NCT03503344

Apalutamide With or Without Stereotactic Body Radiation in Treating Castration-Resistant Prostate Cancer

A Randomized, Phase II Study of Apalutamide +/- Stereotactic Body Radiotherapy (SBRT) in Castration-Resistant Prostate Cancer Patients With Oligometastatic Disease on PSMA-PET Imaging

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 26 (actual)
• Sponsor: University of California, San Francisco · Academic / Other
• Sex: Male
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

This phase II trial studies the how well apalutamide with or without stereotactic body radiation therapy work in treating participants with castration-resistant prostate cancer. Testosterone can cause the growth of prostate cancer cells. Hormone therapy using apalutamide may fight prostate cancer by blocking the use of testosterone by the tumor cells. Stereotactic body radiation therapy uses special equipment to position a patient and deliver radiation to tumors with high precision. This method can kill tumor cells with fewer doses over a shorter period and cause less damage to normal tissue. It is not yet known whether giving apalutamide with or without stereotactic body radiation therapy works better in treating participants with castration-resistant cancer.

Detailed description

PRIMARY OBJECTIVE: I. To demonstrate whether the proportion of patients with an undetectable serum prostate specific antigen (PSA) at 6 months following cessation of apalutamide is higher with addition of stereotactic body radiation therapy (SBRT) to prostate specific membrane antigen (PSMA)-avid oligometastatic sites of disease compared to the group of patients receiving apalutamide monotherapy SECONDARY OBJECTIVES: I. To compare the time to PSA progression by Prostate Cancer Working Group (PCWG) criteria between treatment arms. II. To evaluate the safety and tolerability of apalutamide in combination with SBRT. EXPLORATORY OBJECTIVES: I. To characterize the metastatic pattern at baseline and at progression in these patients and to determine whether features of the baseline PSMA-PET scan are associated with treatment outcomes. OUTLINE: Participants are randomized to 1 of 2 arms. ARM A: Participants receive apalutamide PO QD on days 1-28. Courses repeat every 28 days for up to 52 weeks in the absence of disease progression or unacceptable toxicity. ARM B: Participants receive apalutamide orally (PO) once daily (QD) on days 1-28. Courses repeat every 28 days for up to 52 weeks in the absence of disease progression or unacceptable toxicity. Beginning 60 days after first dose of apalutamide, participants also undergo stereotactic body radiation therapy for 1-5 fractions. After completion of study treatment, participants are followed at for 30 days.

Conditions

• Castration Levels of Testosterone
• Castration-Resistant Prostate Carcinoma
• PSA Progression
• Stage IV Prostate Adenocarcinoma AJCC v7

Interventions

Type	Name	Description
DRUG	Apalutamide	Given PO, 240 mg per day (4 x 60mg tablets)
RADIATION	Stereotactic Body Radiation Therapy	Undergo SBRT

Timeline

• Start date: 2019-12-17
• Primary completion: 2024-12-31
• Completion: 2025-10-31
• First posted: 2018-04-19
• Last updated: 2026-01-21
• Results posted: 2026-01-21

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study