TheraRadar
Data updated: May 26, 2026

PREVYMIS (letermovir)

DNA Terminase Complex Inhibitors Trial Activity: Expansion 17 active trials
First-in-Class Orphan Drug Breakthrough Therapy Priority Review Fast Track
Infectious Disease Approved 2017-11-08

Prevymis (letermovir) is an antiviral indicated for the prophylaxis of cytomegalovirus (CMV) infection and disease in CMV-seropositive recipients [R+] of an allogeneic hematopoietic stem cell transplant (HSCT) in adults and pediatric patients 6 months of age and older weighing at least 6 kg. It is also indicated for the prophylaxis of CMV disease in kidney transplant recipients at high risk (Donor CMV-seropositive/Recipient CMV-seronegative [D+/R-]) in adults and pediatric patients 12 years of age and older weighing at least 40 kg.

Source: FDA Label • Merck • Cytomegalovirus DNA Terminase Complex Inhibitor

How PREVYMIS Works

Letermovir is a CMV DNA terminase complex inhibitor. It functions by targeting the CMV DNA terminase complex (specifically subunits pUL51, pUL56, and pUL89), which is required for viral DNA processing and packaging. By inhibiting this complex, the drug prevents the cleavage of long-chain DNA concatemers into individual mature genomes, thereby blocking the production of infectious mature virions. Unlike many other CMV antivirals, its mechanism does not involve the inhibition of viral DNA polymerase.

Development Insights

Merck Sharp & Dohme LLC conducting 5 trials (20%)
47 indications explored (Broad Platform)
cytomegalovirus infections (4 trials)
cmv (3 trials)
chronic lymphocytic leukemia (3 trials)
4
Indications
--
Phase 3 Trials
3
Priority Reviews
8
Years on Market

Details

Status
Prescription
First Approved
2017-11-08
Patent Cliff
2033
Revenue
$215M (Q4-2024)

Pro Metrics

Patent cliff and revenue data

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Routes
INTRAVENOUS, ORAL
Dosage Forms
SOLUTION, TABLET, PELLETS

Companies

Active Ingredient: LETERMOVIR

PREVYMIS Approval History

2018
2019
2020
2021
2022
2023
2024
2025
2026
Original
New Indication
New Form
Label Update
46 FDA actions from 2017 to 2025 · 3 indication expansions
Jan 2025 SUPPL
Label · Labeling
Aug 2024 SUPPL Priority
Efficacy
Aug 2023 SUPPL
Efficacy

What PREVYMIS Treats

2 indications

PREVYMIS is approved for 2 conditions since its original approval in 2017. These indications span multiple therapeutic areas including oncology, immunology, and more.

  • Cytomegalovirus Infection
  • Cytomegalovirus Disease
Source: FDA Label

PREVYMIS Competitive Set

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Three rings of competition based on shared molecular targets and treated indications.

Indication competitors

3

Same indication, different mechanism — what else might this patient receive?

Unlock 1 more competitors across all three rings.
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Filters applied: drops same-active-ingredient (505(b)(2) reformulations), route-mismatch (topical vs systemic), and cross-therapeutic-area matches in same-indication rings.

Drugs Similar to PREVYMIS

FDA-approved drugs for similar conditions. Compare mechanisms and indications to understand treatment alternatives.

LIVTENCITY
MARIBAVIR
2 shared
Takeda
Shared indications:
Cytomegalovirus InfectionCytomegalovirus Disease
GANCICLOVIR SODIUM
GANCICLOVIR SODIUM
1 shared
PH HEALTH
Shared indications:
Cytomegalovirus Disease
VALCYTE
VALGANCICLOVIR HYDROCHLORIDE
1 shared
CHEPLAPHARM
Shared indications:
Cytomegalovirus Disease
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Clinical Trial Registry

26 trials
Trial Sponsor ID Phase Status Title
NCT07199465 8228-077 MK-8228-077 Ph 1 recruiting A Clinical Study of Letermovir (MK-8228) in Children and Adolescents Who Receive a Kidney Transplant (KT) (MK-8228-077)
NCT07571135 STUDY00000831 Ph 4 not yet recruiting Letermovir vs Valganciclovir in CMV R+ Kidney Transplant
NCT06118515 21-0027 5U54AI150225-05 Ph 1 recruiting A Safety Assessment of Oral Letermovir in Infants With Symptomatic Congenital Cytomegalovirus
NCT05711667 ACCL1932 NCI-2022-10769, ACCL1932 Ph 3 recruiting A Study of the Drug Letermovir as Prevention of Cytomegalovirus Infection After Stem Cell Transplant in Pediatric Patients
NCT05041426 results posted STUDY21040074 Ph 2 completed Letermovir for CMV Prevention After Lung Transplantation
NCT05446571 CYMEVAL3-step2 APHP180592_step2 2020-002924-35 Ph 3 recruiting Prenatal Treatment of Congenital Cytomegalovirus Infection With Letermovir Versus Valaciclovir
NCT07020533 24168 NCI-2025-03633, 24168 Ph 1 recruiting A Vaccine (CMV-MVA Triplex Vaccine) for the Enhancement of CMV-Specific Immunity and the Prevention of CMV Viremia in Patients Undergoing Haploidentical Hematopoietic Stem Cell Transplant
NCT07235683 CLEAR-CMV 25-5760 Ph 4 recruiting Combination Letermovir and Standard of Care Antiviral for Enhanced Antiviral Response in Cytomegalovirus Infection in Lung Transplant Recipients
NCT06575374 2023-0828 NCI-2024-07402 Ph 2 recruiting Single Arm Pilot Trial of Letermovir for CMV Prophy in CAR T Cell
NCT06334497 LUCY-1 APHP220791 2023-506216-40-00 Ph 3 recruiting Letermovir-based Dual Therapy for Treatment of Cytomegalovirus Infections
NCT06449586 RJBMT-2024-02 Ph 3 active not recruiting CMV-specific T Cell Immunity Test Indicated Prophylaxis of Letermovir After All-HSCT
NCT07266467 CAPS01 XJTUAF2025-CAPS01 Ph 4 recruiting Efficacy and Safety of Leymovir Versus Valganciclovir in Prevention of Cytomegalovirus Infection and Cytomegalovirus Disease in Chinese Kidney Transplant Recipients
NCT06920251 OPTIMUS-EL H-2503-044-1261 Ph 2 recruiting Phase II Trials of Letermovir Prophylaxis in Patients With RRMM Undergoing Elranatamab Therapy
NCT04060277 results posted 19065 NCI-2019-04888, 19065 Ph 2 active not recruiting Triplex Vaccine in Preventing CMV Infection in Patients Undergoing Hematopoietic Stem Cell Transplantation
NCT06407232 2024-0174 A561000, Protocol Version 8/22/25 Ph 3 recruiting Letermovir (Prevymis) for CMV in Kidney and Pancreas Transplant Recipients
NCT07079735 VALET-CMV AAAV8422 Ph 2, Ph 3 recruiting Valganciclovir vs. Letermovir for CMV Prophylaxis in Heart Transplant
NCT04904614 results posted 00001538 Ph 4 completed Letermovir Use in Heart Transplant Recipients
NCT06453460 4005 UCI 22-188 Ph 2 recruiting CMV-TCIP Directed Letermovir Prophylaxis After Allo-SCT
NCT05626530 00003219 Ph 4 recruiting Letermovir for Secondary Prophylaxis in Solid Organ Transplant Recipients
NCT05763823 results posted 8228-045 MK-8228-045 Ph 3 completed A Study of Letermovir (MK-8228) to Evaluate Efficacy and Safety for Prevention of Cytomegalovirus Infection in Chinese Hematopoietic Stem Cell Transplant Recipients (MK-8228-045)
NCT04312841 results posted OSU-19289 NCI-2020-00169 Ph 2 completed Letermovir for the Prevention of Cytomegalovirus Reactivation in Patients With Hematological Malignancies Treated With Alemtuzumab
NCT06626555 PROACTIV 125096 2020-000288-22 Ph 2 not yet recruiting Clinical Trial to Evaluate the Effects of Letermovir Prophylaxis on T-cell Immune Activation in Participants With Treated HIV-1 Infection
NCT03930615 results posted 8228-040 MK-8228-040, 194797 Ph 3 completed Extension of Letermovir (LET) From Day 100 to Day 200 Post-transplant for the Prevention of Cytomegalovirus (CMV) Infection in Hematopoietic Stem Cell Transplant (HSCT) Participants (MK-8228-040)
NCT03443869 results posted 8228-002 MK-8228-002, 2017-001055-30 Ph 3 completed Letermovir Versus Valganciclovir to Prevent Human Cytomegalovirus Disease in Kidney Transplant Recipients (MK-8228-002)
NCT03728426 results posted 18-348 Ph 2 completed Letermovir Treatment for Refractory or Resistant Cytomegalovirus Infection
NCT02137772 results posted 8228-001 2013-003831-31, 152923 Ph 3 completed Letermovir (MK-8228) Versus Placebo in the Prevention of Clinically-Significant Cytomegalovirus (CMV) Infection in Adult, CMV-Seropositive Allogeneic Hematopoietic Stem Cell Transplant Recipients (MK-8228-001)
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Active Pipeline

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Ongoing clinical trials by development phase

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Key Completed Trials

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Completed studies with published results, ranked by significance

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Trial Timeline

Full development history with FDA approval milestones

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Understanding FDA Approval Types
Count Type What it means
- ORIG Original approval - drug first enters market
- SUPPL - Efficacy New indication (new disease/condition approved)
- SUPPL - Labeling Label text changes (warnings, dosing updates)
- SUPPL - Manufacturing Production changes (new facility)
- SUPPL - Chemistry Formulation changes (new dosage strength)

Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.

PREVYMIS FDA Label Details

Indications & Usage

FDA Label (PDF)

PREVYMIS is indicated for the treatment of Cytomegalovirus Infection; Cytomegalovirus Disease.

View full patent landscape →
2 OB patents · 2 families · 130 international docs across 50 countries

PREVYMIS Patents & Exclusivity

Latest Patent: Feb 2033
Exclusivity: Aug 2031

Patents (2 active)

US10603384 Expires Feb 28, 2033
USRE46791 Expires Jan 18, 2029

Exclusivity

D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
D-189 Until Aug 2026
I-916 Until Jun 2026
NPP Until Aug 2027
ODE-423 Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
NP Until Aug 2027
ODE* Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
NP Until Aug 2027
ODE* Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
NP Until Aug 2027
ODE* Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
NP Until Aug 2027
ODE* Until Jun 2030
ODE-495 Until Aug 2031
ODE-497 Until Aug 2031
Source: FDA Orange Book

Pro Intelligence Preview

Deep insights for PREVYMIS

Revenue Insights

  • Q4-2024: $215M
  • Historical trend analysis

Patent Timeline

  • Cliff: 2033
  • 16 active patents

Trial Analysis

  • 25 total trials
  • Stage: Expansion

Competitive Landscape

  • 3 similar drugs
  • Same target/indication analysis
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Full approval history • All patents • Revenue trends • Competitor analysis

Data Sources

Data sourced from official FDA and NIH databases. Click links to verify on original sources.

How We Calculate These Metrics

Trial Activity Stage

Measures the current development activity pattern based on trial phases, status, and trends. Important: This measures R&D activity, not commercial lifecycle.

Trial statuses: "Active" means recruiting or ongoing. "Completed" means reached planned endpoint. "Terminated" means stopped early—often due to safety, efficacy, or business reasons.

  • Growth: High proportion of early-phase trials (Phase 1/2), active development
  • Expansion: Significant Phase 3 activity, approaching or pursuing approvals
  • Mature: Substantial Phase 4 post-marketing studies
  • Stable: Mixed phase distribution, steady development
  • Declining: Low active trial ratio, reduced R&D investment