Targeted Radiotherapy in Androgen-suppressed Prostate Cancer Patients. (TRAP)

April 22, 2026 updated by: Royal Marsden NHS Foundation Trust

TRAP - Targeted Radiotherapy in Androgen-suppressed Prostate Cancer Patients.

This multi-center, phase II trial will be conducted in men with castration resistant prostate cancer. The aim of the TRAP trial is to test whether a new precise radiotherapy technique called stereotactic body radiotherapy (SBRT) can slow down the growth of metastatic prostate cancer. If SBRT is effective it will represent a new treatment option in these patients, providing more prolonged control without having to resort to chemotherapy and its potentially unpleasant side effects.

In this trial, the investigators will identify men who, despite being on next generation androgen deprivation treatment (Abiraterone or Enzalutamide) have developed one or two new sites of worsening (growing) disease but the rest of their cancer is still responding to hormonal therapy. If it is the case that SBRT can successfully treat the cancer which is resistant to current treatment then the investigators hope they will be able to better control the spread of cancer in these patients for longer.

The investigators also hope that they will be able to use the tell-tale products (gene markers) that are released into the bloodstream in these patients, or identify characteristics on novel imaging such as magnetic resonance imaging (MRI) to help identify patients in the future who will benefit the most.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

For many men with metastatic prostate cancer, the cancer develops resistance to successive systemic therapies and eventually all treatment options are exhausted and the patient succumbs to their disease. It is therefore vital to find ways of evading prostate cancer resistance. Stereotactic body radiotherapy (SBRT) has the advantage that it destroys cancerous tissue irrespective of the underlying genetic deficit within the progressing metastasis. If the resistant clones are localized to 1-2 metastases and can be destroyed or ablated, the patient can continue to receive the benefit of their systemic (androgen deprivation) treatment (Abiraterone or Enzalutamide) which may continue to control the remainder of their disease for many months, possibly even years.

SBRT is a recognised technique for the elimination of isolated metastases in other tumour sites achieving local control of metastasis in 80-90% of cases. This is achieved with very few side effects. In the TRAP trial, the investigators wish to establish whether it is beneficial to target 1 or 2 metastatic sites with SBRT or whether patients will develop polymetastatic progression. Patients enrolled on the trial will receive 30 Gy in 5 fractions on alternate days over 10 days. They will continue their androgen deprivation treatment throughout and following SBRT. Side effects will be closely monitored throughout and patients will be seen at the end of radiotherapy and then 4 weeks after treatment. Thereafter patients will undergo trial follow up three monthly which will includes Prostate Specific Antigen (PSA) monitoring.

In addition to the above procedures, the investigators will use a combination of whole body (WB) diffusion weighted (DW) magnetic resonance imaging (WB DW MRI) and circulating tumour (ct) deoxyribonucleic acid (DNA), 'ct DNA' biomarker analysis with the aim of identifying those patients which benefit most from the combination of SBRT and androgen deprivation treatment. WB DW MRI is a novel MRI technique which shows improved sensitivity compared to standard MRI. The marker ctDNA enables the investigators to explore genomic characterisation and variation of metastases and compare findings with previously explored genome mutations in prostate cancer patients.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
86

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United Kingdom
    • Manchester Greater
      • Manchester, Manchester Greater, United Kingdom, M20 4BX
        • The Christie NHS Foundation Trust
    • Northern Ireland
      • Belfast, Northern Ireland, United Kingdom, BT8 8BH
        • Belfast Health & Social care Trust
    • Surrey
      • Sutton, Surrey, United Kingdom, SM5 3EZ
        • Angelie Tirona
    • Tyne and Wear
      • Newcastle upon Tyne, Tyne and Wear, United Kingdom, NE7 7DN
        • The Newcastle upon Tyne Hospitals NHS Foundation Trust
    • Wales
      • Cardiff, Wales, United Kingdom, CF14 2TL
        • Velindre Cancer Centre
    • West Midlands
      • Birmingham, West Midlands, United Kingdom, B15 2TH
        • University Hospitals Birmingham NHS Foundation Trust
    • West Yorkshire
      • Leeds, West Yorkshire, United Kingdom, LS9 7TF
        • Leeds Teaching Hospitals NHS Trust

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Be willing and able to provide written informed consent for the trial and be ≥18 years of age on day of signing informed consent.
  2. Have metastatic Castration Resistant Prostate Cancer (CRPC) based on biochemical or pathological diagnosis and be on Enzalutamide or Abiraterone.
  3. Have had a minimum of 6 months on Enzalutamide or Abiraterone with evidence of response (PSA, radiological or symptomatic)
  4. Have 1 - 2 metastatic lesions progressing on imaging (CT, bone scan, MRI or other local imaging) or a clinical or imaging diagnosis of progression of a non-irradiated primary site with the remainder of their metastases currently controlled by Enzalutamide or Abiraterone.
  5. Have had no previous radical radiation to the index area (defined as unable to deliver SBRT doses in this protocol without taking normal tissues beyond tolerance).
  6. Have a Performance Status (PS) assessed using the Eastern Co-operative Oncology Group (ECOG) criteria of 0 - 1.
  7. Have an oligoprogressing site, including those that have developed on treatment, in bone, lymph node, prostate or lung but not in liver, brain, adrenal or other sites.
  8. Patients may be symptomatic in the oligoprogressing area. However, there is no urgent need to start radiotherapy.

Exclusion Criteria:

  1. A clinical need exists to switch therapy immediately (e.g. suspicion of rapid clinical progression, urgent need for palliative radiotherapy).
  2. Evidence of previous invasive cancer in the last 5 years, with the exception of non-melanoma skin cancer (non-invasive malignancies such as non-muscle invasive bladder cancer are not excluded).
  3. There is a contra-indication to radiotherapy (e.g. inflammatory bowel disease).
  4. There is a contra-indication to MRI where required for radiotherapy (e.g. cardiac pacemaker, internal defibrillator, shrapnel injury or claustrophobia).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: SBRT + ADT
Enzalutamide OR Abiraterone at licensed doses in combination with stereotactic radiotherapy: 30 Gray in 5 fractions
Radiation: SBRT + ADT
Short course SBRT to 1 or 2 oligo-progressing metastases in addition to continued abiraterone or enzalutamide
Other Names:
  • Enzalutamide or Abiraterone plus stereotactic radiotherapy

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Median Progression-Free Survival (PFS)
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).

Median progression free survival following SBRT to progression, starting new treatment or death from any cause.

Progression is defined as one of the following; (i) PSA progression: PSA rise by at least 25% over post-SBRT baseline (set at 4 weeks), confirmed by a second reading at least 4 weeks later, (ii) Radiological progression: at least 2 new lesions on bone scan or unequivocal progression of soft tissue on CT, or evidence on other local imaging of disease progression (e.g. PET or MRI progression) as per Response Evaluation Criteria In Solid Tumours Criteria (RECIST v1.1) (iii) Symptomatic progression: new or progressing symptoms at the site of a metastasis, or (iv) Date at which the clinician decides to stop Abiraterone/Enzalutamide or starts new line of therapy, whichever occurs sooner.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Progression-Free Survival (PFS) Events
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).

Number of patients that had a PFS event following SBRT in the duration of the study. Progression free survival definition is time from SBRT to progression, starting new treatment or death from any cause.

Progression is defined as one of the following; (i) PSA progression: PSA rise by at least 25% over post-SBRT baseline (set at 4 weeks), confirmed by a second reading at least 4 weeks later, (ii) Radiological progression: at least 2 new lesions on bone scan or unequivocal progression of soft tissue on CT, or evidence on other local imaging of disease progression (e.g. PET or MRI progression) as per Response Evaluation Criteria In Solid Tumours Criteria (RECIST v1.1) (iii) Symptomatic progression: new or progressing symptoms at the site of a metastasis, or (iv) Date at which the clinician decides to stop Abiraterone/Enzalutamide or starts new line of therapy, whichever occurs sooner.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Progression-Free Survival (PFS) Estimates
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).

Progression free survival estimates following SBRT to progression, starting new treatment or death from any cause.

Progression is defined as one of the following; (i) PSA progression: PSA rise by at least 25% over post-SBRT baseline (set at 4 weeks), confirmed by a second reading at least 4 weeks later, (ii) Radiological progression: at least 2 new lesions on bone scan or unequivocal progression of soft tissue on CT, or evidence on other local imaging of disease progression (e.g. PET or MRI progression) as per Response Evaluation Criteria In Solid Tumours Criteria (RECIST v1.1) (iii) Symptomatic progression: new or progressing symptoms at the site of a metastasis, or (iv) Date at which the clinician decides to stop Abiraterone/Enzalutamide or starts new line of therapy, whichever occurs sooner.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Local Control Rate Following SBRT
Time Frame: At the 6 month timepoint from end of SBRT
Overall control defined as stable disease or partial response of irradiated metastases assessed using the RECIST (v 1.1) criteria on imaging such as computed Tomography (CT), magnetic Resonance Imaging (MRI) or Positron Emission Tomography (PET) scan or control on bone scan
At the 6 month timepoint from end of SBRT
Median Overall Survival (OS)
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Median OS following SBRT until death from any cause.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Overall Survival (OS) Events
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Number of patients who had an OS event following SBRT in the duration of the study. Overall survival definition is time from SBRT to death from any cause.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Overall Survival (OS) Estimates
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
OS estimates following SBRT to death from any cause.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Median Time to Administration of Next Line of Therapy or Death
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Median time following SBRT to alternative therapy administration or death.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Administration of Next Line of Therapy or Death Events
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Number of patients that started new treatment or died following SBRT in the duration of the study.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Time to Administration of Next Line of Therapy or Death
Time Frame: Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Time estimates from SBRT to alternative therapy administration or death.
Time on study (up to 24 months from the end of SBRT, with further follow-up after 24 months if patient data were available).
Health Related Quality of Life
Time Frame: Up to 12 months from the end of SBRT
Patient Reported Quality of Life assessed using the EuroQol (EQ) EQ-5D-5L questionnaire. VAS scale is from 0-100. A higher VAS score indicates better quality-of-life. Outcome data has been reported for (i) all completed assessments and for (ii) assessments conducted up to the point of disease progression, in order to exclude the potential influence of progression on quality-of-life outcomes.
Up to 12 months from the end of SBRT
Number of Participants With Incidence and Severity of Treatment Induced Symptoms (RTOG)
Time Frame: Up to 24 months from the end of SBRT
Severity of acute and late side-effects resulting from SBRT assessed using the RTOG (Radiation Therapy Oncology Group) scoring criteria. A higher RTOG grade suggests higher severity of symptoms. Overall maximum grade for each patient at each timepoint is reported.
Up to 24 months from the end of SBRT
Number of Participants With Incidence and Severity of Treatment Induced Symptoms (CTCAE)
Time Frame: Up to 24 months from the end of SBRT
Severity of acute and late side-effects resulting from SBRT assessed using the Common Terminology Criteria for Adverse Events (CTCAE). A higher CTCAE grade suggests higher severity of symptoms. Overall maximum grade for each patient at each timepoint is reported.
Up to 24 months from the end of SBRT
Prostate Specific Antigen (PSA) Values
Time Frame: Up to 12 months from the end of SBRT
Prostate Specific Antigen (PSA) values recorded post-SBRT
Up to 12 months from the end of SBRT

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Exploration of novel bio-markers to assess response to SBRT treatment
Time Frame: Assessment of Progression Free Survival at 6 months and 1 year
Levels of circulating tumor Deoxyribonucleic Acid (ctDNA)
Assessment of Progression Free Survival at 6 months and 1 year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Royal Marsden NHS Foundation Trust

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University College, London
The Leeds Teaching Hospitals NHS Trust
Belfast Health and Social Care Trust
University Hospital Birmingham NHS Foundation Trust
Newcastle-upon-Tyne Hospitals NHS Trust
The Christie NHS Foundation Trust
Velindre NHS Trust
Prostate Cancer UK

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Alison Tree, FRCR, Royal Marsden NHS Foundation Trust

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 13, 2018

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 31, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 31, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 15, 2018

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 21, 2018

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 23, 2018

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 14, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 22, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CCR 4781

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Human tissue (blood) in surplus will be made available for other ethically approved research provided patients have given their informed consent

IPD Sharing Time Frame

Not anticipated to be before 6 months have elapsed following recruitment of the last patient.

IPD Sharing Access Criteria

On provision of written request

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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