EU PAS Register / HMA-EMA Catalogue of Real-World Data Studies

What it is

The EU PAS Register (EU Post-Authorisation Study Register) is a free, publicly searchable registration platform for non-interventional post-authorisation studies of authorised medicines, launched in November 2010 by the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance (ENCePP) under European Medicines Agency (EMA) coordination. In February 2024 it was decommissioned and replaced by the HMA-EMA Catalogues of real-world data sources and studies — a paired system in which the studies catalogue (the EU PAS Register's successor) holds study records and links each one to entries in the companion data sources catalogue. Throughout, the platform is a transparency container: it records that a study exists, its objectives, design, data sources, milestones, protocol, amendments, and results — it does not appraise, score, or certify methodological quality. It is governed alongside the ENCePP Code of Conduct and the ENCePP Guide on Methodological Standards in Pharmacoepidemiology, which supply the methods substance the register itself does not.

When to use

Register a study here when it is a non-interventional / observational study of an authorised medicine in the EU regulatory ecosystem. Registration is a legal obligation for imposed PASS (post-authorisation safety studies required as a condition of marketing authorisation, under Good Pharmacovigilance Practices Module VIII) and is strongly expected for voluntary PASS, drug-utilisation studies, and effectiveness/safety RWE intended for EU regulatory interaction, ENCePP study status, the ENCePP Seal, or transparency-driven publication. Decision rules for picking the right registry: interventional clinical trials go to CTIS (EU Clinical Trials Regulation; legacy EudraCT) or ClinicalTrials.gov, not here; systematic reviews / meta-analyses go to PROSPERO; this platform is for primary observational and real-world data studies. Post-February 2024, register new studies in the HMA-EMA Catalogue of real-world data studies and link the study record to the database's entry in the data-sources catalogue; do not attempt to register in the retired EU PAS Register or cite dead `encepp.eu/encepp/studiesDatabase.jsp` links.

What it requires

The platform enforces fields and timing, not analytic content. At registration it captures study identification, research question and objectives, design, study population, exposures/outcomes of interest, the data source(s), planned methods, sponsor/funding, and milestones; for imposed PASS the agreed protocol must be posted before data collection starts, with substantial amendments, progress, and the final study report or results posted as they occur. The post-2024 catalogue adds the requirement to link the study to a registered real-world data source, reinforcing data-provenance transparency. Framed for real-world data work, the register operationalises design transparency (prospective, time-stamped posting of objectives, design, and analysis intentions before results are known) and data-fitness traceability (an auditable link from the study to the database it used). It does not itself mandate phenotype/algorithm validation, time-zero alignment, estimand specification, confounding control, or quantitative bias analysis — those are the substance the registrant supplies, governed by the ENCePP Guide, GVP Module VIII, HARPER, and STaRT-RWE, and implemented through the catalog concepts mapped below.

When NOT to use — limitations and common misapplications

The single most consequential error is treating registration as a quality or validity guarantee: the register is not a reporting checklist (use STROBE / RECORD-PE), not a protocol template (use HARPER / STaRT-RWE), and not a risk-of-bias instrument (use ROBINS-I / the ENCePP Checklist). A registered protocol can still be a poorly designed, confounded, immortal-time-ridden observational study — registration does not make a study causal. Other failure modes:

1. confusing registration with the ENCePP Seal — the Seal signals adherence to the ENCePP Code of Conduct and is a separate, additional step;
2. retrospective registration after results are known, which defeats the anti-selective-reporting purpose and still permits outcome switching;
3. wrong registry — entering an RCT (belongs in CTIS) or a systematic review (belongs in PROSPERO);
4. registration-as-theater — posting a thin record to satisfy an obligation while the substantive protocol, amendments, or results are never completed or updated;
5. stale-platform citation — referencing the retired EU PAS Register or its old ENCePP URLs after the February 2024 migration to the HMA-EMA Catalogue.

How it maps to this catalog

The register is the transparency wrapper; these concepts implement what actually goes inside each field. Objectives / PICOTS and protocol scaffolding -> `picots-framework-rwe`, `study-protocol-or-sap-elements`. Design, time-zero, and a defensible comparator -> `target-trial-emulation`, `active-comparator-new-user`, `time-zero-index-date-alignment-rwe`. Data-source fitness (the link to the data-sources catalogue) -> `fit-for-purpose-data-assessment-rwe`, `claims-analysis`, `regulatory-readiness-rwe`. Outcome/exposure operational definitions and phenotype validation -> `diagnosis-phenotype-algorithm-1ip-2op-time-window-rwe`, `claims-outcome-algorithm-ppv-sensitivity-rwe`. Confounding control -> `high-dimensional-propensity-score-hdps-rwe`, `propensity-score-methods-psm-iptw`. Estimands and intercurrent events -> `estimands-ate-att-intercurrent-events-rwe`. Attrition and results reporting -> `attrition-and-loss-to-follow-up-rwe`, `database-feasibility-attrition-funnel-rwe`. Sensitivity / quantitative bias analysis -> `e-value-sensitivity-analysis`, `quantitative-bias-analysis-toolkit-rwe`.

Applied note (claims / EHR / registry RWE)

For a US-claims or EHR study registered for EU regulatory or transparency purposes, create the study record and link it to the database's entry in the HMA-EMA data-sources catalogue; where a US source (Medicare FFS, commercial, or an EHR network) has sparse or absent catalogue metadata, carry provenance explicitly through a `fit-for-purpose-data-assessment-rwe` write-up rather than leaning on the catalogue entry. Pair registration with HARPER or STaRT-RWE for the protocol you post, and RECORD-PE for the eventual report — the register fixes that and when, those guidelines fix what and how well.

Citations

1. [1]HMA-EMA Catalogues of real-world data sources and studies. Heads of Medicines Agencies (HMA) and European Medicines Agency (EMA), 2024 (successor to the EU PAS Register, launched by ENCePP/EMA in 2010).
2. [2]Sultana J, Crisafulli S, Almas M, et al. Overview of the European post-authorisation study register post-authorization studies performed in Europe from September 2010 to December 2018. Pharmacoepidemiology and Drug Safety. 2022;31(8):823-835.
3. [3]ENCePP Guide on Methodological Standards in Pharmacoepidemiology (Revision 11). European Network of Centres for Pharmacoepidemiology and Pharmacovigilance, 2023.

1. [4]Wang SV, Pottegård A, Crown W, et al. HARmonized Protocol Template to Enhance Reproducibility of hypothesis evaluating real-world evidence studies on treatment effects: A good practices report of a joint ISPE/ISPOR task force (HARPER). Pharmacoepidemiology and Drug Safety. 2023;32(1):44-55.
2. [5]Wang SV, Pinheiro S, Hua W, et al. STaRT-RWE: structured template for planning and reporting on the implementation of real world evidence studies. BMJ. 2021;372:m4856.