Letermovir API Suppliers & Bulk Manufacturers

Available Forms: API (drug substance)

Available Strengths: USP grade or in-house specification

Reference Brands: Prevymis

Category: Active Pharmaceutical Ingredient

Letermovir is a CMV antiviral used in oral and intravenous transplant products. It is sourced by antiviral formulators, CDMOs and generic R&D teams preparing filings.

Product Description:

Letermovir is an antiviral that inhibits the cytomegalovirus (CMV) DNA terminase complex, so the virus cannot package its DNA into new particles. It is approved for prophylaxis of CMV infection and disease in CMV-seropositive recipients of an allogeneic haematopoietic stem cell transplant, and for prophylaxis of CMV disease in high-risk kidney transplant recipients, in adults and in defined paediatric groups (reference brand: Prevymis).

Specification at a glance

Regulatory files and timing

The FDA list of Drug Master Files (third quarter 2026) shows 10 active Type II API DMFs for this molecule. Few filings usually means few qualified sources, so early contact with suppliers pays off. For Europe, ask whether the supplier holds a CEP or an EU ASMF and, for imports into the EU, a written confirmation.

Generic or biosimilar entry. United States: Patent expiry; entry not confirmed (2029). European Union: Patent expiry; entry not confirmed (2029).

Handling and quality points

Letermovir has one stereocentre, so the specification should include chiral purity with a limit for the (R)-enantiomer. Its low water solubility means the solid form and particle size influence dissolution, so confirm whether the material is amorphous or crystalline and how it behaves under heat and humidity. If you plan an intravenous product, check that the supplier can meet endotoxin and bioburden limits suitable for parenteral use.

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Brand names are trademarks of their respective owners and identify the reference medicine only. Information is general and was checked in October 2026; confirm specifications and filings with the supplier before purchase.