Background
The claimants challenged regulatory decisions made in November 2025 and June 2026 approving the PATHWAYS Trial, a clinical trial of gonadotropin-releasing hormone analogues, also known as puberty-suppressing hormones, for children and young people with persistent gender incongruence. NHS England commissioned the trial in response to the Cass Review’s finding that the evidence base for this treatment was very weak. King’s College London and South London and Maudsley NHS Foundation Trust co-sponsored the trial.
The trial was designed to assess the short- and medium-term benefits and risks of puberty suppression. Prospective participants would undergo extended assessment by specialist gender services, individual clinical evaluation, review by a national multidisciplinary team, and an assent-and-parental-consent process. The Medicines and Healthcare Products Regulatory Agency assessed trial safety and participant safeguards, while a Health Research Authority research ethics committee considered ethical approval. Both approved the trial in November 2025 and affirmed approval of a modified protocol in June 2026.
The claimants sought permission to apply for judicial review on five grounds, including alleged failures concerning access to treatment after trial participation, handling of third-party comments, transparency, the trial’s scientific rationale, and reasons for approval. They also sought interim relief preventing the trial from proceeding. Its preparatory stages were scheduled to begin on 1 August 2026, although administration of hormones was not expected before November.
The Court’s Holding
Mr Justice Chamberlain refused permission to apply for judicial review because none of the five grounds had a realistic prospect of success. The court stressed that its role was not to decide whether it agreed with the regulators’ scientific judgments, but to determine whether they had acted contrary to the statutory scheme or otherwise unlawfully. Specialist regulators’ technical and scientific assessments warrant particular judicial caution when challenged on rationality grounds.
The MHRA rationally addressed whether participants could obtain puberty-suppressing or masculinising and feminising hormones after leaving the trial and rationally concluded that the statutory requirement of some direct benefit for the participant group was met. The HRA was not legally required to give the research ethics committee every third-party comment, and its decisions about which comments to provide were rational. The remaining transparency complaint did not justify permission, while the claim that the pragmatic trial lacked a valid testable hypothesis misunderstood its purpose of assessing benefit, harm, or no material difference across specified domains.
The regulatory scheme did not require public reasons when a clinical trial or protocol modification was approved, and the court found no sufficiently strong policy basis for imposing such a common-law duty. Because permission was refused, interim relief did not arise. The judge nevertheless held that, even had an arguable ground been established, the public and participant harms from delaying the trial would have outweighed the potential harms from allowing it to begin while litigation continued.
Key Takeaways
- Courts will exercise substantial caution before overturning technical or scientific judgments entrusted by legislation to specialist clinical-trial regulators.
- The MHRA and HRA lawfully and rationally approved the PATHWAYS Trial and its modified protocol after considering participant safeguards, potential benefit, and post-trial treatment issues.
- Permission for judicial review and interim relief were refused, allowing the trial’s scheduled preparatory work to proceed.
Why It Matters
The decision permits the PATHWAYS Trial to proceed toward addressing the evidence gap identified by the Cass Review concerning puberty-suppressing treatment for children and young people with gender incongruence. It does not decide whether that treatment is clinically effective or appropriate as a matter of policy; it holds that the specialist regulators’ approvals were not arguably unlawful.
The judgment also illustrates the demanding threshold for rationality challenges to expert regulators and the weight given, at the interim-relief stage, to public-health research, participants’ interests, and the public interest in allowing presumptively valid regulatory decisions to take effect.