ICH E3 guideline on Structure and Content of Clinical Study Reports (ICH E3)

ICH E3 is an international harmonised tripartite guideline that sets a common structure for clinical study reports used in Europe, Japan and the United States. It was developed by the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Expert Working Group and reached Step 4 (final) on 30 November 1995. Its purpose is to enable a single core clinical study report for therapeutic, prophylactic and diagnostic studies, especially efficacy and safety trials, that can be accepted across all ICH regions. It guides sponsors and investigators on how to present methods, results and patient‑level data in a clear, consistent format that supports regulatory review and replication of key analyses.
Objective: single core clinical study report acceptable to regulators in Europe, Japan and the United States, with any regional requirements added as appendices.
Focus: efficacy and safety trials, with a structure that can be adapted to other clinical studies such as clinical pharmacology.
Aim: reports that are complete, unambiguous, well organised and easy to review, with enough patient‑level and methodological detail to replicate key analyses.

Structure and main content
Defines an integrated report combining clinical and statistical text, tables and figures with standardised appendices (protocol, sample case report forms, investigator and product information, statistics and patient data listings).
Permits abbreviated reports for certain non‑pivotal or flawed studies, while still requiring a full safety description and sufficient design and results information for regulatory assessment.

Sections 1–8 cover front matter and context: title page, synopsis, contents, abbreviations, ethics and informed consent, study team and governance, introduction and objectives.

Methods and results
Section 9 (Investigational plan) explains how to describe study methods: design and control groups, population, treatments, randomisation and blinding, dosing, concomitant therapies, endpoints, data quality and planned statistics, including any changes made after study start.
Sections 10–11 cover reporting of patients and efficacy: disposition and protocol deviations, analysis data sets, baseline characteristics, treatment compliance and efficacy outcomes, with guidance on primary endpoints, missing data and key analyses (for example multicentre or subgroup).

Safety and conclusions
Section 12 (Safety evaluation) sets out how to present safety: exposure, common adverse events and laboratory changes, and serious or other significant adverse events leading to withdrawal or dose change, plus formats for summaries, patient‑level listings and narratives.
Section 13 (Discussion and overall conclusions) provides a concise interpretation of efficacy and safety, risk–benefit and major findings, including implications for at‑risk groups and future studies.

Supporting material
Section 14 contains summary tables, figures and graphs referenced in the text; Section 15 lists references.
Section 16 describes appendices for study documents, patient‑level listings and, where required, full individual patient data; annexes give example layouts for synopses, study design and assessment schedules, patient disposition and key listings that can be adapted locally.