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MHRA – Clinical Trial Authorisation

The MHRA Clinical Trials Unit assesses applications from sponsors to conduct clinical trials of medicinal products.

Certain trials may require expert advice from a specialist committee. Details of the types of trials and the process for seeking expert input are set out on the MHRA website. 

For EU multi-national clinical trials there is a Voluntary Harmonisation Procedure which allows sponsors to obtain a harmonised assessment of their Clinical Trial Authorisation (CTA) application by all the National Competent Authorities involved, avoiding the need for multiple applications in each country.  



The application will be validated on receipt and an acknowledgement letter will be sent to the person submitting the application.

  • If the application is valid then the assessment period will begin from the date of receipt of a valid application.
  • If the application is not valid then the person making the application will be told of the deficiencies. A full new application containing all the necessary components should be provided. Invalid submissions will be confidentially destroyed.

For more information about the validation process and common errors in applications please refer to the MHRA website. 



Frequent causes of non-acceptance relate to the following issues:

  • safety monitoring
  • contraception/lactating women/women of childbearing potential
  • follow up provisions missing/insufficient
  • dose level or duration
  • manufacture and control of placebo product 
  • information on modifications to licensed products (eg encapsulation).

It is only possible to submit updated or additional information to MHRA before the assessment process has begun. Please refer to the MHRA website for details.

When the application has been assessed the applicant will be sent a letter informing them of:

  • acceptance of the request for a clinical trial authorisation or
  • acceptance of the request for a clinical trial authorisation subject to conditions or
  • grounds for non-acceptance of the request for a clinical trial authorisation.

For more information about what these decisions mean and the next steps in each case, please refer to the MHRA website. 

It is possible that the outcome of the assessment is acceptance of the request with conditions applied. It is not necessary to confirm to MHRA that the conditions are met. However, it may be appropriate to provide any relevant clarifications to other review bodies to avoid confusion. Where the conditions are not met, the authorisation is not valid and the sponsor should submit a substantial amendment supported by the relevant documentation to make the necessary changes.

Please note that where other review bodies request changes during their review process, these do not meet the definition of substantial or non-substantial amendments for those bodies, they are termed ‘revisions’, and are not handled as amendments. However, if these revisions meet the criteria for substantial amendments that require notification to MHRA, they must be submitted to MHRA in accordance with the amendments process.

If the MHRA issues grounds for non-acceptance an application addressing all the requested issues must be made within the specified number of days.


When will I get approval?

The initial assessment will be performed within 30 days. Applications for Healthy Volunteer Trials and sponsor-determined Phase I trials in non-oncology patients, will be assessed and processed within 30 days, with an average of 14 days or less.

If an amended application is required following non-acceptance, the decision will be sent within 60 days of receiving the original valid application. Responses for phase 1 healthy volunteer studies will be assessed within an average of 14 days. Notification of the MHRA’s decision relating to an amended request for a gene therapy, somatic cell therapy (including xenogenic cell therapy) product or products containing genetically modified organisms will be sent within 90 days of receiving the original application unless otherwise advised.

Where the MHRA does not accept a request for clinical trial authorisation, the refusal is not notified to the applicant. For general medicinal products or products with special characteristics, the refusal will occur 60 days from the date of receipt of the original valid application. For gene therapy, somatic cell therapy (including xenogenic cell therapy), tissue engineered products or products containing genetically modified organisms, the refusal will occur 90 days after the MHRA received the original valid application, unless otherwise advised.

Applications through the notification scheme for ‘Type A’ trials will be acknowledged by the MHRA with a letter to say that the trial may go ahead after 14 days from receipt of notification, if the MHRA has not raised any objections. This means that the acknowledgement letter will act as the authorisation. If the MHRA raises objections to the notification, then the submission will be assessed as for a standard request for authorisation.

Trials of certain products may also require other approvals. For details see: