Developing guidance for surrogate outcomes in clinical trials

SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) and CONSORT (Consolidated Standards Of Reporting Trials) are evidence-based guidelines created to improve and standardise how researchers design and conduct clinical trials. They consist of checklists and explanatory documents to help researchers while they are setting up or reporting on a trial.

SPIRIT focuses on publishing the clinical trial protocol before the trial is conducted, while CONSORT focuses on reporting the results of clinical trials. Trial protocols specify the methods researchers will be using during a trial, such as the real target outcomes they might be expecting. Anyone reporting the results of a trial, or publishing its protocol, can refer to the relevant guidelines to make sure their trial protocols and reports are clear, complete and transparent.

In clinical trials, a real target outcome is an event or outcome that lets researchers determine if a treatment or drug has been successful. To understand whether an intervention has been successful researchers can also look at surrogate outcomes. Surrogate outcomes are substitutes for real target outcomes.

For example, blood pressure is a surrogate outcome for several target outcomes such as life expectancy, stroke and heart attacks. Measuring the size of a tumour could be used as a surrogate outcome for how long a patient is likely to survive.

Researchers use surrogate outcomes because they can be measured more quickly and easily than the real target outcome. Doing this may allow new drugs to be approved more quickly to treat serious or life-threatening diseases, such as cancer. However, surrogate outcomes aren’t always a true reflection of how well a treatment works.

Project aims

This project was aimed at developing and disseminating updated SPIRIT and CONSORT guidelines to help researchers measure and report surrogate outcomes in trials.

The work was led by:

• Rod Taylor, Professor Population Health Research (MRC/CSO Social & Public Health Sciences Unit) at the University of Glasgow
• Ms Oriana Ciani, Associate Professor of Health Economics, Bocconi University

Jane Blazeby, Professor of Surgery at the Bristol Medical School, represented Bristol’s BRC during this collaboration.

What we did

We collaborated with the project leads on developing both SPIRIT and CONSORT guidelines.

Together with the team Anni King, Senior Research Associate at the Centre for Surgical Research, Bristol Medical School, created an animation to help the public and patients understand our findings.

Watch the video to find out more about surrogate outcomes

To review the reporting checklists and accompanying documentation developed by the project team, please refer to the two papers listed below.