PLX2853 in Combination With Abiraterone Acetate and Prednisone and in Combination With Olaparib in Subjects With Metastatic Castration-Resistant Prostate Cancer (mCRPC)

April 7, 2025 updated by: Opna Bio LLC

A Multicenter, Open-Label, Parallel, Phase 1b/2a Study of PLX2853 in Combination With Abiraterone Acetate and Prednisone and Phase 1b/2a Study of PLX2853 in Combination With Olaparib in Subjects With Metastatic Castration-Resistant Prostate Cancer (mCRPC)

The purpose of this research study is to evaluate safety, pharmacokinetics, pharmacodynamics and preliminary efficacy of the investigational drug PLX2853 in subjects with Metastatic Castration-Resistant Prostate Cancer (mCRPC)

Study Overview

Status

Status

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

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.

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.
19

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
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
      • London, United Kingdom, W1G 6AD
        • Sarah Cannon Research Institute
  • United States
    • Illinois
      • Chicago, Illinois, United States, 60637
        • University of Chicago
    • Michigan
      • Detroit, Michigan, United States, 48201
        • Karmanos Cancer Institute
    • New York
      • New York, New York, United States, 10032
        • Columbia University Medical Center
    • South Carolina
      • Myrtle Beach, South Carolina, United States, 29572
        • Carolina Urologic Research Center
    • Tennessee
      • Nashville, Tennessee, United States, 37203
        • Tennessee Oncology/ Sarah Cannon
    • Virginia
      • Fairfax, Virginia, United States, 22031
        • Virginia Cancer Specialist
    • Wisconsin
      • Madison, Wisconsin, United States, 53792
        • University of Wisconsin

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:

  1. Age ≥18 years at the time of signing informed consent.
  2. Histologically confirmed adenocarcinoma of the prostate with tumor tissue available for molecular analyses.
  3. Eastern Cooperative Oncology Group Performance Status 0 to 1.
  4. Adequate organ function as demonstrated following laboratory values.
  5. Fertile male subjects with female sexual partners must agree to use a highly effective method of birth control during the study and for 90 days after the last dose of study drug.
  6. Except as specified above for organ function, all drug-related toxicity from previous cancer therapy (including ongoing Abiraterone Acetate + Prednisone therapy if applicable) must be resolved (to Grade ≤1 or baseline per National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0) prior to study treatment administration (Grade 2: alopecia, hot flashes, decreased libido, or neuropathy is allowed).
  7. Willingness and ability to provide written informed consent prior to any study-related procedures and to comply with all study requirements.

Exclusion Criteria:

  1. Prior exposure to a bromodomain inhibitor.
  2. History of autoimmune hemolytic anemia or autoimmune thrombocytopenia.
  3. Clinically significant cardiac disease.
  4. Inability to take oral medication or significant nausea and vomiting, malabsorption, or significant small bowel resection that, in the opinion of the Investigator, would preclude adequate absorption.

  5. Active known second malignancy with the exception of any of the following:

    • Adequately treated basal cell carcinoma or squamous cell carcinoma of the skin.
    • Adequately treated Stage I cancer from which the subject is currently in remission and has been in remission for ≥2 years.
    • Any other cancer from which the subject has been disease-free for ≥3 years.
  6. Subject is participating in any other therapeutic clinical study (observational or registry studies are allowed).
  7. Presence of any other medical, psychological, familial, sociological, or geographic condition potentially hampering compliance with the study protocol or would interfere with the study endpoints or the subject's ability to participate in the study in the judgment of the Investigator.
  8. Receipt of any anti-cancer therapy prior to Cycle 1 Day 1 with less than protocol defined wash-out with the exception of Abiraterone Acetate (for subjects enrolling into Abiraterone Acetate Combination) and GnRH therapy.

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: Non-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: Phase 1b PLX2853 (20 mg) + Olaparib
Phase 1b dose escalation
Drug: Olaparib
Olaparib tablets
Drug: PLX2853 20 mg
PLX2853 tablets
Experimental: Phase 1b PLX2853 (40 mg) + Abiraterone Acetate + Prednisone
Phase 1b dose escalation
Drug: Abiraterone acetate
Abiraterone acetate tablets
Drug: Prednisone
Prednisone (or equivalent) tablets
Drug: PLX2853 40 mg
PLX2853 tablets
Experimental: Phase 1b PLX2853 (80 mg) + Abiraterone Acetate + Prednisone
Phase 1b dose escalation
Drug: Abiraterone acetate
Abiraterone acetate tablets
Drug: Prednisone
Prednisone (or equivalent) tablets
Drug: PLX2853 80 mg
PLX2853 tablets
Experimental: Phase 2a PLX2853 (80 mg) + Abiraterone Acetate + Prednisone
Phase 2a dose expansion
Drug: Abiraterone acetate
Abiraterone acetate tablets
Drug: Prednisone
Prednisone (or equivalent) tablets
Drug: PLX2853 80 mg
PLX2853 tablets
Experimental: Phase 1b PLX2853 (40 mg) + Olaparib
Phase 1b dose escalation
Drug: Olaparib
Olaparib tablets
Drug: PLX2853 40 mg
PLX2853 tablets

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
Number of Participants With Dose-Limiting Toxicities
Time Frame: From time of first dose of PLX2853 and combination agent(s) through completion of Cycle 1 (21 days)
Dose limiting toxicity defined as clinically significant adverse events or laboratory abnormalities occurring during first cycle of study drug administration that are possibly related to study drug and that meet specific criteria defined in the protocol
From time of first dose of PLX2853 and combination agent(s) through completion of Cycle 1 (21 days)
Phase 1b (Both Arms): Incidence of TEAEs That Are Related to Treatment
Time Frame: From time of first dose of PLX2853 and combination agent(s) until 30 days from end of treatment (an average of 103 days)
Treatment-emergent adverse events are those reported after study drug has been administered.
From time of first dose of PLX2853 and combination agent(s) until 30 days from end of treatment (an average of 103 days)
Determination of Maximum Tolerated Dose
Time Frame: From time of first dose of PLX2853 and combination agent(s) through completion of Cycle 1 (21 days)
To be evaluated in both PLX2853 + AA + pred and PLX2853 + olap group; If DLTs observed in 2 or more subjects the dose will be considered intolerable and MTD will have been reached.
From time of first dose of PLX2853 and combination agent(s) through completion of Cycle 1 (21 days)

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
Radiographic progression-free survival (rPFS) (both arms, both phases)
Time Frame: From 6 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Radiographic progression-free survival (PFS) will be calculated for each subject as the number of days from the first day of PLX2853 and combination agent(s) treatment (Cycle 1 Day 1) to the date of the first documented disease progression by either RECIST v.1.1 or on bone scan.
From 6 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Time to PSA Progression (both arms, both phases)
Time Frame: From 3 weeks of treatment (Cycle 2 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
PSA progression (defined per PCWG3 as a ≥25% increase and an absolute increase of ≥2 ng/mL above the nadir, which is confirmed by a second consecutive value obtained 3 or more weeks later).
From 3 weeks of treatment (Cycle 2 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Duration of PSA Response (both arms, both phases)
Time Frame: From 3 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Duration of PSA response will be calculated for each subject with a PSA response as the time from date of first documented, confirmed response (CR or PR) using PCWG3 until date of documented progression confirmed at least 3 weeks later, or death from any cause.
From 3 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Overall Survival (OS) (both arms, both phases)
Time Frame: From time of first dose until completion of long term follow-up, approximately 30 months.
Overall survival (OS) will be calculated for each subject as the number of days from the first day of PLX2853 treatment and combination agent(s) (Cycle 1 Day 1) to the date of death from any cause. If a subject is lost to follow-up, OS is censored at the date of last contact.
From time of first dose until completion of long term follow-up, approximately 30 months.
Incidence of all TEAEs (both arms, both phases)
Time Frame: From time of first dose of PLX2853 and combination agent(s) until 30 days from end of treatment.
From time of first dose of PLX2853 and combination agent(s) until 30 days from end of treatment.
Incidence of TEAEs that result in dose interruption, reduction or discontinuation (both arms, both phases)
Time Frame: From time of first dose of PLX2853 and combination agent(s) until 30 days from end of treatment.
From time of first dose of PLX2853 and combination agent(s) until 30 days from end of treatment.
PLX2853 PK parameter AUC0-24 (both arms, both phases)
Time Frame: From time of first dose until 30 days from end of treatment.
AUC from time zero extrapolated to 24 hours (AUC0-24)
From time of first dose until 30 days from end of treatment.
PLX2853 PK parameter Cmax (both arms, both phases)
Time Frame: From time of first dose until 30 days from end of treatment.
Maximum observed concentration
From time of first dose until 30 days from end of treatment.
PLX2853 PK parameter T1/2 (both arms, both phases)
Time Frame: From time of first dose until 30 days from end of treatment.
terminal elimination half-life (T1/2)
From time of first dose until 30 days from end of treatment.
Best Overall Response (BOR) (both arms, both phases)
Time Frame: From 6 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Best Overall Response (BOR) per RECIST v1.1 will be calculated for each subject with a minimum interval for confirmation of CR and PR of 4 weeks.
From 6 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Duration of Response (DOR) (both arms, both phases)
Time Frame: From 6 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Time from date of first documented, confirmed response using RECIST v1.1 and PCWG3 until date of documented progression or death from any cause.
From 6 weeks of treatment (Cycle 3 Day 1; 21 days per cycle) until completion of long term follow-up, an average of 6 months.
Time to first Symptomatic Skeletal-Related Event (SSRE) (both arms, both phases)
Time Frame: From time of first dose until 30 days from end of treatment.

Time to first Symptomatic Skeletal-Related Event (SSRE) defined as:

  • Use of radiation therapy to prevent or relieve skeletal symptoms.
  • Occurrence of new symptomatic pathological bone fractures (vertebral or non-vertebral). Radiologic documentation is required.
  • Occurrence of spinal cord compression. Radiologic documentation required.
  • Orthopedic surgical intervention for bone metastasis.
From time of first dose until 30 days from end of treatment.

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.
Opna Bio LLC

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.
September 21, 2020

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.
May 24, 2022

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.
May 24, 2022

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).
September 14, 2020

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.
September 14, 2020

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.
September 21, 2020

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.
April 8, 2025

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.
April 7, 2025

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.
April 1, 2025

More Information

Terms related to this study

Keywords

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.
  • PLX124-04

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

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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