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: 0 NAI (no action), 1 VAI (voluntary action), 1 OAI (official action). Leading inspection & GMP sites: United States (2), Czechia (2), Germany (1), Ireland (1).
Last updated 2026-07-17. 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.
What has driven South Korea's rise as a biologics manufacturing hub?
South Korea's biologics CDMO growth (2015-present) has been driven by three factors: (1) Samsung Biologics' massive Songdo capacity build (Plants 1-5 total >600,000L mammalian cell culture, one of the largest single-city concentrations of biologics capacity globally); (2) Celltrion's biosimilar-driven commercial capacity, exported globally; (3) national policy focus on biopharmaceutical export as a strategic industry. Korean CDMOs supplying US and EU markets typically hold MFDS + FDA + EMA certifications concurrently — the Signal Score's Quality Compliance pillar captures all three. For biologics programs specifically, South Korea offers commercial-scale capacity availability that is genuinely scarce in the US and EU.
How do Samsung Biologics and Celltrion compare on CDMO offerings?
Samsung Biologics operates primarily as a contract manufacturer (CDMO) with dedicated commercial biologics capacity at Songdo; Celltrion combines internal biosimilar development with CDMO services, with significant capacity dedicated to their own commercial products. For pure CDMO engagements, Samsung Biologics is typically the more scale-available option; for programs where biosimilar development experience is a plus, Celltrion's integrated model can add value. Both hold FDA and EMA certifications. Cross-check with the biologics CDMO ranking for the broader Korean biologics landscape and individual profile pages for facility-level detail.
South Korean CDMOs supplying US and EU markets — regulatory considerations
South Korean CDMOs supplying US and EU markets need active FDA and EMA GMP certifications on the specific facility. Both regulators have inspection experience with major Korean biologics sites, and inspection outcomes have generally been favorable. For programs supplying UK specifically, post-Brexit MHRA acceptance of MFDS + EMA-recognized inspections has continued under transitional arrangements — sponsors should confirm current MHRA policy at RFP stage. The Signal Score's Quality Compliance pillar captures FDA + EMA + MHRA data directly, so Korean CDMOs with cross-jurisdictional posture rank higher on this pillar than domestic-market-only competitors.
By CDMO Signal's independent Signal Score, the top-ranked Oligonucleotide / ASO CDMOs include ST Pharm. 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 1 Oligonucleotide / ASO CDMO with FDA inspection records and 4 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.