What is ICH E3?
ICH E3, Structure and Content of Clinical Study Reports, is the international guideline for writing a clinical study report (CSR): the full, integrated report of an individual clinical study of a therapeutic, prophylactic or diagnostic agent. The ICH guideline reached Step 4 on November 30, 1995, and aims for a single core report acceptable to all ICH regions. It mainly targets efficacy and safety trials, but its principles extend to other studies such as clinical pharmacology studies.
Current status: is there a newer version?
As of October 2026, the version in force is still the 1995 guideline plus the E3 Questions and Answers (R1), July 2012. The EMA page lists the Step 5 version (CPMP/ICH/137/95) with a legal effective date of July 1, 1996, and FDA lists E3 as guidance for industry. We found no published E3 revision.
Searches for “ICH E3 R3” or “ICH R6 E3” usually mean ICH E6(R3), the Good Clinical Practice guideline that FDA published in final form in September 2025. E6 governs how trials are run; E3 governs how a completed study is reported.
E3 is a guideline, not a template
The 2012 Q&A is explicit: “ICH E3 is a Guideline, not a set of rigid requirements or a template.” Sponsors may reorder, rename, delete or add sections without giving a rationale, but if a relevant E3 aspect is not addressed, the report should say so and why. Topics E3 does not cover, such as pharmacokinetics, biomarkers or patient-reported outcomes, can get new headings or separate reports placed alongside the main CSR in the eCTD.
The 16 sections of an ICH E3 clinical study report
| # | Section | What it contains |
|---|---|---|
| 1 | Title page | Study identification, sponsor, dates, GCP statement |
| 2 | Synopsis | Stand-alone summary with numerical results |
| 3 | Table of contents | Including appendices and tables |
| 4 | Abbreviations and definitions | Terms used in the report |
| 5 | Ethics | IEC/IRB, ethical conduct, informed consent |
| 6 | Investigators and administrative structure | Who ran the study |
| 7 | Introduction | Context and rationale |
| 8 | Study objectives | Primary and secondary objectives |
| 9 | Investigational plan | Design, population, treatments, endpoints, data quality, statistical methods, changes |
| 10 | Study patients | Disposition and protocol deviations |
| 11 | Efficacy evaluation | Data sets, demographics, compliance, efficacy results |
| 12 | Safety evaluation | Exposure, adverse events, deaths, SAEs, labs, vital signs |
| 13 | Discussion and overall conclusions | Interpretation |
| 14 | Tables, figures and graphs | Referred to but not in the text |
| 15 | Reference list | Literature cited |
| 16 | Appendices | Study information and patient data listings |
Synopsis length
E3 says the synopsis is “usually limited to 3 pages” and should include numerical data, not only text or p-values. The Q&A adds that the synopsis must stand alone without cross-references and that the 10-page example in ICH M4E is not an absolute limit.
Protocol deviations (Section 10.2)
Important deviations related to inclusion or exclusion criteria, study conduct, patient management or patient assessment must be described. The report body summarizes them by centre and category, such as patients entered without meeting criteria or given the wrong treatment or dose, and individual patients are listed in appendix 16.2.2.
Narratives (Section 12.3.2)
Brief narratives are required for each death, each other serious adverse event, and other significant adverse events of special interest. Each covers the event’s nature and intensity, clinical course, relevant laboratory results, whether the drug was stopped, countermeasures, post-mortem findings, and the investigator’s and sponsor’s causality opinions.
Appendix 16.1
The study-information appendix includes the protocol and amendments (16.1.1), sample CRF (16.1.2), IEC/IRB and consent information (16.1.3), investigator list (16.1.4), signatures (16.1.5), randomization scheme (16.1.7), audit certificates (16.1.8), documentation of statistical methods (16.1.9) and other supporting items. The Q&A says documents needed to review the CSR, such as the protocol and statistical methods, belong in the appendices even if they are also in the Trial Master File.
CSR submission and disclosure in 2026
eCTD placement. CSRs sit in Module 5 of the Common Technical Document. FDA’s eCTD guidance places the integrated summaries of efficacy and safety in section 5.3.5.3, alongside the individual study reports in Module 5.3.
US results disclosure. On April 13, 2026, FDA said it had contacted more than 2,200 sponsors and researchers about more than 3,000 trials that appeared not to have posted required results to ClinicalTrials.gov, citing an internal analysis that 29.6% of studies likely subject to mandatory reporting had no results posted. Results postings, protocols and SAPs are public, so they must match what the CSR reports.
EU. Under the Clinical Trials Regulation, sponsors must submit a summary of results and a layperson summary to CTIS within one year of the end of the trial in all Member States, regardless of outcome.
Common weaknesses
- Synopsis that relies on cross-references or omits numbers.
- Protocol deviations summarized without the categories and patient listings E3 expects.
- Narratives missing laboratory data, countermeasures or causality opinions.
- CSR results that differ from ClinicalTrials.gov postings or the SAP’s pre-specified analyses, without explanation.
- Estimands described differently in the CSR than in the protocol and SAP.
- Sections removed without stating that the topic is not relevant.
Checklist: CSR review against ICH E3
- Every E3 topic is covered, or its omission is explained
- Synopsis stands alone and includes numerical results
- Analyses match the final SAP; post hoc analyses are labeled
- Protocol deviations summarized by category and listed in 16.2.2
- Narratives cover all deaths, SAEs and events of special interest with required elements
- Appendix 16.1 includes protocol, amendments and statistical methods documentation
- Numbers in text, tables and synopsis agree
- Results consistent with ClinicalTrials.gov and EU CTIS summaries
How AskDona helps
A CSR is assembled from the protocol, SAP, tables, listings and figures, safety narratives and many authors. AskDona reads the CSR alongside those sources, checks each section against ICH E3 and the Q&A, and flags numbers, deviations or estimands that do not match, citing the page and table. Run a sample CSR consistency check against protocol, SAP and TLFs before your next quality review. AskDona shows the evidence; your medical writing and biostatistics teams decide.
Editor’s note: ICH E3 content comes from the ICH-hosted guideline and 2012 Q&A. The “no revision” statement reflects the ICH, EMA and FDA pages checked and searches we ran; ICH’s work plan can change. The EU summary-of-results rule is quoted from the Dutch CCMO’s guidance on the CTR rather than the regulation text itself.
FAQ
What is ICH E3? The ICH guideline on the structure and content of clinical study reports, finalized in 1995 and supplemented by a 2012 Q&A.
What is a clinical study report (CSR)? The full, integrated report of an individual clinical study, covering methods, results, efficacy, safety and conclusions, submitted to regulators.
How long should an ICH E3 synopsis be? E3 says usually up to 3 pages. The Q&A notes it must stand alone and that the M4E 10-page example is not an absolute limit.
Is ICH E3 a template? No. The Q&A says it is a guideline, not rigid requirements or a template; sections can be reordered, renamed, added or deleted.
Has ICH E3 been revised? Not as of October 2026. The 1995 guideline and the 2012 Q&A (R1) remain current. “E3 R3” searches usually mean E6(R3) on GCP.
Where does a CSR go in the eCTD? Module 5, under clinical study reports.
References
All pages opened and checked by October 19, 2026.
| Source | Type | Used for |
|---|---|---|
| ICH E3 guideline | Regulatory guideline | Sections, synopsis, deviations, narratives, appendices |
| ICH E3 Q&As (R1) | Regulatory guideline | Flexibility, synopsis, appendices |
| EMA ICH E3 page | Regulator | EU status and effective date |
| FDA E3 guidance page | Regulator | US status |
| FDA ISS/ISE placement | Regulator | eCTD Module 5 |
| FDA press release, Apr 13, 2026 | Regulator | Results disclosure push |
| CCMO: Summary of results (CTR) | National competent authority body | EU one-year rule |