Prevymis Generic: When Will Generic Letermovir Be Available?
This page is aggregated from FDA records, court filings and company announcements. Coded and designed by Dr. Brian Staiger, PharmD, BCPS
Updated October 9, 2026 How we build our data
Prevymis Generic at a Glance
Four quick answers from FDA records and our estimate.
- When is the first generic expected? February 2033 About 6.5 years away Why then?
- Has the FDA approved a generic? Not yet 1 company holds a tentative approval Why not yet?
- When does the last patent end? February 2033 2 patents listed with the FDA
- Can you buy a generic today? Not yet No company lists one for sale
Generic letermovir is expected to be available in February 2033, about 6.5 years away, first for Prevymis injection. None is for sale yet. Each product has its own month below.
Why February 2033?
It is when Prevymis’s patent 10,603,384 ends. That patent covers the product’s formulation, and once it ends, generics can go on sale as soon as the FDA approves them. We rate it probable: more likely than not, but it can still move.
Why hasn’t the FDA approved a generic yet?
That is normal before a launch. The FDA usually can’t give a generic its final approval while a patent or exclusivity still blocks it, so final approval often comes close to the day the generic can be sold. One company already holds a “tentative” approval, the FDA’s word for a generic that is ready but still blocked: Zydus Pharms USA Inc (March 2024). See who is lined up
Will the generic cost less?
Usually, and more so as more companies sell one. One company has applied to the FDA to make it. In the FDA’s study of past launches, pharmacies paid about 31% less once one company sold a generic. See the price pattern
What should I do now?
Keep taking Prevymis as prescribed. When a generic arrives, your pharmacy may switch you to it automatically, and it may look different. What a generic means for you
- tabletsOctober to December 2028Likely · settlement between companies
- injectionFebruary 2033Probable · patent expires
Our month is only an estimate based on available information, so we never name a day.
Prevymis by the Numbers
- Reason
- Patent expiresA patent that protects the brand runs out. After that, approved generics can be sold.
- How sure
- Probable More likely than not, but it can still move.
- Price competition
- Low 1 company has filed, 1 first in line
- Brand sales
- $608M a yearBig seller, all 2 products
- FDA approved 2017 November 2017 FDA Orange Book
- Patents listed 2 last runs to February 2033 FDA Orange Book
- Medicare Part D spent $197.6M in 2025, for 5,842 people CMS Part D Spending by Drug
- Medicaid prescriptions 4,765 in the last four reported quarters, $36.7M CMS Medicaid drug utilization, to Q1 2026
Prevymis’s Road to a Generic
Prevymis has had the market to itself since the FDA approved it in November 2017 (Merck Sharp And Dohme LLC). Its FDA protection (orphan drug) runs to August 2031. Its 2 listed patents run to February 2033. Generic companies have challenged its patents with the FDA since October 2024.
The first generic of Prevymis is expected in February 2033.
Why that month: patent 10,603,384, on the product’s formulation, ends then.
Each bar runs from the brand’s approval to the day that protection ends. The green band is our projection for the first generic: a month, never a day, because legal dates move and a generic reaches shelves days to weeks after it is allowed. Sources: FDA Orange Book; the expected month from court records and company announcements.
Prevymis Patents and FDA Protections
Every patent and exclusivity the FDA Orange Book lists for Prevymis’s own applications. A protection running past the expected month does not mean the date is wrong: a settlement or a court ruling can let a generic in before a patent ends, and a patent on one formulation or use does not block every generic.
The one that matters for a generic launch: patent 10,603,384, which ends in February 2033, the month the first generic is expected.
| Patent | What it covers | Protects until | Status |
|---|---|---|---|
| RE46791 | The active ingredient; the product’s formulation | January 2029 | Active |
| 10,603,384 Sets the expected month of generic availability | The product’s formulation | February 2033 | Active |
| Exclusivity | What it means | Ends | Status |
|---|---|---|---|
| New use I-916 | Three years of protection for a newly approved use (indication). | June 2026 | Ended |
| New dosing D-189 | Three years of protection for a new way of dosing it. | August 2026 | Ended |
| New product NP | Three years of protection for a change that needed new clinical studies. | August 2027 | Active |
| New patient population NPP | Three years of protection for a newly approved group of patients. | August 2027 | Active |
| FDA exclusivity ODE* | A period of protection the FDA granted (code ODE*). | June 2030 | Active |
| Orphan drug ODE-423 | Seven years of protection for a use in a rare disease. | June 2030 | Active |
| Orphan drug ODE-495 | Seven years of protection for a use in a rare disease. | August 2031 | Active |
| Orphan drug ODE-497 | Seven years of protection for a use in a rare disease. | August 2031 | Active |
Source: FDA Orange Book, application 219104, 209940, 209939. Patent numbers open the patent on Google Patents.
Patent Challenges to Prevymis
The first patent challenge to Prevymis reached the FDA in October 2024, from one company on that first day. The FDA’s list has 2 entries for Prevymis, by form and strength. The FDA has not approved a first challenger’s generic yet.
What Is a Patent Challenge?
A generic company that wants to sell its version before Prevymis’s patents run out can tell the FDA that a patent is invalid, or that its version does not infringe it. The FDA calls this a “Paragraph IV certification.” The brand company usually sues, and the FDA then generally cannot approve that generic for up to 30 months while the case runs. To reward going first, the companies that challenge first can get a 180-day head start: the FDA cannot approve the generics that came after them until it ends.
| Product | First challenged | Companies that day | 180-day head start | First challenger’s generic | Challenged patents run to | |
|---|---|---|---|---|---|---|
| Approved | On sale | |||||
| Tablets, 240 mg and 480 mg | October 2024 | 1 company | No decision yet | Not yet | Not yet | January 2029 |
| Intravenous solution, 240 mg/12 mL and 480 mg/24 mL | March 2026 | 1 company | No decision yet | Not yet | Not yet | February 2033 |
Source: the FDA’s Paragraph IV Patent Certifications list, as of September 2026. The FDA began posting the 180-day decisions and the first challenger’s approval and first sale in June 2019: an older entry it has not updated since reads “Not posted”, and “Not yet” means the list records no such event. “Companies that day” is the FDA’s count of challenges that arrived on the first day.
Who Is Lined Up to Make Generic Letermovir
Three steps stand between a brand and a generic you can buy: a company applies to the FDA, the FDA approves it, and the company starts selling it.
Applied to the FDA
One company has applied to the FDA to make generic letermovir.
The FDA has tentatively approved one company’s generic: Zydus Pharms USA Inc (March 2024). A tentative approval means the generic is ready, but a patent or exclusivity still stops the FDA from giving it final approval.
First in line. One of them was first in line: the first company to challenge the brand’s patents can earn 180 days on the market before the other generics, which is why being first matters.
Generic companies have challenged Prevymis’s patents with the FDA since October 2024: see the patent challenges.
Approved by the FDA
Not yet. The FDA has not approved a generic letermovir. Final approval often comes close to the day a generic can be sold.
For Sale in Pharmacies
Not yet. No company lists a generic letermovir for sale with the FDA.
Sources: how many companies have applied, from court records and company announcements; approved generics from the FDA Orange Book; tentative approvals from Drugs@FDA; what is for sale from the FDA NDC Directory. The FDA does not disclose an application before it approves it (21 CFR 314.430).
Prevymis Price: What Pharmacies Pay and What Generics Usually Do
What a Generic Could Cost
How we estimate it. The national survey of what pharmacies pay (NADAC) has no recent price for Prevymis, so we cannot show dollars. Here is the FDA’s finding of how far the price pharmacies pay usually falls as generic companies join: about 31% with one company, 44% with two, 73% with four and over 95% with six or more (the typical drop for every drug whose first generic came out from 2015 to 2017).
Median prices pharmacies paid for the generic (invoice prices), compared with the brand’s price before generic entry, from FDA’s 2019 analysis “Generic Competition and Drug Prices”. At the manufacturer’s price FDA found steeper drops (about 39%, 54%, 79% and over 95%), the figures quoted elsewhere on this tracker. A typical pattern, not a price quote for this medicine.
What Medicare and Medicaid Spend on Prevymis
Big public spending is part of why generic makers line up for a medicine, and why its first generic matters beyond the pharmacy counter. Figures are before manufacturer rebates, which are confidential.
Medicare Part D Spending
What Medicare drug plans spent on Prevymis, before manufacturer rebates.
- $59.3M
- January to March 2026, the latest CMS has posted
For 3,426 people, about $7,718 per prescription fill - $197.6M
- 2025, the whole year
For 5,842 people, about $7,631 per prescription fill
See the numbers
| Period | Spending | People | Per fill |
|---|---|---|---|
| January to March 2026 | $59,338,966 | 3,426 | $7,718.39 |
| 2025 | $197,644,326 | 5,842 | $7,631.06 |
Source: CMS Medicare Part D Spending by Drug, matched by the brand name Prevymis only, so no generic is counted in it. What CMS says it is used for: This medication is used to prevent disease caused by a virus called cytomegalovirus (CMV) in people who have received a bone marrow transplant or kidney transplant. CMV disease can cause serious infections, including an infection in the eye, called CMV retinitis, that can cause blindness.
Medicaid Prescriptions by Quarter
4,765 prescriptions in the four quarters to Q1 2026, $36.7M paid.
See the numbers
| Quarter | Prescriptions | Medicaid paid |
|---|---|---|
| Q1 2026 | 1,279 | $9,934,908 |
| Q4 2025 | 1,270 | $9,581,978 |
| Q3 2025 | 1,144 | $8,750,874 |
| Q2 2025 | 1,072 | $8,405,057 |
| Q1 2025 | 1,045 | $8,068,371 |
Source: CMS Medicaid State Drug Utilization Data, over Prevymis’s own package codes.
Prevymis Strengths and Forms
| Strength | Form | How it is taken | Approved | Status |
|---|---|---|---|---|
| 240MG | Tablet | Oral | November 2017 | Prescription reference product |
| 240MG/12ML (20MG/ML) | Solution | Intravenous | November 2017 | Prescription reference product |
| 480MG | Tablet | Oral | November 2017 | Prescription reference product |
| 480MG/24ML (20MG/ML) | Solution | Intravenous | November 2017 | Prescription reference product |
| 120MG/PACKET | Pellets | Oral | August 2024 | Prescription reference product |
| 20MG/PACKET | Pellets | Oral | August 2024 | Prescription reference product |
Source: FDA Orange Book, Merck Sharp And Dohme LLC. Listed for sale today by Merck Sharp & Dohme LLC (FDA NDC Directory).
Prevymis NDC Codes and Packages
Each Prevymis package sold today has its own NDC, the product number printed on the box and on the pharmacy label. Open one to see that package’s details, what pharmacies pay for it and its patent timeline.
| NDC | Product | Package | Company |
|---|---|---|---|
| 00006-5085-01 | LETERMOVIR 120 mg/1 pellet | carton of 30 packets of 48 pellets | Merck Sharp & Dohme LLC |
| 00006-5086-01 | LETERMOVIR 20 mg/1 pellet | carton of 30 packets of 8 pellets | Merck Sharp & Dohme LLC |
| 00006-5003-01 | LETERMOVIR 20 mg/mL injection, solution | vial of 12 mL | Merck Sharp & Dohme LLC |
| 00006-5003-01 | LETERMOVIR 20 mg/mL injection, solution | vial of 12 mL | Merck Sharp & Dohme LLC |
| 00006-5004-01 | LETERMOVIR 20 mg/mL injection, solution | vial of 24 mL | Merck Sharp & Dohme LLC |
| 00006-5004-01 | LETERMOVIR 20 mg/mL injection, solution | vial of 24 mL | Merck Sharp & Dohme LLC |
| 00006-3075-02 | LETERMOVIR 240 mg/1 tablet, film coated | carton of 4 dose packs of 7 tablets | Merck Sharp & Dohme LLC |
| 00006-3075-02 | LETERMOVIR 240 mg/1 tablet, film coated | carton of 4 dose packs of 7 tablets | Merck Sharp & Dohme LLC |
Show the other 6 Prevymis packages
| NDC | Product | Package | Company |
|---|---|---|---|
| 00006-3075-04 | LETERMOVIR 240 mg/1 tablet, film coated | carton of 14 blister packs of 1 tablet | Merck Sharp & Dohme LLC |
| 00006-3075-04 | LETERMOVIR 240 mg/1 tablet, film coated | carton of 14 blister packs of 1 tablet | Merck Sharp & Dohme LLC |
| 00006-3076-02 | LETERMOVIR 480 mg/1 tablet, film coated | carton of 4 dose packs of 7 tablets | Merck Sharp & Dohme LLC |
| 00006-3076-02 | LETERMOVIR 480 mg/1 tablet, film coated | carton of 4 dose packs of 7 tablets | Merck Sharp & Dohme LLC |
| 00006-3076-04 | LETERMOVIR 480 mg/1 tablet, film coated | carton of 14 blister packs of 1 tablet | Merck Sharp & Dohme LLC |
| 00006-3076-04 | LETERMOVIR 480 mg/1 tablet, film coated | carton of 14 blister packs of 1 tablet | Merck Sharp & Dohme LLC |
Source: the FDA NDC Directory, current listings only. Only packages sold under Prevymis’s own FDA approval (NDA 219104, NDA 209940, NDA 209939) are listed, never a generic. Some codes belong to companies that repackage Prevymis: it is the same medicine in a different package.
What a Generic Prevymis Means for You
Nothing Changes Until It Is in Pharmacies
Until a generic is actually for sale, keep filling Prevymis as usual. When one arrives, there is nothing you need to sign up for.
Your Pharmacy May Switch You Automatically
Every state lets pharmacists fill a brand-name prescription with an FDA-approved generic rated as equivalent to it, and about 19 states require them to, unless your prescriber writes “dispense as written” or “brand medically necessary” on the prescription. Some states ask the pharmacist to tell you, or to get your OK first. A study of every state’s law has the details.
It Will Probably Look Different
US trademark law does not let a generic look exactly like the brand, so the color, shape or markings usually change. The active ingredient, strength and form are the same. An “authorized generic,” made by or for the brand’s own company, can look identical. The FDA explains.
Your Insurance May Change Too
Once a lower-cost version is available, many insurance plans charge more for the brand, or stop covering it. Your plan’s drug list (formulary) says how.
Until a generic is on US pharmacy shelves, be careful with websites that offer “generic Prevymis”. The FDA warns that unlicensed online pharmacies sell counterfeit and unapproved medicines; its BeSafeRx page shows how to check a pharmacy.
Questions people ask about Prevymis
Is there a generic for Prevymis right now?
No. As of October 9, 2026 no generic letermovir is listed for sale in the FDA NDC Directory.
When will Prevymis go generic?
February 2033 is the expected month, and that is probable but not certain. It is when Prevymis’s patent 10,603,384 ends. That patent covers the product’s formulation, and once it ends, generics can go on sale as soon as the FDA approves them.
Will generic letermovir be the same as Prevymis?
Yes in the ways that matter: the same active ingredient, strength and form, with proof that it reaches your blood the same way. Inactive ingredients can differ, which is why some people notice a different look or taste.
How much will the generic cost?
Nobody can say for sure before launch. One company has applied to the FDA to make it. In the FDA’s study of past launches, pharmacies paid about 31% less once one company sold a generic. That is a pattern from past launches, not a prediction for this one.
Has the FDA approved a generic Prevymis?
Not yet. The FDA Orange Book lists no approved generic version of Prevymis.
When does the Prevymis patent expire?
The FDA Orange Book lists 2 patents for Prevymis; the last runs to February 2033. The one behind the expected month is patent 10,603,384, which ends in February 2033. A patent date is not the launch date: settlements and court rulings often bring a generic earlier, and FDA approval or a company’s own plans can make it later. The expected month on this page (February 2033) weighs all of that.
Has anyone challenged the Prevymis patents?
Yes. The first patent challenge to Prevymis reached the FDA in October 2024, from one company on that first day. The FDA has not approved a first challenger’s generic yet. A patent challenge (a “Paragraph IV certification”) is a generic company telling the FDA that a patent listed for the brand is invalid or will not be infringed by its version. The first companies to file one can earn a 180-day head start, during which the FDA cannot approve the generics that filed after them.
Changes to This Projection
- First generic expected February 2033 on this month’s schedule. A line is added here whenever a monthly update moves the month, the reason or how sure it is.
Every change to the expected month is logged here with the month we saw it.
Also Going Generic
- SigniforPasireotide DiaspartateDecember 2026
- DutrebisLamivudine and Raltegravir PotassiumSeptember 2029
- IsturisaOsilodrostat PhosphateOctober 2035
- OdomzoSonidegib PhosphateMarch 2036
- AnjesoMeloxicamMarch 2039
- VIZZAceclidine Hydrochloride2041 to 2042
About Prevymis
- Generic name letermovir
- How it is taken Into a vein (IV)
- Company Merck Sharp And Dohme LLC
- Hard to copy Inhalers, injectables, patches and other hard-to-copy products. Fewer companies attempt them and dates slip more often.
- Patent challenges Since October 2024 (FDA)
- More drugs Brand-name drugs starting with P
- Have a question? A pharmacist answers, free. Ask about Prevymis
Sources. The expected month: FDA Paragraph IV Patent Certifications list, federal court records, company announcements and securities filings (settlement dates, launch plans, sales). The record on this page: FDA Orange Book, Drugs@FDA (tentative approvals), FDA NDC Directory, FDA Paragraph IV Patent Certifications list, CMS Medicare Part D Spending by Drug, Medicaid State Drug Utilization Data, FDA, Generic Competition and Drug Prices (2019). Updated October 9, 2026. Information, not medical advice.