Best Oligonucleotide / ASO CDMOs in United States
· updated as new inspection, certificate, and trial data enters the platform
12
CDMOs tracked
12
Fully scored
5
With FDA records
14
FDA inspections
29
EMA/MHRA GMP certs
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: 8 NAI (no action), 5 VAI (voluntary action), 1 OAI (official action). Leading inspection & GMP sites: United States (12), Spain (10), Italy (9), France (4), Portugal (4).
Last updated 2026-07-23. Sourced from FDA, EMA EudraGMDP, MHRA GMDP, and ClinicalTrials.gov.
| # | CDMO | Signal Score | Quality | FDA · GMP | Capacity | Programs |
|---|---|---|---|---|---|---|
| 1 |
AL
Agilent Technologies (Oligo GMP)
Santa Clara, CA
|
74.2 | 100.0 | 2 insp · 0 GMP | — | 1 programs |
| 2 |
AJ
Ajinomoto Bio-Pharma Services
San Diego, CA · Osaka, JP
|
83.5 | 100.0 | 0 insp · 1 GMP | — | 0 programs |
| 3 |
CD
Corden Pharma
Plankstadt, DE · Caponago, IT · Boulder, CO
|
81.1 | 98.9 | 4 insp · 10 GMP | — | 0 programs |
| 4 |
ND
Nitto Denko Avecia
Milford, MA
|
80.3 | 100.0 | 3 insp · 0 GMP | — | 0 programs |
| 5 |
CRA
Curia (RNA/Advanced)
Albany, NY · Albuquerque, NM
|
79.4 | 99.9 | 2 insp · 18 GMP | — | 0 programs |
| 6 |
TL
TriLink BioTechnologies
San Diego, CA
|
71.0 | — | — | — | 0 programs |
| 7 |
PP
PolyPeptide Group
Torrance, CA · Strasbourg, FR · Malmo, SE
|
66.1 | 74.2 | 3 insp · 0 GMP | — | 0 programs |
| 8 |
LG
LGC Biosearch Technologies
Petaluma, CA · Middleton, WI
|
63.0 | — | — | — | 0 programs |
| 9 |
BS
Bio-Synthesis Inc.
Lewisville, TX
|
56.5 | — | — | — | 0 programs |
| 10 |
CG2
ChemGenes Corporation
Wilmington, MA
|
56.5 | — | — | — | 0 programs |
| 11 |
MM
Mermade (BioAutomation)
Irving, TX
|
56.5 | — | — | — | 0 programs |
| 12 |
GR
Glen Research
Sterling, VA
|
56.5 | — | — | — | 0 programs |
What to evaluate in a Oligonucleotide / ASO CDMO
Synthesis scale
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.
FDA jurisdiction — how the ranking scores US-based CDMOs
The Signal Score's Quality Compliance pillar (35% of the composite) is dominated by FDA inspection data for US-based CDMOs: Establishment Inspection Report classifications (NAI, VAI, OAI), Form 483 observation counts, and Warning Letter history. For a CDMO whose primary facility footprint is US, this pillar carries direct weight — an inspection on the site slated for a sponsor's program applies without translation. For CDMOs with mixed US + international facility footprint, the ranking reflects the composite regulatory posture; sponsors evaluating for a specific program should verify inspection history on the exact US site under consideration via that CDMO's profile page.
Which US CDMOs also cover EU and UK regulatory geographies?
Many top-tier US-based CDMOs maintain EU (EMA) and UK (MHRA) GMP certification for facilities used to supply EU and UK trials or commercial markets. The Signal Score's Quality Compliance pillar includes EMA + MHRA certificate density as a component — a US-headquartered CDMO with dense EU/UK certificates typically ranks higher on this pillar than a US-only competitor. Sponsors running dual-jurisdiction programs should cross-check the individual CDMO profile pages for specific certificate coverage; the Europe region ranking surfaces CDMOs that also appear in the European jurisdiction ranking, indicating multi-region regulatory posture.
How CDMO Signal identifies US manufacturing presence
Region attribution is derived from each CDMO's declared facility locations in our directory. A CDMO's facility list is validated against corporate filings, press releases, and — where public — the FDA facility registration (FEI number lookups). Region matching is done at the country level: a US state name or two-letter abbreviation in the facility list places the CDMO in the US region. CDMOs with US + international sites appear in every applicable region ranking, which reflects operational reality — such a CDMO is a legitimate candidate for programs in any of those jurisdictions.
Oligonucleotide / ASO CDMOs — Frequently Asked Questions
Who are the top Oligonucleotide / ASO CDMOs?
By CDMO Signal's independent Signal Score, the top-ranked Oligonucleotide / ASO CDMOs include Agilent Technologies (Oligo GMP), Ajinomoto Bio-Pharma Services, Corden Pharma. 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 5 Oligonucleotide / ASO CDMOs with FDA inspection records and 29 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.
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