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Combined review is the way research teams seek approval for new Clinical Trials of Investigational Medicinal Products (CTIMPs) and combined medicine and device trials.

Research teams make a single application using a new part of IRAS, which goes to both the Medicines and Healthcare products Regulatory Agency (MHRA) and a research ethics committee (REC) at the same time. The application also goes for study wide review, such as HRA and HCRW approval, if the study is to take place in the NHS or Northern Ireland HSC.

The regulatory and ethics reviews are done in parallel and any requests for further information (RFIs) are raised jointly. A single response to these requests leads to a single decision from both reviews. Study wide review is usually issued at the same time as MHRA and REC, but may come later if there are still issues to discuss with the applicant.

IRAS is used for the initial application and supports the trial through amendments right up to the end of the trial. Research teams can allocate different roles in the system for colleagues working on the project.

Initial review process and timelines

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Long description

If there are questions during the review, a ‘Request for Further Information’ (RFI) may be raised and applicants will need to provide additional information or clarifications. Applicants can request an extension if more than 14 days is needed to respond to the RFI, by emailing the MHRA at If more than 14 days is needed, this will affect the 60-day timeline.

For help with tasks in new IRAS, please contact the Service Desk at

Quick Start Guide

Getting started

Further guidance and support

Featured video

We've produced a short explainer video for newcomers to combined review. Check it out below.

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