High Court refuses challenge to PATHWAYS puberty blockers clinical trial

Today, Friday 31 July, Mr Justice Chamberlain refused permission in the High Court for a judicial review challenging the regulatory approvals granted to the PATHWAYS clinical trial and also refused an application for interim relief seeking to prevent the trial from proceeding.

The PATHWAYS trial was commissioned to address the evidence gap identified by the Cass Review concerning the use of puberty suppressing hormones in children and young people experiencing gender incongruence. The study is co-sponsored by King's College London and South London and Maudsley NHS Foundation Trust.

Following a two day hearing on 27 and 28 July 2026, the Court concluded that none of the claimants' grounds of challenge had a realistic prospect of success. In reaching that decision, the Court emphasised that the trial had been designed with "conspicuous care", that it had undergone rigorous scrutiny by the relevant specialist regulators, and that the courts should exercise caution before interfering with decisions involving scientific and technical expertise.

The judgment found that both the Medicines and Healthcare products Regulatory Agency (MHRA) and the Health Research Authority (HRA) had acted lawfully and rationally in approving the trial and subsequent protocol modifications. The Court also held that the public interest and the interests of trial participants strongly favoured allowing the study to continue.

The proceedings attracted significant national media attention, including coverage by the BBC, The Times and The Guardian.

Fiona Scolding KC appeared for South London and Maudsley NHS Foundation Trust, one of the trial's co-sponsors and an interested party in the proceedings, instructed by Stuart Marchant of Bevan Brittan.