How to Choose a CDMO

The first filter in any CDMO selection is technical fit at the modality level — not general capability, but actual GMP experience on your specific vector, cell type, dosage form, or molecule class. A CDMO that runs biologics well doesn't necessarily run AAV well; an AAV CDMO doesn't automatically handle lentivirus; a small-molecule CDMO with strong solid dosage capability may not have qualified sterile injectable lines. Modality experience compounds — a CDMO that has manufactured for 20 AAV programs has qualified assay platforms, established process-development playbooks, and inspection history that a first-time AAV CDMO cannot match at any price.

How to filter: start with the modality directory. Every CDMO tagged in a modality has confirmed capability in that class. For combined-modality programs (e.g. lentiviral vector supply + downstream cell therapy), look for CDMOs appearing on both modality pages — the integrated candidates worth prioritizing for combined-scope RFPs.

Second filter is the regulatory posture of the specific site where the program will run — not the CDMO's aggregate record. Sponsors routinely make the mistake of shortlisting on the CDMO's company-level FDA record when the planned site has its own distinct inspection history. Inspections are facility- and process-scoped: a CDMO with a strong record at their US site may have unresolved issues at their EU site, or on their AAV suite versus their mAb suite.

The signals that matter: (1) most recent FDA Establishment Inspection Report classification — NAI (No Action Indicated), VAI (Voluntary Action Indicated), or OAI (Official Action Indicated); OAI is a disqualifier for most commercial programs. (2) Number and severity of Form 483 observations issued at the site over the last 5 years. (3) Any FDA Warning Letters — a Warning Letter is a hard signal of unresolved compliance issues and typically excludes the site from commercial supply until resolved. (4) EMA + MHRA GMP certificate coverage for the specific manufacturing activity (drug substance vs drug product, and the specific dosage form). CDMO Signal's Quality Compliance pillar (35% of the composite Signal Score) captures all four signals — but for a specific program selection, drill into the site-level detail on the individual CDMO profile page.

Third filter is capacity. Two common failure modes: (a) shortlisting a commercial-scale CDMO for early clinical work and paying commercial-scale prices for the flexibility; (b) shortlisting a clinical-scale CDMO and discovering at Phase 2/3 they can't scale to commercial supply, forcing a late-stage tech transfer that adds 6-12 months and $10-30M in comparability work. Match capacity to your target dose × patient volume × program phase, and confirm commercial-scale readiness at RFP if there's any path to Phase 3.

Filter by capacity class using the platform's capacity-tier filters where available (e.g. /modality/aav/commercial-scale). Then verify at RFP: (1) actual batch sizes the site can run today, not designed capacity; (2) slot availability at your target timeline — commercial CDMOs are booked 18-24 months out for high-demand modalities; (3) headroom for scale-up over your program's expected commercial lifetime, so you're not renegotiating capacity mid-launch.

Fourth filter is CDMO financial health — an under-appreciated risk that surfaces catastrophically when it hits. A CDMO in financial distress cuts investment in analytics, cannot retain senior staff, defers capex on the sites you're using, and in the worst case files for bankruptcy protection mid-program. Supply continuity risk destroys clinical timelines; a Phase 3 program with a distressed CDMO is a genuine crisis.

Signals to watch: (1) parent-company SEC filings for public CDMOs (10-K, 10-Q, 8-K disclosures — the Signal Score's Financial Stability pillar draws from SEC EDGAR directly for public parents); (2) rating agency actions on parent debt; (3) recent leadership turnover, particularly CFO or Quality/Regulatory heads; (4) capex trajectory — cutting facility investment is a leading indicator; (5) monitored press signals for site closures, layoffs, or restructuring events. Private CDMOs are harder to evaluate — for critical programs, request their most recent audited financials at RFP as a condition of shortlisting.

Fifth filter is often the true differentiator once the top three or four candidates pass the first four gates: how much of your process the CDMO can accept as-is versus how much they'll demand change. Tech transfer costs compound in every dimension — analytics revalidation, comparability studies, regulatory amendments, and the timeline drag of running two processes in parallel while the transfer completes. A CDMO with a flexible platform that accepts non-native process elements de-risks the entire engagement.

Signals to probe at RFP: (1) how many programs they've onboarded in the last 24 months where the sponsor arrived with a locked process — good CDMOs have a real number; (2) their historic "process change requested at onboarding" rate — some CDMOs quietly force major changes that add months; (3) their analytics platform match to yours — if they have your titer / potency / release assays already qualified, comparability work compresses; (4) their tech-transfer methodology documentation — mature CDMOs have this codified, immature CDMOs improvise per program.

Filter in the layer order above, not in parallel. Sponsors who evaluate on price or geography first end up disqualifying strong candidates on secondary criteria and shortlisting weak candidates whose regulatory record they haven't checked. The technical + regulatory match is a gate — either the CDMO can safely run your program or they can't. Only among CDMOs that pass gates 1-3 does capacity fit become the differentiator; only among those that pass 1-4 does financial stability separate options; and tech-transfer readiness is what closes the choice among the final 2-3 candidates.

CDMO Signal's composite Signal Score is designed to support this filter order. The four pillars — Quality Compliance (35%), Operations (25%), Financial Stability (20%), Capacity Intelligence (20%) — weight regulatory and operational depth heavily, exactly because these are the gates most sponsors mis-order. Use the score to compress your shortlist; use RFP diligence to close the final choice.