MHRA issues new guidance on its approach to clinical trial applications that rely on non-clinical safety data generated outside the OECD Mutual Acceptance of Data system.
The MHRA has today, 4th November 2026, published guidance explaining its patient-centred approach to clinical trial applications that rely on non-clinical safety data generated outside the Organisation for Economic Co-operation and Development (OECD) Mutual Acceptance of Data framework.
The approach will help support a further risk-proportionate approach to clinical research, helping advance the development of new treatments and increase opportunities for UK patients to take part in trials.
The OECD Mutual Acceptance of Data system provides an internationally recognised approach for generating non-clinical safety data, in line with agreed standards for testing and Good Laboratory Practice. Data generated within the framework remain the expected basis for UK clinical trial applications.
The new guidance explains how the MHRA may consider non-clinical data generated outside the OECD framework in individual clinical trial applications where the available evidence and circumstances of the intended patient population support further regulatory consideration. It provides greater clarity for developers while maintaining standards for participant safety, scientific rigour and data integrity.
Under this approach, the MHRA will consider the available non-clinical evidence alongside the circumstances of the proposed trial. This includes the participant population, the seriousness of the condition, unmet medical need and the stage and design of the trial.
Accordingly, in limited circumstances, the MHRA may consider an enhanced non-clinical assessment, including for first-in-human trials in patients with advanced cancers or other serious or life-threatening conditions where there is significant unmet medical need. This provides additional scientific scrutiny of the available evidence where appropriate.
Alongside the assessment of individual applications, the MHRA will undertake a strategic, risk-based programme of inspections of non-clinical test facilities that are frequently identified in clinical trial applications submitted to the UK. This will help inform future regulatory assessments and support a proportionate, evidence-based approach to regulatory oversight.
The guidance does not change the standards expected for the quality, safety or integrity of pivotal non-clinical safety data. It provides greater clarity on how the MHRA will assess available evidence and apply proportionate regulatory scrutiny to individual applications.
The MHRA’s approach will evolve in line with regulatory experience, compliance intelligence and outcomes from test facility inspections.
Developers planning to use non-clinical data generated outside the OECD Mutual Acceptance of Data system are encouraged to engage early before submitting a clinical trial application.
For more information, read Use of non-OECD MAD non-clinical data in support of UK clinical trial authorisation applications - GOV.UK