The UK Medicines and Healthcare products Regulatory Agency (MHRA) has opened a consultation on changes to the definition of gene therapy medicinal products, updating terminology that was developed before current synthetic nucleic acid and genome-editing technologies had matured.
The consultation, published on 11 May 2026, concerns the definition used in the Human Medicines Regulations 2012. Comments are due by 22 June 2026. The proposals would then require changes to the regulations.
MHRA’s starting point is that the existing definition was developed in 2007 and depends heavily on biological origin, recombinant nucleic acids and a direct link between the transferred sequence and the therapeutic, prophylactic or diagnostic effect. The agency says this no longer fits all products now entering development, including synthetic genetic material, novel genome-editing systems and highly engineered cells and tissues.
The proposed definition would remove the requirement for a gene therapy medicinal product to be biological in origin. It would bring synthetic nucleic acids within scope where they are transcribed or translated, and it would classify products as gene therapies where their mechanism involves deliberate, sequence-specific genome editing. MHRA also proposes to remove the requirement that the transferred genetic material must itself be directly responsible for the product’s therapeutic effect.
The consultation keeps the existing exclusion for vaccines against infectious diseases. MHRA also seeks views on how far the UK definition should mirror proposed changes to the EU definition, including whether the UK should use a duration-based test such as ‘long-lasting’ transcription or translation.
The access implications are indirect but practical. For advanced medicines, regulatory classification shapes the development route, applicable evidence standards and the scope for a risk-based approach. Clearer classification should reduce uncertainty for products at the boundary between gene therapy, synthetic nucleic acid medicines and engineered cell therapies. Early clarity on whether a product falls within the gene therapy category can shape evidence-generation plans, long-term follow-up requirements and the later access dossier.'
Source: Medicines and Healthcare products Regulatory Agency
Link: Consultation on the regulation of Gene therapy medicinal products
Date: 11 May 2026
