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NCT Number: NCT06978296

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

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.

Recruiting

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Key information

Age range

18 year and older

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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:
  • Absolute Neutrophil Count (ANC) ≥ 1000/mm3 or
  • Platelet Count ≥ 50 000/mm3 or
  • 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
  • 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
  • Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease
  • 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

Treatment and study plan

Stereotactic body radiotherapy (SBRT)

Radiation

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)

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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

  2. 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.

  3. 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)

  4. 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.

  5. 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

Other outcomes

  1. 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)

  2. 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

Study contacts

Contact information is provided by the study sponsor or research team.

Loïg Vaugier, MD

CONTACT

[email protected]

+33240679900

Lucie Labarre

CONTACT

[email protected]

Sponsors and collaborators

Lead sponsor

Institut Cancerologie de l'Ouest

Other

Registry information

Official study title

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

Acronym: HIMARS

Important dates

Study start
2026
Primary completion
2028
Study completion
2030
First posted
May 18, 2025
Registry last updated
Jun 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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