Clinical Trial Decision Tool

The CTR Classification Guide is an interactive European web‑based clinical trial decision tool that translates the definitions in the EU Clinical Trials Regulation (CTR 536/2014) into a practical set of questions. Developed by Paul Janssen Futurelab Leiden at Leiden University Medical Center in collaboration with the Dutch Central Committee on Research Involving Human Subjects (CCMO), it supports investigators who need to understand whether their planned research with medicinal products is regulated as a clinical trial in the EU/EEA.

Key concepts covered include:

• Scope of the CTR for clinical trials with medicinal products conducted in EU and EEA countries.
• Distinction between clinical trials and studies outside CTR scope, based on whether medicinal products are investigated and whether participants undergo additional procedures or rules of behaviour beyond normal clinical practice.
• Criteria for low‑intervention clinical trials, including use of authorised medicinal products and minimal additional risk and burden compared with standard care.
• Consequences of classification for regulatory requirements, such as adapted provisions for low‑intervention trials.
  Investigators are guided step by step to indicate whether their project involves medicinal products, how these are used and what additional procedures participants undergo. 

Based on these answers, the tool indicates whether the study is:

• A clinical trial of medicinal products under the CTR.
• A low‑intervention clinical trial.
• Outside the scope of the CTR, with other legal frameworks potentially applying.

For investigator‑initiated clinical studies, the CTR Classification Guide can be used:

• At concept and feasibility stage to check whether CTR submission through the Clinical Trials Information System (CTIS) will be required.
• During protocol development to document the reasoning behind classification decisions and align study design with the applicable regulatory framework.
• When updating or transitioning ongoing projects to ensure compliance with CTR implementation timelines in the EU/EEA.

It is intended for investigators, sponsors, research support offices and ethics committees working with clinical research on medicinal products in Europe.