Strategic Endocrine Therapy and Targeted Radiotherapy for Prostate Cancer

NCT07364071 | Not Yet Recruiting Phase 2 DMC

• 1 other identifier: 813314
• Study Type: interventional
• Target: 150
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to study definitive external beam radiation therapy together with drugs called androgen deprivation therapy (ADT) in patients with prostate cancer. The investigators want to find out if these drugs work the same way if they are given for 6 months or for the usual 18 months in patients who receive also definitive external beam radiotherapy. The investigators will also learn about the safety of the treatments. The main questions the study aims to answer are: Do patients who get radiation therapy plus 6 months of androgen deprivation therapy need other hormone therapy or develop castration resistance at a higher rate within 5 years, compared to patients who get radiation therapy plus 18 months of androgen deprivation therapy? Participants will: Be treated with definitive external beam radiation therapy and receive androgen deprivation therapy for 6 months or 18 months. Have visits once every 3 months for checkups and tests for at least 5 years. The visits at 3 months, 1 year, and 5 years need to be done in person; all the other visits can be done in person or remotely (telehealth). Keep a diary of the missed doses of the androgen deprivation therapy.

Conditions

Prostate Adenocarcinoma

Keywords

Radiotherapy; Androgen deprivation therapy; Prostate cancer

Outcome Measures

Primary Outcomes (1)

• Failure-free survival

  To compare failure-free survival of radiotherapy plus short-term androgen deprivation therapy plus, if indicated, an androgen receptor pathway inhibitor to that of radiotherapy plus long-term androgen deprivation therapy. Participants will be considered to have failure-free survival if they do not experience any of the events in the 5 years after the end of radiation therapy: 1. Death from any cause. 2. Initiation of salvage hormone therapy as defined in the protocol. 3. Castration resistance per the Prostate Cancer Clinical Trials Working Group 3 definition. Castration resistance is defined as biochemical or clinical progression - as defined in the protocol - while serum testosterone is at castrate levels (\<50 ng/dL).

  Within 5 years

Study Arms (2)

RT + ST-ADT

EXPERIMENTAL

Radiotherapy with short-term androgen deprivation therapy (6 months) plus, if indicated, an androgen receptor pathway inhibitor.

Radiation: Radiation therapy

RT + LT-ADT

ACTIVE COMPARATOR

Radiotherapy with long-term androgen deprivation therapy (18 months).

Radiation: Radiation therapy

Interventions

Radiation therapy RADIATION

Radiotherapy with short-term androgen deprivation therapy plus, if indicated, an androgen receptor pathway inhibitor.

RT + LT-ADT; RT + ST-ADT

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Only patients with prostate cancer can be enrolled.
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Histologically confirmed adenocarcinoma of the prostate.
• High-risk localized prostate cancer, defined as ≥1 of the following (per National Comprehensive Cancer Network or D'Amico criteria):
• Prostate specific antigen ≥ 20 ng/mL
• Gleason score 8-10
• Clinical stage T3a or higher; imaging can be used to determine T stage if there is macroscopic (gross) extraprostatic extension or invasion of the seminal vesicles or other non-prostate organs
• No evidence of distant metastasis, confirmed by:
• a. Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) or equivalent staging imaging
• Planning to receive definitive external beam radiotherapy and hormone therapy as standard of care (on label or medically accepted) treatment
• Eastern Cooperative Oncology Group performance status 0-1.
• Age ≥ 18 years.
• Willingness to use adequate contraception if sexually active and of reproductive potential
• Ability to understand and willingness to sign informed consent.
• Stated willingness to comply with all study procedures and availability for the duration of the study.

You may not qualify if:

• Evidence of metastatic disease, including nodal disease beyond the pelvis or distant metastases on imaging.
• Clear evidence of regional nodal disease on conventional imaging.
• Prior prostatectomy.
• Prior systemic therapy for prostate cancer, including:
• Androgen deprivation therapy (Note that participants who have started Androgen deprivation therapy within 90 days prior to randomization can be enrolled.)
• Androgen receptor pathway inhibitor (e.g., abiraterone, enzalutamide, apalutamide, darolutamide).
• Chemotherapy for prostate cancer.
• Prior pelvic radiotherapy.
• Any condition that, in the investigator's judgment, would compromise the patient's safety or compliance.

Sponsors & Collaborators

• Lantheus: collaborator
• University of California, San Diego: lead

Study Sites (1)

University of California San Diego

La Jolla, California, 92093, United States

Location

MeSH Terms

Conditions

Prostatic Neoplasms

Interventions

Radiotherapy

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)

Therapeutics

Study Officials

• Tyler Seibert, MD, PhD

  University of California, San Diego

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Tyler Seibert, MD, PhD

CONTACT

(858) 822-5354; cancerCTO@health.ucsd.edu

Genitourinary Research Team

CONTACT

(858) 822-5354; cancerCTO@health.ucsd.edu

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Radiation Oncologist

Study Record Dates

• First Submitted: January 15, 2026
• First Posted: January 23, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): April 1, 2031
• Study Completion (Estimated): April 1, 2034
• Last Updated: January 27, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)