Romiplostim Drug Substance Suppliers & Bulk Manufacturers

Available Forms: Drug substance (bulk)

Available Strengths: Supplied to an in-house or pharmacopoeial specification

Reference Brands: Nplate

Category: Active Pharmaceutical Ingredient

Romiplostim is an Fc-peptide fusion protein that stimulates platelet production. Its drug substance is sought by biosimilar developers, biologics CDMOs and R&D teams.

Product Description:

Romiplostim is a thrombopoietin receptor agonist built as an Fc-peptide fusion protein, or peptibody: each of its two chains joins a human IgG1 Fc domain to a peptide that binds and activates the thrombopoietin receptor, raising platelet production. It is approved for immune thrombocytopenia in adults and in children aged 1 year and older who have not responded well enough to other treatments, and in the US also to improve survival after acute exposure to myelosuppressive doses of radiation (reference brand: Nplate).

Specification at a glance

Regulatory files and timing

Biologic drug substance is usually supplied in bulk under a long-term supply agreement, or licensed together with the dossier, rather than bought as a one-off API order. Buyers typically ask for the drug substance comparability package, cell bank and process documentation, and the supplier's GMP status.

Generic or biosimilar entry. United States: Patent expiry; entry not confirmed (Feb 2028). European Union: Patent expiry; entry not confirmed (Apr 2027).

Handling and quality points

Because romiplostim is made in E. coli, it is not glycosylated and has to be refolded with correct disulfide bonds, so host-cell protein, endotoxin, misfolded variants and aggregates are the main quality points. The drug substance needs cold-chain storage and transport at controlled temperature, with attention to freeze-thaw and agitation. Oxidation and deamidation variants should be monitored on stability, and potency is confirmed with a cell-based receptor activation assay.

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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.