Trial protocol evaluates 9-month ADT plus ARTA for high-risk prostate cancer non-inferiorityNew trial tests shorter hormone therapy for high-risk prostate cancer

Clinical oncology (Royal College of Radiologists (Great Britain)) Published September 10, 2026 Study authors: Murthy V, Maitre P, Priya S, Dhingra S, Dhanawat A, Shah M, Bhattacharya K, Adepu A, Singh P, Phurai… PubMed ↗ NCT06818682 ↗ DOI ↗ Editorial oversight: Dr. Julia Lee, PhD · Oncology, Genomics & Drug Development

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Key Takeaway

Note that this is a trial protocol; no clinical outcomes or safety data are currently available.

This Phase II multicentre trial protocol evaluates a shortened, intensified androgen suppression strategy for 206 patients with high-risk prostate cancer (HRPCa) staged with PSMA imaging. The primary objective is to determine if a shorter regimen is non-inferior to standard care.

The intervention group receives 9 months of ADT and 6 months of an androgen receptor-targeted agent (ARTA) combined with definitive dose-escalated hypofractionated pelvic radiotherapy. The comparator group receives 24-month ADT with the same radiotherapy regimen. The primary outcome is 5-year disease-free survival (DFS).

As of February 2025, nearly a third of enrollment was completed. No clinical results, safety data, or tolerability metrics are reported. The study is currently in the early enrollment phase, and results are not yet available.

This trial aims to determine if a shorter, intensified androgen suppression strategy is non-inferior to the standard 24-month ADT for high-risk prostate cancer. Because this is a trial protocol, no clinical outcomes are reported yet, and the non-inferiority margin is a planned parameter rather than a result.

How this fits prior evidence

How this fits prior evidence: This trial addresses a gap in treatment duration for high-risk prostate cancer. It builds upon the finding that 80 Gy radiotherapy with long-term ADT significantly improves 10-year progression-free survival in high-risk prostate cancer. While the prior finding supports long-term ADT, this protocol investigates if a shorter, intensified regimen involving an ARTA can achieve non-inferiority to the standard 24-month ADT period.

Living with high-risk prostate cancer means facing intensive treatments that can last a long time. Doctors are currently looking for ways to make these treatments more efficient without sacrificing the effectiveness of the care. This new study aims to see if a shorter, more intense hormone suppression strategy can match the results of the standard 24-month treatment plan.

The trial involves 206 patients with high-risk prostate cancer. One group will receive 9 months of androgen deprivation therapy followed by 6 months of a targeted agent. The other group will receive the standard 24 months of androgen deprivation therapy. Both groups will also receive pelvic radiotherapy.

Because this is a trial protocol, the study is still in its early stages. As of February 2025, about one-third of the participants have been enrolled. Since the study is still beginning, there are no results yet regarding survival rates or side effects. It is an early step in finding out if a shorter treatment path is a viable option for patients.

What this means for you:

A new trial is testing if a shorter, more intense hormone therapy is as effective as the standard 24-month plan.

Common questions

What is the goal of this new study?

The goal is to see if a shorter, more intense hormone suppression strategy is non-inferior to the standard 24-month androgen deprivation therapy for patients with high-risk prostate cancer. This helps doctors determine if patients can achieve similar results with a shorter treatment timeline.

How many people are participating in the trial?

The study is designed to include 206 patients with high-risk prostate cancer who have been identified using specific imaging. As of February 2025, nearly a third of the enrollment has been completed.

Are there any results available yet?

Because this is a trial protocol, the study is currently in the early enrollment phase. No clinical outcomes, such as survival rates or side effects, are available yet. You should speak with your doctor about current treatment options.

Study Details

Study typeRct

Sample sizen = 206

EvidenceLevel 2

Follow-up9.0 mo

PublishedSep 2026

PMID42567090

TrialNCT06818682

View Original Abstract ↓

AIM: To assess the efficacy of a short, intensified regimen of androgen deprivation therapy (ADT) and androgen receptor-targeted agent (ARTA) with curative-intent external beam radiotherapy (XRT) for high-risk prostate cancer (HRPCa) staged with prostate specific membrane antigen (PSMA) imaging. MATERIALS AND METHODS: The RELAX (Reduced Length of ADT and ARTA with XRT in high-risk prostate cancer) trial is a multicentre, phase II randomised non-inferiority trial comparing 9 months of ADT and 6 months of ARTA against the standard 24-month ADT, with definitive dose-escalated hypofractionated pelvic radiotherapy for PSMA-staged non-metastatic HRPCa. The primary endpoint is 5-year disease-free survival (DFS), defined from randomisation to first biochemical or clinico-radiological recurrence or any-cause death. Secondary endpoints include biochemical failure-free survival, metastasis-free survival, overall survival, testosterone recovery, treatment-related adverse effects, and patient-reported outcomes. Participants are monitored with serial serum PSA and testosterone levels, CTCAE and PRO-CTCAE assessments, and PSMA-PETCT at recurrence. The non-inferiority margin is set at 10% absolute difference from an expected 5-year DFS of 85% in the standard arm, with intention-to-treat analysis. The trial is ethics board approved and funded by institutional intramural grant, and registered on clinicaltrials.gov (NCT06818682). RESULTS: The planned accrual of 206 participants commenced in February 2025, with nearly a third of enrolment completed till date. CONCLUSION: The RELAX trial incorporates contemporary standards of PSMA-based staging, dose-escalated hypofractionated radiotherapy, and ARTA for HRPCa. The results are expected to inform the efficacy of a shorter, intensified androgen suppression strategy against the prevailing standard of long-term ADT for these patients.

Trial protocol evaluates 9-month ADT plus ARTA for high-risk prostate cancer non-inferiorityNew trial tests shorter hormone therapy for high-risk prostate cancer

How this fits prior evidence

Common questions

Study Details

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Trial protocol evaluates 9-month ADT plus ARTA for high-risk prostate cancer non-inferiorityNew trial tests shorter hormone therapy for high-risk prostate cancer

How this fits prior evidence

Common questions

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