The British regulatory agency MHRA (Medicines and Healthcare products Regulatory Agency) has issued new guidance clarifying its approach to evaluating applications for clinical trials in cases where non-clinical safety data for medicinal products have been obtained outside the Mutual Acceptance of Data system of the Organisation for Economic Co-operation and Development (OECD Mutual Acceptance of Data, MAD). The OECD MAD system is designed to ensure international recognition of non-clinical safety research results conducted in accordance with Good Laboratory Practice (GLP) principles of participating countries. This prevents duplication of studies and accelerates the process of drug registration at the international level. The new MHRA guidance establishes criteria and procedures that the agency will follow when reviewing applications containing data obtained outside this system. This is relevant for pharmaceutical developers who conduct non-clinical research in laboratories that are not part of the OECD mutual recognition system or in countries that are not parties to this agreement. The document is aimed at increasing transparency in the regulatory process and giving developers a clearer understanding of what quality and reliability requirements are imposed on such data for their acceptability when submitting applications for clinical trials in the United Kingdom. It is expected that this will simplify the research planning process for pharmaceutical companies working with international partners and laboratories. The initiative is viewed as part of MHRA's ongoing work to adapt the UK's regulatory framework following the country's exit from the European Union, as well as to strengthen cooperation with global partners in the field of medicinal product regulation.