Letermovir clinical trials
Letermovir is named as an intervention in 9 current clinical trials in our China, France, USA, Spain, Canada and South Korea registers. 7 are recruiting patients now. The most common phase is Phase 3. The sponsor with the most trials is Assistance Publique - Hôpitaux de Paris (2). The most-studied condition is Cytomegalovirus Prophylaxis.
Where Letermovir is approved
All regulators →Of the three regulators tracked here, the first to approve Letermovir was Canada, on 1 Nov 2017. It is approved in 3 of the 3 regulators tracked here.
- 1 EU orphan designation, most recently for treatment of cytomegalovirus disease in patients with impaired cell-mediated immunity (6 Jun 2012, withdrawn)
- 1 EU safety letter (DHPC), latest: for Prevymis, 11 Sep 2020
From the regulators' own registers: FDA Drugs@FDA, the EMA medicines list and Health Canada's Notice of Compliance database. Dates are the first listed approval of a product containing only this substance; combination products and nationally authorised EU medicines are not counted.
Letermovir patents and exclusivity
Expiry tracker →Protections still running for marketed products containing Letermovir, as listed by the regulators. Expired patents and exclusivities, and discontinued products, are not shown.
- 2 listed patents; the last listed expires 28 Feb 2033 (US 10603384).
- Latest patent on the drug substance itself: 18 Jan 2029 (US RE46791).
- Exclusivity ODE-495: Orphan drug exclusivity: prophylaxis of cytomegalovirus (cmv) disease in pediatric patients 12 years of age and older and weighing at least…, until 30 Aug 2031.
- Exclusivity ODE-497: Orphan drug exclusivity: prophylaxis of cytomegalovirus (cmv) infection and disease in pediatric patients 6 months of age and older and wei…, until 30 Aug 2031.
- Exclusivity ODE-423: Orphan drug exclusivity: for prophylaxis of cytomegalovirus (cmv) disease in adult kidney transplant recipients at high risk (donor cmv ser…, until 5 Jun 2030.
- Exclusivity ODE*: FDA has not recognized orphan-drug exclusivity (ode) for this drug, but it contains the same active moiety or moieties as another drug(s) t…, until 5 Jun 2030.
- Exclusivity NPP: New patient population, until 30 Aug 2027.
- Exclusivity NP: New product, until 30 Aug 2027.
- PREVYMIS for prevention of cytomegalovirus disease in patients with impaired cell-mediated immunity deemed at risk: until 10 Jan 2030 (includes 24 months' paediatric extension). Union Register
Reproduced from the FDA Orange Book and Purple Book (checked 8 Nov 2026) and the European Commission's Union Register of medicinal products (CC BY 4.0; the EU expiry date is calculated exactly as the Commission's register displays it). Listed patents and dates are as submitted to or published by the regulator and may not reflect litigation, invalidation, settlements, lapsed fees or later extensions. This is not legal advice or a freedom-to-operate opinion, and it does not say when a generic or biosimilar will launch.
What health systems spend on Letermovir
All medicines →From NHSBSA Prescription Cost Analysis (Open Government Licence v3.0) and CMS State Drug Utilization Data. Both are gross amounts: neither system publishes its discounts or rebates per drug. Products combining several substances are not counted here.
How Letermovir works
All drug targets →- DNA terminase inhibitor InhibitorChEMBL only
- HIV infectious diseasePhase 2
Mechanisms and diseases from ChEMBL via the Open Targets Platform (release 26.09), ChEMBL record CHEMBL1241951, CC BY-SA 3.0. The Guide to Pharmacology has no record of this medicine, so its targets rest on ChEMBL alone. Trial phases are not approvals: approved uses are shown from the regulators' own records where we hold them.
NICE appraisals of Letermovir
All NICE appraisals →NICE, which decides whether the NHS in England should fund new medicines, has published 2 technology appraisals of Letermovir. 2 are current, and 1 of these recommend it for at least some patients.
| Appraisal | NICE recommendation | Published | Status |
|---|---|---|---|
| Letermovir for preventing cytomegalovirus infection after a kidney transplant (terminated appraisal) NICE TA1082 | Terminated (no company submission) | 23 Jul 2025 | Current |
| Letermovir for preventing cytomegalovirus disease after a stem cell transplant NICE TA591 | Recommended | 31 Jul 2019 | Current |
NICE decisions apply to the NHS in England. In Ireland the HSE decides on reimbursement, advised by the National Centre for Pharmacoeconomics. Titles, categories and dates link to the guidance on nice.org.uk. © NICE 2026 technology appraisal guidance. Available from www.nice.org.uk/guidance. All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication.
Patient leaflets for Letermovir
The package leaflet is the official guide for patients that comes with every medicine. These links go to the regulators that publish it.
- IEIreland: 6 products on the HPRA listEach product record links to the HPRA, which publishes the leaflet and SmPC.
- EUEuropean Union: PrevymisEMA product information: package leaflet and summary of product characteristics in every EU language.
- UKUnited Kingdom: Search MHRA ProductsPatient information leaflets and SmPCs for UK-licensed products.
- USUnited States: Search DailyMedFDA-approved labels, including patient and medication guides.
Leaflets differ between brands and countries; always read the one that comes with your own medicine. This is regulatory information, not medical advice.
Reference identifiers for Letermovir
- ATC code
- J05AX18
- ChEMBL
- CHEMBL1241951
- DrugBank
- DB12070
- PubChem CID
- 45138674
- CAS number
- 917389-32-3
- FDA UNII
- 1H09Y5WO1F
- Wikidata
- Q15409407
- Wikipedia
- Letermovir
Codes that identify this medicine in other databases, from Wikidata (CC0), matched by its ChEMBL ID. The ATC code is the WHO classification of what the medicine is used for.
Trials by status
Trials by phase
Clinical trials of Letermovir
9 trialsRegisters list studies that are recruiting, about to open, active but closed to enrolment, or enrolling by invitation. The UK and USA registers cover industry-sponsored studies only. Trial titles and statuses are copied from the registry as published.
Letermovir across our data
Ireland · EU · USThe same active substance in our other registers, matched by its exact name. Each entry links to the register record it comes from.
Licensed in Ireland (HPRA)
6 single-substance products containing Letermovir on the HPRA medicines list.
- PREVYMIS 120 mg granules in sachetMerck Sharp & Dohme BV, · EU/1/17/1245/006
- PREVYMIS 20 mg granules in sachetMerck Sharp & Dohme BV, · EU/1/17/1245/005
- PREVYMIS 240 mg Concentrate for solution for infusionMerck Sharp & Dohme BV · EU/1/17/1245/003
- PREVYMIS 240 mg Film-coated tabletMerck Sharp & Dohme BV, · EU/1/17/1245/001
- PREVYMIS 480 mg Concentrate for solution for infusionMerck Sharp & Dohme BV · EU/1/17/1245/004
Supply shortages
No entry for Letermovir in the EMA, FDA or German BfArM shortage lists we track.
Conditions studied with Letermovir
13 conditionsAll 13 conditions
| Condition (as registered) | Trials |
|---|---|
| Cytomegalovirus Prophylaxis | 1 |
| EBV-associated T/NK-cell Lymphoproliferative Diseases | 1 |
| Refractory/Relapsed EBV-related Hemophagocytic Lymphohistiocytosis | 1 |
| Letermovir | 1 |
| Hematologic Malignancy | 1 |
| Kidney Transplant | 1 |
| Cytomegalovirus Infection | 1 |
| Pregnant Women | 1 |
| CMV Infected Fetuses | 1 |
| Infections, Cytomegalovirus | 1 |
| CMV | 1 |
| Lung Transplant Recipient | 1 |
| Relapsed Refractory Multiple Myeloma (RRMM) | 1 |
Sponsors
lead sponsor per trialBy country register
| Register | Trials | Recruiting |
|---|---|---|
| Clinical trials in China | 3 | 2 |
| Clinical trials in France | 2 | 2 |
| Clinical trials in USA | 1 | 1 |
| Clinical trials in Spain | 1 | 0 |
| Clinical trials in Canada | 1 | 1 |
| Clinical trials in South Korea | 1 | 1 |
A trial with sites in more than one country appears in each of those registers.
Related compounds
Questions about Letermovir trials
How many clinical trials are testing Letermovir?
9 current trials in our China, France, USA, Spain, Canada and South Korea registers name Letermovir (also registered as MK-8228) as a drug or biological intervention, as of the registry sync on 9 November 2026. Completed and withdrawn studies are not counted.
Are Letermovir trials recruiting patients?
Yes. 7 of the 9 trials are recruiting: 2 with sites in China, 2 with sites in France, 1 with sites in USA, 1 with sites in Canada and 1 with sites in South Korea. Eligibility and site contacts are on each trial's record. Only the study team can confirm whether a patient is eligible.
Who sponsors Letermovir clinical trials?
Assistance Publique - Hôpitaux de Paris (2), Merck Sharp & Dohme LLC (1), Beijing Children's Hospital (1) and Ruijin Hospital (1), among 8 lead sponsors in total. The number in brackets is how many trials each organisation leads.
Is Letermovir licensed in Ireland?
Yes. The HPRA medicines list includes 6 single-substance products containing Letermovir, for example PREVYMIS 120 mg granules in sachet (Merck Sharp & Dohme BV,). A licence does not mean a product is currently marketed or reimbursed; see each product's record.
Is there a Letermovir shortage?
Not in the lists we track: Letermovir has no entry in the EMA, FDA or German BfArM shortage registers as of their latest sync.
Where does this information come from?
Every trial, status, phase and sponsor on this page is copied from public ClinicalTrials.gov records by a daily sync. Nothing here describes how Letermovir works or whether it is effective, and it is not medical advice.
How this page is built
Everything on this page is copied from public ClinicalTrials.gov registry records — it is not written from memory, and nothing here describes how Letermovir works or whether it is effective. Each trial links to its own record so you can check it yourself.
- ClinicalTrials.gov (U.S. National Library of Medicine) ↗ Trial IDs, titles, intervention names and synonyms, phase, overall status, lead sponsor and conditions for every trial on this page
This page is built automatically: a daily sync job reads the registry records behind our country trial registers, collects every trial that lists Letermovir (or a registered synonym) as a drug or biological intervention, and tabulates the registry fields directly. Placebos and generic comparators are excluded. There is no AI drafting and no per-compound editorial pass, and the page has not been clinically reviewed. The “last verified” date above is the timestamp of that sync, not a review date. Our general editorial approach is described in our editorial standards and corrections policy. The ClinicalTrials.gov data on this page was last retrieved on 9 Nov 2026. How every register is built: methodology · fixes we have made: corrections log.