EMA 2004 — Guideline on clinical investigation of medicinal products for psoriasis (CHMP/EWP/2454/02)
Citation
European Medicines Agency, CHMP. Guideline on clinical investigation of medicinal products indicated for the treatment of psoriasis. CHMP/EWP/2454/02 corr., adopted 18 November 2004, in operation June 2005. URL: ema.europa.eu/documents/scientific-guideline/guideline-clinical-investigation-medicinal-products-indicated-treatment-psoriasis_en.pdf
Document type
Regulatory guideline (not a primary study). Sets EU expectations for clinical development of topical and systemic psoriasis treatments; applies to all EU psoriasis drug approvals.
Key endpoints established
- PASI (Psoriasis Area and Severity Index) — recommended primary efficacy variable
- PGA / IGA (Physician / Investigator Global Assessment) — mandatory co-primary endpoint
- BSA (Body Surface Area) — supportive measure
- Response threshold: PASI-75 (historical baseline); PASI-90 acknowledged as high-level therapeutic goal
- HRQoL co-endpoints (DLQI) required to link severity to patient-relevant outcome
Surrogate-to-outcome linkage
Formally anchors PASI and PGA/IGA surrogates to clinically relevant patient outcomes (disease control, HRQoL) via regulator-required co-endpoints. Constitutes the strongest possible form of surrogate endorsement: regulatory acceptance of these scores as proxies for treatment benefit in EU drug approvals.
CRIT1–7 appraisal
| Criterion | Score | Justification |
|---|---|---|
| CRIT1 Relevance | 3 | Direct — codifies the EU regulatory surrogate endpoint for the severity-scoring domain. |
| CRIT2 Methodology | n/a | Guideline (derived from systematic evidence and expert consensus). |
| CRIT3 Reporting | 3 | Formal EMA document with stated endpoint definitions and response thresholds. |
| CRIT4 Applicability | 3 | EU regulatory context directly applicable to the MDR Pillar-1 argument. |
| CRIT5 Evidence weight | 3 | Regulatory guideline — strongest precedent form. |
| CRIT6 Risk of bias | 2 | Dates to 2004; pre-dates IL-17 / IL-23 biologics era where PASI-90 / PASI-100 are standard targets. |
| CRIT7 Contribution | 3 | Foundational regulatory anchor — establishes PASI / IGA as EMA-accepted proxies for patient outcome. |
Aggregate: very strong.
Limitations and notes
Pre-dates modern biologic era; threshold generalisability to AI-generated scores requires additional validation (not a weakness of the guideline — a downstream task). Supplement with HOME (Schmitt 2014) for atopic dermatitis, with Simpson 2016 / King 2022 for pivotal-trial endpoint use.
Strength as anchor
Essential regulatory anchor. The VCA argument for severity scoring as a Pillar-1 surrogate leans on regulator acceptance of PASI / EASI / SCORAD / SALT in drug approvals; this guideline is the formal EU statement for psoriasis. Counterpart for atopic dermatitis is EuroGuiDerm / HOME; for alopecia areata is Olsen 2004 / King 2022; for acne is FDA acne guidance.