MHRA issues guidance on evaluating non-OECD clinical trial safety data

What was announced

The Medicines and Healthcare products Regulatory Agency, known as the MHRA, issued guidance on how it assesses non-clinical safety data collected outside the Organisation for Economic Co-operation and Development (OECD) Mutual Acceptance of Data system. Non-clinical data comes from laboratory tests and animal studies conducted before a medicine is given to humans.

The OECD framework sets shared standards for Good Laboratory Practice. Data from member countries remains the standard baseline for UK trial applications. Under the new guidance, the MHRA may review non-clinical evidence from outside this system on a case-by-case basis. This option applies when supported by the patient population, the severity of the condition, unmet medical needs, and trial design. For example, the agency may perform an enhanced assessment for first-in-human trials treating advanced cancers or life-threatening illnesses. The regulator also announced a strategic program to inspect non-clinical test facilities outside the OECD framework that appear frequently in UK applications.

What it means

Medical trial sponsors often run initial safety tests across different global facilities. Previously, using safety data from non-OECD testing sites created regulatory uncertainty in the UK.

By clarifying its review criteria, the MHRA gives drug developers a clear pathway to submit applications without discarding non-OECD lab findings. This flexibility can help speed up the approval process for clinical trials in the UK, particularly for severe illnesses with limited existing therapies. Drug developers planning to use non-OECD data should contact the regulator early before submitting an application. The MHRA stated that expected standards for safety, trial data integrity, and quality remain the same.

What the announcement does not tell us

The announcement leaves several practical details unresolved. It does not list which specific non-OECD countries or laboratories the MHRA frequently sees in clinical trial filings.

The document also does not state how long an enhanced non-clinical assessment will take compared to standard reviews, or whether applicants must pay additional fees for facility inspections. Finally, the text does not outline the exact criteria inspectors will use during site visits, nor does it specify when the inspection program will begin.