Summaries of clinical trial results for laypersons

Good Lay Summary Practice (GLSP) is a European Commission guidance document that explains how sponsors should plan, develop, translate and disseminate lay summaries of clinical trial results to meet the transparency obligations in Clinical Trials Regulation (EU) No. 536/2014. Its purpose is to ensure that trial participants and the wider public receive accurate, balanced and understandable information about trial outcomes, including benefits and risks.
GLSP is structured in two parts: a concise Quick Guide and a detailed Handbook with annexes.
Quick Guide: summarises key recommendations and process steps, giving an overview of good lay summary practice and the four‑step process (planning, development, translation, dissemination).
Handbook: provides in‑depth guidance, examples and supporting tables, including effort estimates, writing examples, recommendations for paediatric lay summaries and supplemental appendices.The main guidance is organised around four steps in the lay summary process:
Planning: covers standard operating procedures, templates, budgeting and timelines aligned with protocol and trial documents, early patient involvement, and coordination between sponsors, investigators and other stakeholders.
Development: explains how to address the ten mandatory Annex V content elements (trial identification, sponsor contact details, general trial information, participant population, investigational medicinal products, adverse reactions and risks, overall results, sponsor’s comments, follow‑up trials, additional information sources). It sets out plain‑language principles (non‑technical language, short sentences, avoiding jargon and Latin expressions, clear numeracy, health literacy), and gives recommendations on layout, design, accessibility and user testing with non‑experts.
Translation: outlines strategies for consistent, high‑quality translation, including use of glossaries and style guides and coordination when multiple languages are needed.
Dissemination: emphasises the requirement to upload lay summaries to the Clinical Trials Information System within defined timelines (typically 12 months after trial end for adult trials, 6 months for paediatric trials, and up to 30 months for non‑therapeutic Phase 1), and describes optional additional dissemination routes (for example via investigators, printed copies or websites) in a non‑promotional manner.

For investigator‑initiated clinical studies of medicinal products conducted in the EU/EEA, GLSP offers a practical framework to meet the legal requirement to prepare lay summaries under Article 37 of the Clinical Trials Regulation, including process design, templates and review procedures. A pragmatic way to use the guidance is to start with the Quick Guide for an overview of the four steps, then apply the detailed recommendations in the Handbook to build or refine internal standard operating procedures, templates and user testing approaches.

GLSP was developed by the Clinical Trials Expert Group in cooperation with the Roadmap Initiative to Good Lay Summary Practice, drawing on experience and recommendations from more than 60 organisations from industry, academia, patient groups and non‑profit sectors.