Trial on Puberty-Blocking Drugs Paused Over Safety Issues
A clinical trial evaluating the risks and benefits of puberty-blocking drugs for children questioning their gender identity has been paused following safety concerns raised by the UK medicines regulator.
The Medicines and Healthcare Products Regulatory Agency (MHRA) is scheduled to hold discussions with King's College London, whose researchers are leading the trial, next week to address these concerns, according to a government statement.
Trial Details and Participant Criteria
The trial, announced in November after receiving approval from both the MHRA and the Health Research Authority, was planned to involve over 220 children aged approximately 11 to 15 years. An MHRA spokesperson emphasized that the "safety and wellbeing" of participants, who have not yet been recruited, remains "paramount."
Puberty blockers, also known as puberty suppressing hormones (PSH), are used to delay or prevent the onset of puberty. However, their use for individuals under 18 questioning their gender identity was banned in 2024.
The clinical trial, named Pathways, was designed to include children experiencing distress related to their gender identity who are currently accessing gender services. It aimed to study the effects of puberty blockers on their physical, social, and emotional wellbeing.
MHRA's Concerns and Recommendations
The MHRA has proposed raising the minimum age for trial participants to 14 years. It also recommended enhanced monitoring of bone density and a more rigorous consent process for those involved.
In a letter published on the government website on Friday, the MHRA expressed concerns regarding the current age threshold for participants:
"Since potentially significant and, as yet, unquantified risk of long-term biological harms is present to participants and biological safety has not been definitively demonstrated in this proposed cohort, at the very least, there should be a graded/stepwise approach starting with those aged 14 as the lower limit of eligibility,"
In a separate statement released on Friday evening, an MHRA spokesperson noted that it is "part of the usual process that clinical trials are kept continuously under review and for us to have active scientific dialogue with the trial sponsors." They added,
"We have raised some concerns related to the wellbeing of participants and scientific dialogue will now follow with the trial sponsor,"
Government Response and Trial Status
The Department of Health & Social Care (DHSC) confirmed that recruitment of participants will not proceed until the MHRA's concerns have been resolved in discussions with the trial clinicians.
A DHSC spokesperson stated,
"We have always been clear about the red lines regarding this trial – ensuring the safety and wellbeing of the children and young people involved and always being led by the clinical evidence,"
They further emphasized that the trial would "only be allowed to go ahead if the expert scientific and clinical evidence and advice conclude it is both safe and necessary."
King's College London's Position
A spokesperson for King's College London highlighted that the wellbeing and health of young people experiencing gender incongruence and their families is its "priority." They also stressed that "rigour and ongoing scientific discussion" are vital for a clinical trial, especially one as complex as Pathways.
Opposition and Legal Challenges
Some medical professionals have questioned the necessity of the trial. Additionally, campaigners are pursuing legal action against the MHRA, the government, and other parties involved, arguing that the trial is unethical and that children cannot provide fully informed consent for a treatment that may impact their future fertility.
Background on Gender Medicine and Previous Reviews
A 2024 review conducted by Dr Hilary Cass concluded that gender medicine had been operating on "shaky foundations" regarding evidence supporting treatments. The ban on puberty blockers for individuals under 18 was introduced following concerns about their safety raised in this review.
Despite this, Dr Cass told the BBC last week that it was "vital" for the trial involving puberty blockers for under-16s to proceed, warning,
"we're going to have ongoing charlatans just handing out inappropriate drugs,"
citing the private sale of these drugs, particularly online.
