HIghly MetAstatic Life Prolonging Therapy-Resistant Prostate Cancer: Role of Stereotactic Radiotherapy for Bone and Lymph Node Metastases (HIMARS) (HIMARS)

June 2, 2026 updated by: Institut Cancerologie de l'Ouest

HIghly MetAstatic Life Prolonging Therapy-Resistant Prostate Cancer: Role of Stereotactic Radiotherapy for Bone and Lymph Node Metastases

The investigators propose redefining this concept by focusing on volume rather than the number of metastases. To achieve this, the investigators aim to determine the Maximum Tolerated Volume (MTV) of metastatic lesions treatable with SRT (Stereotaxic radiotherapy) in a phase 1 study. In this study, the investigators will recruit patients with high-volume metastatic disease in bones or lymph nodes and progressively irradiate a volume-escalated subset of the total lesions. The selection will prioritize lesions at higher risk of causing pain or complications, such as fractures, spinal compression, or vascular compression. The investigators hypothesis is that SRT targeting multiple metastases (with a total volume ≤ MTV) will extend the duration without refractory pain and/or tumor-related complications in patients with castration-resistant and chemo-refractory prostate cancer.

Study Overview

Status

Status

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

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.

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 (Estimated)

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.
18

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

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Metastatic prostate cancer with clinical progression after the use of androgen-receptor pathway inhibitor, chemotherapy or any other life-prolonging therapy. Patient could have been treated previously by RadioLigand Therapy (RLT).
  • Performance Status < 3
  • Bone and/or lymph node metastases based on conventional (CT and bone scan) or metabolic imaging
  • Bone and/or lymph node metastases suitable for SRT, according to the investigator

  • Adequate organ function:

    1. Absolute Neutrophil Count (ANC) ≥ 1000/mm3 or
    2. Platelet Count ≥ 50 000/mm3 or
    3. Haemoglobin ≥ 8 g/dL (allowing transfusion or other intervention to achieve this minimum haemoglobin)
  • Age ≥ 18 years at time of study entry
  • Written informed consent obtained from the patient prior to performing any protocol-related
  • Patient is willing and able to comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations including follow up.
  • Patient has valid health insurance
  • Life time expected > 3 months

Exclusion Criteria:

  • Evidence of symptomatic metastases to the lungs, brain, peritoneum or liver
  • Evidence of diffuse metastatic spread to the bone marrow (e.g. positive super bone scan) or the cerebral spinal fluid as per bone scan (no lumbar puncture required).
  • Evidence of presence of symptomatic spinal cord compression with indication of neurosurgical decompression.
  • Patient with symptomatic and/or high-risk tumor volume-to-bone marrow reserve ratio > 50%
  • Concurrent enrolment in another clinical study, unless it is a non-therapeutic clinical study
  • Mental impairment (psychiatric illness/social situations) that may compromise the ability of the patient to give informed consent and comply with the requirements of the study;
  • Patient who has forfeited his/her freedom by administrative or legal award or who is under guardianship;
  • Patients unable to undergo medical follow-up in the study for geographical, social or psychological reasons.

  • History of another primary malignancy except for

    1. Malignancy treated with curative intent and with no known active disease ≥2 years before the first dose of SRT and of low potential risk for recurrence
    2. Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease
    3. Adequately treated carcinoma in situ without evidence of disease
  • Uncontrolled pain that contraindicates patient positioning on the radiotherapy table according to investigator
  • Patient indicated to or currently treated by cytopenic treatment as chemotherapy or RadioLigand Therapy
  • Patient under concomitant treatment that may generate severe gastro-intestinal disorder or genito-urinary disorder

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: stereotaxic radiotherapy

This volume escalation will be performed until MTV is reached.

Level cohort is defined by: volume level Irradiation volume / Bone Marrow Reserve as below:

level -1: 20% level 1 (start level): 30% level 2: 40% level 3: 50%
Radiation: Stereotactic body radiotherapy (SBRT)

The acceptable regimens are:

  • 27 Gy / 3 fractions / 3 fractions per week
  • 35 Gy / 5 fractions / 3 fractions per week An interval of at least 24 hours should be kept between two consecutive fractions.

Prescription must be defined on 80% isodose or higher, maximum dose up to 130% of the isodose prescription. At least 90% of the Planning Target Volume should receive the prescribed dose. A coverage of <90% of the Planning Target Volume will be considered as acceptable deviation, and coverage of <80% of the target volume as an Unacceptable Deviation. At least 90% of the Gross Tumoral Volume should receive the prescribed dose.

Only a part of the Gross Tumoral Volume_Total could be considered for radiation, depending on the ratio with Bone Marrow Reserve. High-risk and/or symptomatic metastases will be prioritized over other metastases.

Anatomic bone marrow reserve (BMR) will be first determined for each patient:

BMR = Total trabecular bone - (Total trabecular bone ∩ GTV_Total)

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
Maximum tolerated volume (MTV)
Time Frame: 12 weeks

The MTV will be defined as the highest volume that can be treated with an acute toxicity of grade < 3 (CTCAE V5.0 scale) in one third of patient and will allow us to determine the recommended phase II volume under the assumption that higher volumes are likely to be more toxic. The maximum tolerated Volume (MTV) is defined as the volume at which 2 Dose-Limiting Toxicity (DLT) were observed among 3 to 6 patients.

DLT are considered as:

  • Death clearly related to irradiation
  • Intractable pain despite oral or intravenous opioids and/or corticosteroids (EVA > 4 and increase of 2 from EVA baseline)

  • Any new grade ≥ 3 toxicity (CTCAE V5.0 scale) compared to baseline among:

    • Anemia
    • Febrile Neutropenia
    • Hemorrhage within grade ≥3 thrombocytopenia
    • Any gastro-intestinal-related disorder
    • Any genito-urinary-related disorder
    • Pneumonitis Bone marrow reserve will be determined by CT-base automatic tool.
12 weeks

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
Number of toxicity related to radiotherapy as assessed by CTCAE v5.0
Time Frame: through study completion
Acute (≤ 12 weeks) and late (>12 weeks) toxicity will be evaluated according to NCI-CTCAE v5 grading
through study completion
Recommended volume for irradiation by SRT for phase-II
Time Frame: 12 weeks
The Recommended Volume (RV) corresponds to the volume of the level immediately below the MTV. This Recommended Volume for irradiation by SRT will then be applied for phase 2.
12 weeks
Time to first pejorative event among tumour-related complication (bone, neurological or vascular compression) and/or death
Time Frame: 2 years
Time to first worsening event due to tumor progression (as seen on thoraco-abdomino-pelvic CT scan): including bone displacement, spinal cord or neurological compression, and vasculo-lymphatic compression will be assessed.
2 years
Number of deceased patients
Time Frame: 2 years
Overall survival is defined as the time interval between the date of registration and the date of death irrespective of the cause
2 years
Pain relief assessed by EVA scale
Time Frame: 6 months
Global pain evaluation (EVA) will be measured at baseline, 1-, 3- and 6-month following SRT. Score is 0 (no pain) to 10 (maximal pain)
6 months

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
To assess the functioning bone marrow reserve at baseline and after SRT
Time Frame: Baseline and 3 months after start of SRT
Functioning bone marrow reserve is quantified on 99Tc-sulfur colloid SPECT-CT by automatic delineation at baseline and at 3 months after SRT (GTV_Total/functioning BMR)
Baseline and 3 months after start of SRT
To compare the anatomical and functioning assessment of the bone marrow reserve
Time Frame: Baseline and 3 months after start of SRT
Comparison of the tumor volume-to-bone marrow reserve ratio: GTV_total/functioning BMR and GTV_Total/anatomic BMR
Baseline and 3 months after start of SRT

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.
Institut Cancerologie de l'Ouest

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: Loïg Vaugier, MD, ICO

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.
June 1, 2026

Primary Completion (Estimated)

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.
May 1, 2028

Study Completion (Estimated)

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.
July 1, 2030

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).
April 30, 2025

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.
May 15, 2025

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.
May 18, 2025

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.
June 4, 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.
June 2, 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

Keywords

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.
  • ICO-2024-22

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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Conditions

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