Within the scope of the Clinical Trial Regulations?
Within the scope of the Clinical Trial Regulations?

There are a number of steps to follow before a trial can commence. The first step is to confirm whether it falls within the scope of the European Directive (2001/20/EC) (PDF, 152 KB)Link open in a new window. This Directive was transposed into UK law by means of The Medicines for Human Use (Clinical Trials) Regulations 2004Link open in a new window, which together with its amendments are referred to as the Clinical Trials Regulations within this Toolkit.

The Clinical Trials Regulations cover only investigations/studies which are undertaken to ascertain the efficacy or safety of a medicine in human subjects. Non-interventional trials are excluded from the Regulations. To classify a trial as non-interventional, it must meet all of the following criteria:

  • involves products with a marketing authorisation that are prescribed in the usual manner and used in accordance with the authorisation;
  • when the patient is assigned to a therapeutic strategy within current practice and not according to a protocol;
  • the diagnostic or monitoring procedures are only those ordinarily applied to the therapeutic strategy;
  • and epidemiological methods are used to analyse the data.

(defined in full in column E of the MHRA algorithm linked below).

If a study is not for the purpose of ascertaining the effects of or reactions to a product and the product is simply being used as an aid or tool in the study, it is not a clinical trial covered by the Regulations. For example, in the case of the study of blood flow involving the infusion of vasoactive substances, if the purpose of the study is to monitor the effects of a particular substance to see if it is effective in achieving a particular physiological effect, then it is not a clinical trial. If the infusion is for the purpose of modifying the rate of flow for a therapeutic indication such as claudication, it would be deemed a trial under the Directive as the purpose of the study is to establish the efficacy of a particular medicine.

A Clinical Trials Regulations Flowchart (pdf, 76.83 KB)Link open in a new window has been developed which describes the relationship between the EU Directive and UK regulation including a brief description of each regulation. Any trial that falls within the scope of Directive 2001/20/EC is known as a Clinical Trial of an Investigational Medicinal Product (CTIMP).

The Medicines and Healthcare Regulatory Agency (MHRA) is the competent authority that regulates CTIMPs in the UK. The MHRA web pagesLink open in a new window describe the difference between Investigational Medicinal Products (IMPs) and Non-Investigational Products (NIMPs) and contains an algorithm (PDF)Link open in a new window designed to help researchers determine if their trial is a CTIMP.

Researchers planning a CTIMP should be familiar with the MHRA Clinical Trials PagesLink open in a new window to help ensure all legal requirements are considered.


We would welcome your feedback and suggestions on how we can improve the toolkit. Please help to keep the toolkit up-to-date by reporting any out-of-date content or broken links.

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Key to Symbols

  • Demonstrates processes that can be done in parallel
  • Demonstrates that not all processes will apply to all trials
Standard Process Legal Requirement Good Practice
Specific for trials within Directive's scope
Relevant to all trials