Nusinersen Sodium API Suppliers & Bulk Manufacturers

Available Forms: API (drug substance)

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

Reference Brands: Spinraza

Category: Active Pharmaceutical Ingredient

Nusinersen is an antisense oligonucleotide supplied as its sodium salt for intrathecal products. It is sourced by oligonucleotide formulators, CDMOs and R&D teams.

Product Description:

Nusinersen is an antisense oligonucleotide that binds to SMN2 pre-messenger RNA and changes how it is spliced, so that cells make more full-length survival motor neuron (SMN) protein. It is approved for the treatment of spinal muscular atrophy in children and adults, and in the EU specifically for 5q spinal muscular atrophy (reference brand: Spinraza).

Specification at a glance

Regulatory files and timing

The FDA list of Drug Master Files (third quarter 2026) shows 9 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 (Dec 2030 (compound patent)). European Union: No confirmed date.

Handling and quality points

Nusinersen is made by solid-phase phosphoramidite synthesis and chromatographic purification, so the impurity profile is dominated by closely related oligonucleotides: shorter and longer sequences, and species where a phosphorothioate has become a phosphodiester. Each phosphorothioate linkage is a stereocentre, so the product is a diastereomer mixture and the supplier's process should give a consistent profile. As the finished product is given intrathecally, endotoxin and bioburden limits are tight, and the hygroscopic powder needs moisture-protected packing and controlled storage.

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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.