ICH E6 is an internationally recognised Good Clinical Practice standard for the ethical, scientific and quality conduct of clinical trials involving human participants. In the two decades since ICH E6 was first published, clinical trials have become more complex with respect to trial design, use of technology, quantity of data collected and involvement of central testing facilities or other service providers. The latest revision, ICH E6(R3), addresses the complexities of clinical trials in the current global regulatory climate and builds on key concepts outlined in ICH E8(R1): General Considerations for Clinical Studies.

The ICH E6(R3) guideline on Good Clinical Practice (GCP), comprising the Principles, Annex 1 and Annex 2, was adopted in two stages. The Principles and Annex 1 were adopted on 6 January 2025, introducing a flexible, risk-based framework for interventional clinical trials that accommodates a modern approach to the design and conduct of clinical trials. Annex 2 was subsequently adopted on 3 June 2026, providing additional GCP considerations tailored to the evolving clinical trial landscape, covering decentralised elements, pragmatic elements and the use of real-world data. Because Annex 2 builds upon the foundations established in the Principles and Annex 1 and is not intended to be read in isolation, all three have been consolidated into a single unified ICH E6(R3) guideline.

Note: As implementation of the Principles and Annex 1 was already underway before the adoption of Annex 2, ICH will temporarily make Annex 2 available as a standalone document to help stakeholders easily locate and apply the new content. This standalone version will be available through the end of 2026 only.