PROstate Cancer TReatment Optimization Via Analysis of Circulating Tumour DNA

Phase 2

Active, not recruiting

• Conditions: Metastatic Castration-Resistant Prostate Cancer (mCRPC)
• Interventions: Drug: Enzalutamide; Drug: Docetaxel

• Registration Number: NCT04015622
• Lead Sponsor: British Columbia Cancer Agency

Brief Summary

The purpose of this study is to assess the strategy in treatment selection using ctDNA fraction as a predictive biomarker to direct treatment decision (ctDNA fraction \<2% receives enzalutamide, and ctDNA fraction ≥2% receives docetaxel) versus clinician's choice of enzalutamide or docetaxel, in subjects with metastatic castration-resistant prostate cancer post abiraterone setting.

Detailed Description

This is a prospective, open-label, phase II trial with 1:1 randomization to either Arm A biomarker directed therapy (patients with ctDNA fraction \<2% receive enzalutamide, and ctDNA fraction ≥2% receive docetaxel), versus Arm B clinician's choice of enzalutamide or docetaxel, in subjects with metastatic castration-resistant prostate cancer post abiraterone. At time of progression, patient will cross-over to the other therapy (e.g., enzalutamide to docetaxel, and docetaxel to enzalutamide).

Study Timeline

• Study First Submitted: 2019-07-09
• Study First Submitted QC: 2019-07-09
• Study First Posted: 2019-07-11
• Study Start: 2020-10-07
• Status Verified: 2025-08
• Last Update Submitted: 2025-08-15
• Last Update Posted: 2025-08-20
• Primary Completion: 2026-04-01
• Study Completion: 2026-12-01

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: Male
• Target Recruitment: 100

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
A: Biomarker directed Therapy (BT)	Docetaxel	ctDNA fraction \<2% receives enzalutamide, and ctDNA fraction ≥2% receives docetaxel until disease progression, then cross-over to the other therapy (e.g., enzalutamide to docetaxel, or docetaxel to enzalutamide).
B: Clinician's Choice (CC)	Enzalutamide	Enzalutamide or docetaxel until disease progression, then cross-over to the other therapy (e.g., enzalutamide to docetaxel, or docetaxel to enzalutamide).
A: Biomarker directed Therapy (BT)	Enzalutamide	ctDNA fraction \<2% receives enzalutamide, and ctDNA fraction ≥2% receives docetaxel until disease progression, then cross-over to the other therapy (e.g., enzalutamide to docetaxel, or docetaxel to enzalutamide).
B: Clinician's Choice (CC)	Docetaxel	Enzalutamide or docetaxel until disease progression, then cross-over to the other therapy (e.g., enzalutamide to docetaxel, or docetaxel to enzalutamide).

Primary Outcome Measures

Name	Time	Method
Progression free survival (PFS)	1 year	PFS is defined as the time between the date of starting trial treatment to any of the following: clinical, PSA, radiographic progression, or death from any cause on first-line therapy

Secondary Outcome Measures

Name	Time	Method
Objective response	1 year	To determine the objective response as per RECIST 1.1 in patients treated with biomarker directed therapy vs. clinician's choice.
Correlation of specific ctDNA-based genomic alterations to treatment response	1 year	Among mCRPC patients receiving enzalutamide and docetaxel
Second progression free survival (PFS2)	1 year	PFS2 is defined as the time elapsed between the date of treatment commencement and the first documented evidence of any disease progression or death from any cause from cross-over second-line therapy.
Clinical benefit rate (CBR)	3 months	CBR is defined as PSA or measurable radiological response of any duration or stable disease for ≥ 12 weeks (no symptomatic progression, PSA progression, or objective disease progression).
PSA response rate	1 year	PSA response rate is defined as the proportion of patients with a PSA decline (defined as a ≥30%, ≥50% and other declines in PSA from baseline) in mCRPC patients treated with biomarker directed therapy vs. clinician's choice.
Overall survival (OS)	2 years	OS is defined as time from treatment commencement to death of any cause of mCRPC patients treated with biomarker directed therapy vs. clinician's choice.

Trial Locations

Locations (14)

BC Cancer - Centre for the North; 🇨🇦 Prince George, British Columbia, Canada

BC Cancer - Kelowna (Sindi Ahluwalia Hawkins Centre); 🇨🇦 Kelowna, British Columbia, Canada

BC Cancer - Surrey Centre; 🇨🇦 Surrey, British Columbia, Canada

Sunnybrook Health Sciences Centre; 🇨🇦 Toronto, British Columbia, Canada

BC Cancer - Vancouver Centre; 🇨🇦 Vancouver, British Columbia, Canada

BC Cancer - Victoria Centre; 🇨🇦 Victoria, British Columbia, Canada

London Health Sciences Centre; 🇨🇦 London, Ontario, Canada

BC Cancer - Kelowna (Sindi Ahluwalia Hawkins Centre); 🇨🇦 Kelowna, British Columbia, Canada

BC Cancer - Centre for the North; 🇨🇦 Prince George, British Columbia, Canada

BC Cancer - Surrey Centre; 🇨🇦 Surrey, British Columbia, Canada

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