; in patient receiving letermovir and cyclosporine, concomitant use with atorvastatin not recommended

Fluvastatin, pravastatin, rosuvastatin: Dosage reduction of the statin may be required; closely monitor for myopathy and rhabdomyolysis

Lovastatin: Dosage reduction of lovastatin may be required; closely monitor for myopathy and rhabdomyolysis; in patients receiving letermovir and cyclosporine, concomitant use with lovastatin not recommended

Pitavastatin, simvastatin: Concomitant use not recommended; in patients receiving letermovir and cyclosporine, concomitant use with pitavastatin or simvastatin contraindicated

Immunosuppressive agents (cyclosporine, mycophenolate mofetil, sirolimus, tacrolimus)

Cyclosporine: Increased letermovir AUC and peak plasma concentrations; increased cyclosporine AUC, but no substantial effect on cyclosporine peak plasma concentrations

Mycophenolate mofetil: No clinically important pharmacokinetic interactions

Sirolimus: Increased sirolimus AUC and peak plasma concentrations

Tacrolimus: No substantial effect on letermovir exposures; increased tacrolimus AUC and peak plasma concentrations

Cyclosporine: Decrease letermovir dosage to 240 mg once daily; during concomitant use and after letermovir discontinued, frequently monitor cyclosporine whole blood concentrations and adjust cyclosporine dosage accordingly

Sirolimus, tacrolimus: During concomitant use and after letermovir discontinued, frequently monitor immunosuppressive agent whole blood concentrations and adjust dosage accordingly

Midazolam

Increased midazolam AUC; magnitude of interaction may be different if patient receiving letermovir and cyclosporine

If patient receiving letermovir and cyclosporine, also consider interactions between cyclosporine and midazolam

Opiate agonists (alfentanil, fentanyl)

Alfentanil, fentanyl: Increased concentrations of the opiate agonist expected; magnitude of interaction may be different if cyclosporine also used concomitantly

Alfentanil, fentanyl: If patient receiving letermovir and cyclosporine, also consider interactions between cyclosporine and the opiate agonist

Pimozide

Increased pimozide concentrations expected due to inhibition of CYP3A by letermovir; may lead to QT interval prolongation and torsades de pointes

Concomitant use with letermovir contraindicated

Proton-pump inhibitors (omeprazole, pantoprazole)

Omeprazole, pantoprazole: Decreased proton-pump inhibitor exposures expected

Omeprazole, pantoprazole: Clinically monitor and adjust dosage of proton-pump inhibitor if needed

Warfarin

Decreased warfarin concentrations expected

Frequently monitor INR

Letermovir Pharmacokinetics

Absorption

Bioavailability

240–480 mg orally (without cyclosporine) in healthy individuals: 94%.

480 mg orally (without cyclosporine) in HSCT recipients: 35%.

240 mg orally (with cyclosporine) in HSCT recipients: 85%.

Food

When administered orally with food, peak plasma concentrations 30% higher and AUC similar to that observed when administered in fasting state.

Plasma Concentrations

Oral: Peak plasma concentrations occur 0.75–2.25 hours after a dose.

IV: Peak plasma concentrations occur at end of infusion.

Steady-state concentrations achieved within 9–10 days.

Distribution

Plasma Protein Binding

99%.

Elimination

Metabolism

Metabolized to minor extent by UGT1A1 and 1A3.

Elimination Route

Eliminated via hepatic uptake by OATP1B1 and 1B3.

Following single oral dose, 93% excreted in feces (70% as unchanged drug) and <2% excreted in urine.

Half-life

Following IV administration, mean terminal half-life is 12 hours.

Special Populations

Hepatic impairment: AUC approximately 1.6- or 3.8-fold higher in individuals with moderate or severe hepatic impairment (Child-Pugh class B or C), respectively, compared with healthy individuals.

Renal impairment: AUC approximately 1.9- or 1.4-fold higher in individuals with moderate or severe renal impairment, respectively, compared with healthy individuals. Not known if dialysis removes letermovir from systemic circulation.

Stability

Storage

Oral

Tablets

20–25°C (may be exposed to 15–30°C). Store in original package until use.

Parenteral

Concentrate for Injection, for IV Infusion

20–25°C (may be exposed to 15–30°C). Store in original carton; protect from light.

Following dilution with 0.9% sodium chloride or 5% dextrose, stable at room temperature for up to 24 hours or under refrigeration (2–8°C) for up to 48 hours; this includes storage in the IV bag and duration of IV infusion.

Compatibility

For information on systemic interactions resulting from concomitant use, see Interactions.

Parenteral

Solution Compatibility1 HID

Compatible

Dextrose 5%

Sodium chloride 0.9%

Drug Compatibility1 HID
Y-Site Compatibility

Compatible

Amphotericin B lipid complex

Ampicillin sodium

Ampicillin sodium-sulbactam sodium

Anidulafungin

Antithymocyte globulin

Caspofungin

Cefazolin sodium

Ceftaroline

Ceftriaxone sodium

Daptomycin

Doripenem

Famotidine

Fentanyl citrate

Fluconazole

Folic acid

Furosemide

Ganciclovir sodium

Hydrocortisone sodium succinate

Insulin, regular

Magnesium sulfate

Methotrexate

Micafungin

Morphine sulfate

Norepinephrine bitartrate

Pantoprazole sodium

Potassium chloride

Potassium phosphate

Tacrolimus

Telavancin

Tigecycline

Incompatible

Amiodarone HCl

Amphotericin B liposomal

Aztreonam

Cefepime HCl

Ciprofloxacin

Cyclosporine

Diltiazem HCl

Filgrastim

Gentamicin sulfate

Levofloxacin

Linezolid

Lorazepam

Midazolam HCl

Mycophenolate mofetil HCl

Ondansetron

Palonosetron

Actions and Spectrum

  • Quinazoline antiviral; CMV DNA terminase complex inhibitor.

  • CMV DNA terminase complex is a heterodimeric enzyme with several protein subunits (pUL51, pUL56, pUL89) and is required for viral DNA processing and packaging. By inhibiting the terminase complex, letermovir interferes with production of proper-length genomes and virion maturation.

  • Letermovir has a very limited spectrum of antiviral activity. Active in vitro and in vivo against human CMV (HCMV), a human herpesvirus. More potent than ganciclovir against susceptible CMV in vitro and has been active in vitro against some ganciclovir-resistant strains. No inhibitory activity in vitro against other herpesviruses or other important human pathogenic viruses tested, including adenovirus type 2, Epstein-Barr virus (EBV), HBV, HCV, herpes simplex virus types 1 and 2 (HSV-1, HSV-2), human herpesvirus type 6 (HHV-6), HIV type 1 (HIV-1), influenza virus type A, and varicella-zoster virus (VZV).

  • CMV mutants with reduced susceptibility to letermovir selected in vitro in cell culture. Most letermovir resistance-associated substitutions reported to date involve pUL56 and positions 231 through 369.

  • Cross-resistance between letermovir and antivirals in other classes (e.g., DNA polymerase inhibitors) unlikely. Letermovir has been active against CMV with substitutions conferring resistance to DNA polymerase inhibitors (e.g., cidofovir, foscarnet, ganciclovir) and these DNA polymerase inhibitors have been active against CMV isolates with substitutions conferring resistance to letermovir.

Advice to Patients

  • Importance of reading the patient information provided by the manufacturer.

  • Importance of not missing or skipping doses and importance of continuing letermovir for the duration recommended by the clinician.

  • If a dose of letermovir is missed, advise patient to take the dose as soon as it is remembered. If a dose is missed and not remembered until it is time for the next dose, the missed dose should be skipped and the regular dosing schedule should be resumed. Do not double up on the dose or take more than the prescribed dose.

  • If using letermovir tablets, advise patients that the tablets may be taken without regard to food and should be swallowed whole.

  • Advise patient that letermovir may interact with other drugs.

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

  • Importance of advising patients of other important precautionary information. (See Cautions.)

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

Tablets, film-coated

240 mg

Prevymis

Merck

480 mg

Prevymis

Merck

Parenteral

Concentrate, for injection, for IV infusion only

20 mg/mL (240 and 480 mg)

Prevymis

Merck

AHFS DI Essentials™. © Copyright 2021, Selected Revisions June 3, 2019. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

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