The UK has paused a clinical trial on puberty blockers for children after a warning from the medicines regulator. The agency cited unknown long-term biological risks and called for a minimum age of 14.
The Medicines and Healthcare products Regulatory Agency will hold talks with King’s College London next week. The Department of Health and Social Care said the study will not recruit participants until they resolve the concerns.
The Pathways trial followed a recommendation from the Cass review. That review found weak evidence for the benefits of puberty blockers in young people. Dr Hilary Cass said only a clinical trial could clarify their effects.
The government said child safety remains the main condition for approval. Clinicians are now examining the new evidence. The trial will proceed only if experts confirm it is safe and necessary.
King’s College London said young people’s wellbeing guides the project. The team will work with the regulator during the scientific review. The researchers aim to build a stronger evidence base for future decisions.
The study had planned to recruit 226 participants over three years. It originally allowed children as young as ten. The regulator now wants a stepwise approach that starts at 14 because of uncertain risks.
NHS England has already ended routine use of puberty blockers for gender dysphoria. Their use now remains limited to research.
Health law expert Sir Jonathan Montgomery said the pause will improve the protocol. He stressed that the process focuses on participant safety and shows proper regulation at work.
