Androgen-responsive POSLUMA-guided Intra-prostatic Boost

NCT07393867 | Recruiting Phase 2 DMC FDA Drug

• 1 other identifier: 25-708
• Study Type: interventional
• Target: 23
• Locations: 1 country
• Sites: 4

Brief Summary

This research study is for men with intermediate- or high-risk prostate cancer who are planning to receive hormone therapy and radiation treatment. The purpose of the study is to see whether a special type of diagnostic imaging done during hormone therapy can help doctors more accurately target remaining cancer with radiation, while avoiding areas that may no longer need extra treatment. All participants will receive standard hormone therapy and radiation therapy, along with three imaging scans, over a six-month period. The information gained from this study may help make prostate cancer radiation treatment more precise and reduce side effects for future patients.

Conditions

Intermediate Risk Prostate Cancer; High Risk Prostate Cancer; Prostate Cancer

Keywords

POSLUMA; prostate-specific membrane antigen positron-emission tomography; PSMA-PET/CT; 18F-flotufolastat-PSMA-PET/CT scan; ADT and 18F-flotufolastat-guided focal SBRT microboost; androgen deprivation therapy and 18F-flotufolastat-guided focal SBRT microboost; neoadjuvant ADT; neoadjuvant androgen deprivation therapy; neoadjuvant ADT prior to SBRT; 18F-flotufolastat-PET/CT scans for intermediate and high risk prostate cancer

Outcome Measures

Primary Outcomes (1)

• Percentage of patients with GTV treatment contours that are highly concordant with GTV-combined interim.

  To evaluate whether \>50% of patients will be treated utilizing GTV contours that are highly concordant with those from interim PET/MR scans (GTV-combined-interim) based on the dice coefficient

  8 weeks from initiation of hormone therapy/before start of radiation therapy

Secondary Outcomes (4)

• Geometric accuracies of GTV-Combined-Baseline and GTV-combined-interim contours

  8 weeks from initiation of hormone therapy/before start of radiation therapy

• PSA response

  8 weeks from initiation of hormone therapy and 24 weeks from initiation of hormone therapy (end of treatment)

• PSMA PET response

  8 weeks from initiation of hormone therapy and 24 weeks from initiation of hormone therapy (end of treatment)

• MRI ADC contrast ratio

  8 weeks from initiation of hormone therapy

Study Arms (1)

ADT + SBRT + PSMA PET/CT Imaging

EXPERIMENTAL

* ADT as prescribed * PSMA PET/CT imaging will be completed at baseline, 8 weeks after ADT start, and at end of treatment * SBRT is administered starting 10 weeks after ADT start

Diagnostic Test: PSMA PET/CT; Drug: Androgen Deprivation Therapy (ADT) +/- bicalutamide; Radiation: Stereotactic Body Radiation Therapy (SBRT) +/- focal microboost

Interventions

PSMA PET/CT DIAGNOSTIC_TEST

PSMA PET/CT is an imaging test that uses a radioactive tracer to highlight prostate cancer cells. Imaging will be performed at baseline, approximately eight weeks after starting ADT, and approximately 24 weeks after starting ADT (end of treatment). These scans are used to guide radiation treatment planning and assess treatment response.

ADT + SBRT + PSMA PET/CT Imaging

Androgen Deprivation Therapy (ADT) +/- bicalutamide DRUG

ADT is used to lower testosterone levels, which can slow or shrink prostate tumors. All participants will receive approximately six months of ADT starting before radiation therapy, using injectable or oral medications. Depending on the type of ADT, participants may also receive daily bicalutamide. Bicalutamide is categorized as an antiandrogen, which means it will block the effects of testosterone and work together with ADT to slow down or shrink prostate cancer.

ADT + SBRT + PSMA PET/CT Imaging

Stereotactic Body Radiation Therapy (SBRT) +/- focal microboost RADIATION

SBRT is a form of radiation therapy that delivers precise, high-dose radiation to the prostate over a short period of time. SBRT will be initiated 10 weeks after initiation of ADT and will be delivered in five sessions over two weeks. Based on PSMA PET/CT and MRI findings after initiation of ADT, some participants may receive an optional focal radiation microboost to areas of residual cancer. The microboost, if delivered, will be given during the same SBRT treatment sessions and will be limited by standard safety constraints.

ADT + SBRT + PSMA PET/CT Imaging

Eligibility Criteria

• Age: 18 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• years of age and older.
• Eastern Oncology Group Status 0 to 1.
• Histologic diagnosis of prostate cancer.
• Prior screening MRI with at least one PI-RADS4 or PI-RADS 5 lesion, obtained within 180 days of screening.
• NCCN intermediate-risk or high-risk prostate cancer (Appendix B). All patients will be staged by MRI.
• Prior PSMA PET scan with at least one focal avid lesion greater than background prostate that is concordant with a lesion on MRI, obtained within 180 days of screening.
• Intention for SBRT (36.25 Gy/5 fraction) with focal boost (up to 50 Gy) to one MRI/PET-concordant lesion34.

You may not qualify if:

• Prior imaging (CT, bone scan, MRI, PSMA-PET/CT) showing nodal or distant disease.
• Intention to receive treatment intensification with secondary androgen receptor signaling inhibitors or chemotherapy.
• Clinical T4 disease.
• Prior ADT.
• Prior pelvic RT.
• Prior prostate surgery, including TURP.
• International prostate symptom score \> 20.
• Prior urethral stricture.
• Prostate volume \> 80 cc on MRI.
• Hip implants that cause artifacts over the prostate gland.
• Inability to discontinue anti-coagulation for fiducial marker placement.
• Active Crohn's disease or scleroderma.

Sponsors & Collaborators

• Martin T. King, MD, PhD: lead
• Blue Earth Diagnostics: collaborator
• Dana-Farber/Brigham and Women's Cancer Center: collaborator

Study Sites (4)

Brigham and Women's Hospital

Boston, Massachusetts, 02115, United States

NOT YET RECRUITING

Dana Farber Cancer Institute

Boston, Massachusetts, 02115, United States

NOT YET RECRUITING

Dana-Farber/Brigham and Women's Cancer Center at Milford Regional Medical Center

Milford, Massachusetts, 01757, United States

RECRUITING

Dana-Farber/Brigham and Women's Cancer Center in Clinical Affiliation with South Shore Hospital

Weymouth, Massachusetts, 02190, United States

RECRUITING

MeSH Terms

Conditions

Prostatic Neoplasms

Interventions

Androgen Antagonists; bicalutamide; Radiosurgery

Condition Hierarchy (Ancestors)

Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Intervention Hierarchy (Ancestors)

Hormone Antagonists; Hormones, Hormone Substitutes, and Hormone Antagonists; Physiological Effects of Drugs; Pharmacologic Actions; Chemical Actions and Uses; Radiotherapy; Therapeutics; Stereotaxic Techniques; Neurosurgical Procedures; Surgical Procedures, Operative; Investigative Techniques

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Director, Brachytherapy Clinical Operations, Associate Professor of Radiation Oncology, Harvard Medical School

Study Record Dates

• First Submitted: January 27, 2026
• First Posted: February 6, 2026
• Study Start: April 29, 2026
• Primary Completion (Estimated): December 15, 2026
• Study Completion (Estimated): December 15, 2027
• Last Updated: May 29, 2026

Record last verified: 2026-05

Locations

US (4)