Oligonucleotide CDMOs make antisense oligonucleotides (ASOs), siRNAs, and related nucleic-acid drugs by solid-phase synthesis, with downstream purification and conjugation (e.g. GalNAc). The segment has grown sharply alongside approved ASO and siRNA therapeutics.
Choosing an oligonucleotide CDMO turns on synthesis scale, chemistry breadth (phosphorothioate backbones, 2'-modifications, conjugation), purity, and a clean regulatory record. The rankings below score each CDMO on FDA inspections, GMP certification, clinical activity, and capacity.
FDA inspection outcomes across these CDMOs: 2 NAI (no action), 8 VAI (voluntary action), 1 OAI (official action). Leading inspection & GMP sites: United States (7), Germany (4), Italy (4), Belgium (4), Portugal (4).
Last updated 2026-08-14. Sourced from FDA, EMA EudraGMDP, MHRA GMDP, and ClinicalTrials.gov.
Match synthesizer scale (mmol to mol) to your clinical and commercial demand, and confirm the CDMO can scale without shifting the impurity profile.
Chemistry & conjugation
Confirm experience with your backbone and modifications (phosphorothioate, 2'-MOE/F) and any conjugation (GalNAc, lipid) your molecule requires.
Purity & analytics
Full-length product, deletion/addition impurities, and residual metals drive release. Look for established orthogonal analytics.
Regulatory track record
Cross-check FDA 483 history and EMA/MHRA GMP coverage — both shown above and on each profile.
EMA and MHRA regulatory considerations for European-manufactured programs
European manufacturing for biopharma programs typically requires EMA-recognized GMP certification (via the EudraGMDP database) for EU material and MHRA GMP certification for UK material — post-Brexit, these are separate credentials even for CDMOs operating in both. The Signal Score's Quality Compliance pillar weighs EMA + MHRA GMP certificate density directly, so European CDMOs with dense certification typically rank higher on this pillar. Sponsors should verify certificate coverage for the specific manufacturing activity (drug substance vs drug product, dosage form) at the specific facility being considered — GMP certificates are activity-scoped, not blanket.
QP release requirements and how they affect CDMO selection
Every batch of medicinal product supplied to the EU market must be released by a Qualified Person (QP) — a specific regulatory role with statutory responsibility. This adds a process step (and typically a specific QP-service arrangement) that US-only manufacturing does not require. CDMOs with European operations either have in-house QPs (typical for larger diversified players) or coordinate with external QP services. For sponsors running EU trials or supplying EU commercial markets, this is a non-negotiable requirement to plan for. Individual CDMO profile pages capture facility-level detail; QP arrangements specifically are usually confirmed at RFP stage rather than published.
Which European CDMOs also cover FDA (US) regulatory geography?
European CDMOs with US FDA inspection history — indicating US regulatory posture — are candidates for sponsors running programs in both jurisdictions. The Signal Score's Quality Compliance pillar includes FDA inspection classifications, so a European CDMO with a strong FDA record typically ranks higher on that pillar than a European-only competitor. Cross-check with the US region ranking — CDMOs appearing in both rankings have demonstrated regulatory posture across both jurisdictions, which reduces tech-transfer risk for global programs.
By CDMO Signal's independent Signal Score, the top-ranked Oligonucleotide / ASO CDMOs include Axolabs (Nuvisan), Corden Pharma, Kaneka Eurogentec. See the full ranked table above — scored on FDA, clinical, financial, and capacity data.
How many Oligonucleotide / ASO CDMOs have FDA inspection records?
CDMO Signal tracks 4 Oligonucleotide / ASO CDMOs with FDA inspection records and 14 EMA/MHRA GMP certificates across the group.
What should I look for in an oligonucleotide CDMO?
Match synthesis scale to your demand, confirm experience with your backbone chemistry and any conjugation (e.g. GalNAc), prioritize strong purity analytics, and a clean FDA and EMA/MHRA record.
What therapeutics do oligonucleotide CDMOs make?
Antisense oligonucleotides (ASOs), siRNAs, aptamers, and related nucleic-acid drugs — increasingly with conjugation chemistries like GalNAc for targeted delivery.