'Femi Fajimi

Understanding the ICH Guidelines: E3, E6, and E8 from a Medical Writer’s Perspective 

By ‘Femi Fajimi | 05 May 2025 

Becoming confident in regulatory medical writing involves more than understanding clinical content; it also means becoming familiar with the guidelines that shape how studies are conducted and reported. 

The International Council for Harmonisation (ICH) issues globally recognised standards that ensure the ethical and scientific quality of clinical trials. Several ICH guidelines are particularly relevant to medical writers, but three form a strong foundation for everyday work: E3, E6, and E8. 

Each one serves a different purpose, depending on the clinical trial stage and the type of document being prepared. Here’s a brief overview from the perspective of a writer. 

ICH E3 – Structure and Content of Clinical Study Reports (CSRs) 

What it is: 

ICH E3 provides a standard format for writing Clinical Study Reports. It outlines the key sections, appendices, and safety and efficacy data presentation required for regulatory submissions. 

Why it matters to writers: 

• Used when drafting or reviewing a CSR 

• Ensures consistency and completeness across submissions 

• Helps make complex data easier to interpret for regulatory reviewers 

Following E3 supports clarity, traceability, and submission readiness. 

ICH E6 (R2) – Good Clinical Practice (GCP) 

What it is: 

This guideline defines the ethical and scientific standards for conducting clinical trials. It applies to all aspects of trial planning, conduct, and reporting. 

Why it matters to writers: 

• Influences protocols, CSRs, ICFs, and IBs 

• Shapes how we document data collection, participant rights, and safety oversight 

• Supports objective, factual, and compliant communication 

GCP is the foundation for all well-documented, ethically sound trial materials. 

ICH E8 – General Considerations for Clinical Studies 

What it is: 

E8 outlines broader principles for clinical trial design and quality. It encourages studies to be fit-for-purpose, participant-focused, and scientifically valid. 

Why it matters to writers: 

• Shapes the rationale, objectives, and design sections in protocols 

• Promotes quality-by-design thinking early in development 

• Supports plain, purposeful writing with participant relevance in mind 

E8 helps ensure the “why” behind every document is as clear as the “what.”

Quick Comparison for Writers 

ICH Guideline	Primary Focus	Where It Applies in Writing
E3	CSR structure and content	Clinical Study Reports (CSRs)
E6 (R2)	Good Clinical Practice (GCP)	Protocols, CSRs, ICFs, IBs
E8 (R1)	General trial design considerations	Protocols, background sections, rationale and design

Final Thoughts 

Understanding the ICH guidelines helps writers align clinical documents with internationally accepted standards. It also supports consistency, transparency, and ethical communication, all of which are key to effective regulatory writing. 

As I continue building experience, I’m finding that familiarity with E3, E6, and E8 provides a solid foundation for contributing confidently to trial documentation at every stage. 

References 

1. ICH E3

International Council for Harmonisation (ICH). E3: Structure and Content of Clinical Study Reports. Step 4 version. July 1996.

2. ICH E6 (R2)

International Council for Harmonisation (ICH). E6(R2): Guideline for Good Clinical Practice. Integrated Addendum to ICH E6(R1). Step 4 version. November 2016.

3. ICH E8 (R1)

International Council for Harmonisation (ICH). E8(R1): General Considerations for Clinical Studies. Step 4 version. October 2021.