Letermovir

PREVYMIS

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Pronunciation: le-TERM-oe-veer (PRE-vi-mis)

Letermovir ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Letermovir ballicule

What it isCMV terminase complex inhibitor; CMV prophylaxis after stem cell transplant.

Why this oneIt has no myelosuppression, unlike ganciclovir, which matters in a marrow already recovering.

What limits itProphylaxis only; it does not treat established CMV disease. It inhibits CYP3A4 and raises cyclosporine and tacrolimus.

Letermovir molecular structure (skeletal formula) — Molecular structure: Letermovir

FDA-approved for

CMV prophylaxis after transplant (2017)

FDA label

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FDA dosing	Population	Start	Target	Max
CMV prophylaxis (HSCT)	Adults & peds ≥12 yr, ≥30 kg	480 mg QD	480 mg QD	480 mg QD
CMV prophylaxis (kidney transplant)	Adults & peds ≥12 yr, ≥40 kg	480 mg QD	480 mg QD	480 mg QD
CMV prophylaxis (HSCT)	Peds 6 mo–<12 yr (weight-based)	weight-based QD	40–480 mg QD by weight (6 kg–≥30 kg)	480 mg QD

Renal No adjustment for CLcr >10 mL/min; insufficient data if CLcr ≤10 mL/min or on dialysis. With IV formulation and CLcr <50 mL/min, monitor serum creatinine (hydroxypropyl betadex accumulation).

Hepatic No adjustment for mild–moderate (Child-Pugh A/B); not recommended in severe (Child-Pugh C).

With cyclosporine, reduce to 240 mg QD in patients ≥12 yr.

Instructions

Tablets: swallow whole, with or without food.
Oral pellets: mix with soft food (≤ room temp) or give via NG/G tube; do not crush or chew.
Injection: dilute before use; infuse over 1 hr through 0.2/0.22 micron PES in-line filter; use only if unable to take oral, do not exceed 4 weeks; not as IV bolus; avoid DEHP-containing IV bags/sets.
HSCT: start Day 0–28, continue to Day 100 (or 200 if late-CMV risk). Kidney: start Day 0–7, continue to Day 200.

Available strengths

tab 240, 480 mg
pellets 20, 120 mg/packet
pellet 20, 120 mg
inj 20 mg/mL

Contraindications

Pimozide (CYP3A inhibition → ↑pimozide, QT prolongation/torsades)
Ergot alkaloids (ergotamine, dihydroergotamine) — risk of ergotism
Pitavastatin or simvastatin when co-administered with cyclosporine (myopathy/rhabdomyolysis)

Cautions

Significant CYP3A drug interactions — review concomitant meds
IV formulation contains hydroxypropyl betadex: accumulation in renal impairment, potential ototoxicity (animal); limit IV to ≤4 weeks

Adverse reactions

Nausea, diarrhea, vomiting
Peripheral edema, cough, headache, fatigue, abdominal pain
Cardiac events (tachycardia, atrial fibrillation)

Pregnancy No adequate human data; animal embryo-fetal toxicity/malformations at ~11x human exposure.

Lactation Unknown in human milk; present in milk of lactating rats.

Cost

Letermovir (PREVYMIS)

Strength		#/mo	CostPlus
240 mg	tab	30 qd	not offered
480 mg	tab	30 qd	not offered
20 mg/mL	inj	per unit	not offered
20 mg/packet	pellets	per unit	not offered
120 mg/packet	pellets	per unit	not offered
20 mg	pellet	per unit	not offered
120 mg	pellet	per unit	not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Letermovir is administered under clinical supervision and dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

Generic entry2033 est.

NO BOXED WARNINGS

Principal riskProphylaxis only; it raises tacrolimus and cyclosporine

Classes and tags

Clinical profile

Therapeutic safety burden2 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk2 / 4

Legacy pregnancy categoryNot assigned — PLLR-era drug

Defining liabilityAgent-specific renal, hepatic, hematologic, metabolic and drug-interaction toxicity.

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