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

January 16, 2026 updated by: Rahul Aggarwal, University of California, San Francisco

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

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.

Study Overview

Status

Status

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

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.

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.

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 (Actual)

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.
26

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.
  • Phase 2

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.
  • Name: UCSF Genitourinary Cancer Clinical Trials Recruitment
  • Phone Number: 877-827-3222
  • Email: GUTrials@ucsf.edu

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94115
        • University of California, San Francisco

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Histologically or cytologically confirmed adenocarcinoma of the prostate
  • Progressive, castration-resistant prostate cancer demonstrated during continuous antiandrogen therapy (ADT), defined as 3 PSA rises at least 1 week apart, with a minimum PSA > .05 ng/mL obtained during screening.
  • At least one but no more than 5 discrete PSMA-avid radiation fields on baseline PSMA-PET scan; all PSMA-avid lesions in radiation fields must be amenable to SBRT in judgment of treating radiation oncologist; there are no restrictions on site of lesion/radiation fields (e.g. bone, lymph node, prostate, visceral). Equivocal lesions/radiation fields on PSMA PET scan that are not definitive for metastasis will not count towards the limit of 5 radiation fields and will not undergo SBRT
  • Surgically or medically castrated, with testosterone levels of < 50 ng/dL during screening; if the patient is medically castrated, continuous dosing with luteinizing hormone-releasing hormone (LHRH) analogue must have been initiated at least 4 weeks prior to randomization and must be continued throughout the study to maintain castrate levels of testosterone including post-treatment follow up period
  • No prior systemic treatment initiated for the treatment of castration resistant prostate cancer, including abiraterone acetate, enzalutamide, apalutamide, darolutamide, other novel AR or CYP17 antagonist, or docetaxel.
  • Patients receiving bone loss prevention treatment with bone-modifying agents (e.g. denosumab, zoledronic acid) must be on stable doses for at least 4 weeks prior to randomization
  • Patients who received a first generation anti-androgen (e.g., bicalutamide, flutamide, nilutamide) as most recent treatment must have at least a 6-week washout prior to randomization and must show continuing disease (PSA) progression (an increase in PSA) after washout
  • At least 4 weeks or 5 half-lives, whichever is shorter, must have elapsed from the use of any anti-cancer therapy, other than Luteinizing hormone-releasing hormone (LHRH) analog or first generation antiandrogen, prior to randomization
  • At least 4 weeks must have elapsed from major surgery or radiation therapy prior to randomization
  • Age > 18 years
  • Eastern Cooperative Oncology Group (ECOG) performance status grade 0 or 1
  • Resolution of all acute toxic effects of prior therapy or surgical procedure to grade 1 or baseline prior to randomization
  • Serum aspartate transaminase (AST) ((serum glutamic oxaloacetic transaminase (SGOT])) and serum alanine transaminase (ALT) (( serum glutamic pyruvic transaminase (SGPT)) ≤ 2.5 x upper limit of normal (ULN)
  • Total serum bilirubin ≤ 1.5 x ULN; in subjects with known or suspected Gilbert's syndrome, if total bilirubin is > 1.5 x ULN, direct bilirubin is ≤ 1.5 x ULN
  • Glomerular filtration rate ≥ 45 ml/min based on Cockcroft-Gault equation
  • Absolute neutrophil count (ANC) ≥ 1500/microliter
  • Platelets ≥ 75,000/microliter without transfusion and/or growth factors in the 3 months prior to randomization
  • Hemoglobin ≥ 9.0 g/dL without transfusion and/or growth factors in the 3 months prior to randomization
  • Serum albumin ≥ 3.0 g/dL
  • Signed and dated informed consent document indicating that the patient has been informed of all pertinent aspects of the trial prior to randomization
  • Willingness and ability to comply with scheduled visits, treatment plans, laboratory and radiographic assessments, and other study procedures, including ability to swallow study drug tablets and long-term follow-up
  • Agrees to use a condom (even men with vasectomies) and another effective method of birth control if he is having sex with a woman of childbearing potential or agrees to use a condom if he is having sex with a woman who is pregnant while on study drug and for 3 months following the last dose of study drug; must also agree not to donate sperm during the study and for 3 months after receiving the last dose of study drug

Exclusion Criteria:

  • Presence of visceral lesions (e.g. lung, liver) detectable on baseline imaging or bone lesions requiring focal radiation treatment at the time of study entry
  • History of seizure or condition that may pre-dispose to seizure (e.g., prior stroke within 1 year prior to randomization, brain arteriovenous malformation, Schwannoma, meningioma, or other benign central nervous system (CNS) or meningeal disease which may require treatment with surgery or radiation therapy
  • Concurrent therapy with any of the following (all must have been discontinued or substituted for at least 1 week prior to randomization, except for medications known to lower seizure threshold which must be discontinued or substituted at least 4 weeks prior to randomization)
  • Medications known to lower the seizure threshold
  • Herbal (e.g., saw palmetto) and non-herbal (e.g., pomegranate) products that may decrease PSA levels
  • Systemic (oral/intravenous (IV)/intramuscular (IM)) corticosteroids; patients on chronic stable dose of steroids at an equivalent dose of prednisone ≤ 10 mg daily may be permitted to enroll at the discretion of principal investigator
  • Any other experimental treatment on another clinical trial
  • Any of the following within 6 months prior to randomization: Severe/unstable angina, myocardial infarction, symptomatic congestive heart failure, arterial or venous thromboembolic events (e.g., pulmonary embolism, cerebrovascular accident including transient ischemic attacks), or clinically significant ventricular arrhythmias
  • Uncontrolled hypertension at study entry; patients with a history of uncontrolled hypertension are allowed provided blood pressure is controlled by antihypertensive treatment
  • Gastrointestinal disorder affecting absorption
  • Secondary malignancy requiring active treatment except for non-melanoma skin cancer and superficial bladder cancer
  • Any medical condition that would be a contra-indication to radiation therapy, such as inflammatory bowel disease
  • Spinal cord compression or impending spinal cord compression
  • Any other condition that, in the opinion of the Investigator, would impair the patient's ability to comply with study procedures

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: Randomized
  • Interventional Model: Parallel 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: Arm A (apalutamide monotherapy)
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.
Drug: Apalutamide
Given PO, 240 mg per day (4 x 60mg tablets)
Other Names:
  • ARN 509
  • JNJ 56021927
Experimental: Arm B (apalutamide, SBRT)
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. Beginning 60 days after first dose of apalutamide, participants also undergo stereotactic body radiation therapy for 1-5 fractions.
Radiation: Stereotactic Body Radiation Therapy
Undergo SBRT
Other Names:
  • SBRT
  • SABR
  • Stereotactic Ablative Body Radiation Therapy
Drug: Apalutamide
Given PO, 240 mg per day (4 x 60mg tablets)
Other Names:
  • ARN 509
  • JNJ 56021927

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
Proportion of Participants With Undetectable Serum Prostate-specific Antigen (PSA)
Time Frame: Approximately 18 months from date of randomization
The primary endpoint for the study is the proportion of participants with undetectable serum PSA (< 0.2 ng/mL) at 6 months following completion of apalutamide therapy (18 months from date of randomization). Participants who discontinue apalutamide prior to completion of 12 months of therapy for reasons other than disease progression by Prostate Cancer Clinical Trials Working Group (PCWG) criteria, as well as participants who withdraw or are lost to follow up, will be considered unevaluable for this analysis. Participants who discontinue treatment for radiographic or clinical progression, even if occurring prior to receipt of Stereotactic radiation therapy (SBRT) in the experimental arm), would be evaluable for analysis of the primary endpoint.
Approximately 18 months from date of randomization

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
Median Time to PSA Progression
Time Frame: Up to 36 months
Time to a diagnosis of PSA progression defined by the Prostate Cancer Working Group (PCWG) criteria will be estimated using Kaplan-Meier methods for each treatment arm and will be used to estimate the median time to progression and 95% confidence interval (CI).
Up to 36 months
Number of Participants With Treatment-related Adverse Events (AEs)
Time Frame: Up to 36 months
For each treatment arm, adverse event incidence per group will be summarized by severity (highest grade) for those AEs judged by the Investigator to be probably, possibly, or definitely related to the study treatment and will be summarized by frequency and percentage, with all participants treated in that treatment arm as the denominator unless otherwise specified. In addition, Adverse events with missing severity or relationship to study drug will be classified as severe and treatment-related, respectively.
Up to 36 months

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.
University of California, San Francisco

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Janssen Pharmaceuticals

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: Rahul Aggarwal, MD, University of California, San Francisco

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.
December 17, 2019

Primary Completion (Actual)

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.
December 31, 2024

Study Completion (Actual)

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.
October 31, 2025

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 11, 2018

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.
April 11, 2018

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.
April 19, 2018

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.
January 21, 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.
January 16, 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.
January 1, 2026

More Information

Terms related to this study

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.
  • 175519
  • NCI-2018-00572 (Registry Identifier: NCI Clinical Trials Reporting Program (CTRP))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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