The UK has paused a clinical trial on puberty blockers for children after the medicines regulator raised new safety concerns. The agency warned about uncertain long-term biological risks and called for a minimum age of 14.
The Medicines and Healthcare products Regulatory Agency will meet King’s College London next week. They will review the study design and address wellbeing issues. The Department of Health and Social Care confirmed that recruitment will not begin yet.
The Pathways trial followed a recommendation from the Cass review. That review found weak evidence for benefits in young people with gender dysphoria. Dr Hilary Cass said a controlled trial offered the only clear way to understand the treatment.
The government said child safety remains the main condition for approval. Experts will examine the evidence before any trial starts.
King’s College London said the project places young people’s health first. Researchers will work with the regulator during the scientific review. They aim to build reliable evidence for future clinical decisions.
The original plan allowed participants as young as ten. The regulator now wants a stepwise approach that begins at age 14 because of unknown long-term effects.
NHS England already limits puberty blockers to research settings. Professor Sir Jonathan Montgomery said the pause strengthens the protocol and protects participants.
