ZEN003694 and Enzalutamide Versus Enzalutamide Monotherapy in Metastatic Castration-Resistant Prostate Cancer

Recruiting now · Phase 2

Conditions studied: Metastatic Castration-Resistant Prostate Cancer

In brief

This is an open-label, randomized, Phase 2b study of ZEN003694 in combination with enzalutamide vs. enzalutamide monotherapy in patients with mCRPC who have progressed on prior abiraterone by PCWG3 criteria. Disease must have progressed on only abiraterone by PCWG3 criteria prior to study entry. The patient population will be separated into two cohorts: Cohort A: Patients with poor response to prior abiraterone defined as: * Abiraterone started in hormone-sensitive prostate cancer (HSPC) disease setting: \< 12 months duration on abiraterone or failure to achieve PSA nadir of 0.2 ng/mL while taking abiraterone, or; * Abiraterone started in castrate-resistant prostate cancer (CRPC) disease setting: \< 6 months duration on abiraterone or failure to achieve PSA50 response while on abiraterone Cohort B: Patients with response to prior abiraterone, defined as: * Abiraterone started in hormone-sensitive prostate cancer (HSPC) disease setting: ≥ 12 months duration on abiraterone and nadir PSA \< 0.2 ng/mL, or; * Abiraterone started in castrate-resistant prostate cancer (CRPC) disease setting: ≥ 6 months duration on abiraterone and confirmed PSA50 response

Key facts

Study ID: NCT04986423
Run by: Zenith Epigenetics
People needed: 200
Starts: 2021-09-08
Expected to finish: 2027-06-01
Last updated by the study team: 2026-05-08

Who can join

Age: 18 and older. Sex: male. Healthy volunteers: not accepted.

You may qualify if…

Males age ≥ 18 years
Metastatic, castration-resistant, histologically confirmed prostate cancer
Surgical castration or continuous medical castration for ≥ 8 weeks prior to screening; serum testosterone < 50 ng/dL confirmed within 4 weeks of first administration of study drug
Have progressed on prior abiraterone treatment by PCWG3 criteria
Patients who are not candidates for chemotherapy in the opinion of the investigator or patients who decline chemotherapy
Cohort A only - Patient must meet definition of poor responder to abiraterone by one of the following:
Abiraterone started in hormone-sensitive prostate cancer (HSPC) disease setting: < 12 months duration on abiraterone or failure to achieve PSA nadir of 0.2 ng/mL while taking abiraterone
Abiraterone started in castrate-resistant prostate cancer (CRPC) disease setting: < 6 months duration on abiraterone or failure to achieve a PSA50 response
Cohort B only - Patient must meet definition of responder to abiraterone by one of the following:
Abiraterone started in hormone-sensitive prostate cancer (HSPC) disease setting: ≥ 12 months duration on abiraterone and nadir PSA < 0.2 ng/mL
Abiraterone started in castrate-resistant prostate cancer (CRPC) disease setting: ≥ 6 months duration on abiraterone and PSA50 response
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

You may not qualify if…

Any history of brain metastases, prior seizure, conditions predisposing to seizure activity
Have previously received an investigational BET inhibitor (including previous participation in this study or a study of ZEN003694)
Receipt of prior second-generation androgen receptor inhibitors (e.g. enzalutamide, apalutamide, darolutamide, proxalutamide). Receipt of first-generation AR antagonists (e.g. bicalutamide, nilutamide, flutamide) does not count towards this limit.
Have received prior chemotherapy in the metastatic castration-resistant setting (prior chemotherapy in the hormone-sensitive setting is allowed provided last dose was at least 6 months prior to first dose of study drug)
Have received prior systemic anti-cancer therapy within 2 weeks or five half-lives, whichever is shorter, prior to the first administration of study drug
Have received exogenous administration of testosterone therapy since discontinuation of abiraterone.
Failure to recover to Grade 1 or lower toxicity related to prior systemic therapy (excluding alopecia and neuropathy) prior to study entry
Radiation therapy within 2 weeks of the first administration of study drug

Where it is running

Zhejiang Provincial People's Hospital — Hangzhou, Zhejiang, China (enrolling)
University of California, San Francisco — San Francisco, California, United States (enrolling)
Innovative Clinical Research Institute — Whittier, California, United States (enrolling)
Colorado Urology — Lakewood, Colorado, United States (enrolling)
D&H Cancer Research Center, LLC — Margate, Florida, United States (enrolling)
BRCR Global — Plantation, Florida, United States (enrolling)
First Hospital of Shanxi Medical University — Taiyuan, Shanxi, China (enrolling)
Sichuan Provincial People's Hospital — Chengdu, Sichuan, China (enrolling)
California Research Institute — Los Angeles, California, United States (enrolling)
Maryland Oncology Hematology, P.A. — Columbia, Maryland, United States (enrolling)
University of Michigan Rogel Cancer Center — Ann Arbor, Michigan, United States (enrolling)
Messino Cancer Center — Asheville, North Carolina, United States (enrolling)
Northwest Cancer Specialists, P.C. — Portland, Oregon, United States (enrolling)
Urology Associates, P.C. — Nashville, Tennessee, United States (enrolling)
Texas Oncology - Central South — Austin, Texas, United States (enrolling)
Virginia Cancer Specialists — Fairfax, Virginia, United States (enrolling)
Seattle Cancer Care Alliance — Seattle, Washington, United States (enrolling)
Anhui Provincial Hospital — Hefei, Anhui, China (enrolling)
Chongqing Cancer Hospital — Chongqing, Chongqing Municipality, China (enrolling)
The First Affiliated Hospital of Xiamen University — Xiamen, Fujian, China (enrolling)
Henan Cancer Hospital — Zhengzhou, Henan, China (enrolling)
Tongji Hospital of Tongji Medical College, Huazhong University of Science & Technology — Wuhan, Hubei, China (enrolling)
Hubei Cancer Hospital — Wuhan, Hubei, China (enrolling)
Hunan Cancer Hospital — Changsha, Hunan, China (enrolling)
Nanjing Drum Tower Hospital — Nanjing, Jiangsu, China (enrolling)

Full record on ClinicalTrials.gov

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