Safety, Tolerability, and Efficacy of CP-PCA07 in Combination With Enzalutamide in Patients With Castration-Resistant Prostate Cancer

An Open-Label, Dose-Escalation, Multicenter Phase 1 Study to Evaluate the Safety, Tolerability, and Efficacy of CP-PCA07 in Combination With Enzalutamide in Patients With Castration-Resistant Prostate Cancer

The purpose of this clinical study is to evaluate the safety, tolerability, and efficacy of CP-PCA07 in combination with enzalutamide in patients with castration-resistant prostate cancer (CRPC).

This is an open-label, dose-escalation, multicenter Phase 1 study. The primary objective is to assess the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) to determine the recommended Phase 2 dose (RP2D) of the combination therapy.

The secondary objective is to assess changes in Prostate-Specific Antigen (PSA) levels and pharmacokinetic characteristics.

Exploratory objectives include assessment of tumor response, disease control, progression-free survival, and biomarker analyses, including AR-V7 status, according to RECIST version 1.1 and other applicable criteria.

Study Overview

• Status: Not yet recruiting
• Conditions: Castration-Resistant Prostate Cancer (CRPC)
• Intervention / Treatment: Drug: CP-PCA07; Drug: Enzalutamide 40 mg capsule

Detailed Description

This is an open-label, single-arm, multicenter Phase 1, 3+3 dose-escalation study evaluating CP-PCA07 administered in combination with enzalutamide in patients with castration-resistant prostate cancer (CRPC). A 12-week dose-limiting toxicity (DLT) evaluation period will be implemented for each cohort. A Safety Review Committee (SRC) will function as the independent body for safety monitoring and dose-escalation decisions.

• Study Type: Interventional
• Enrollment (Estimated): 18
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Hyundai Bioscience Clinical Trial Inquiries; Phone Number: +82-1544-3194; Email: clinical@hyundaibio.com

Study Locations

• South Korea
  • Seoul, South Korea, 03080
    • Seoul National University Hospital
    • Principal Investigator: Chang Wook Jeong, MD, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 1. Male patients aged ≥19 years at the time of providing written informed consent.
• 2. Patients with histologically or cytologically confirmed castration-resistant prostate cancer without small-cell features, who have experienced treatment failure with monotherapy of Enzalutamide or Abiraterone.
• 3. Patients with a serum testosterone level < 50 ng/dL at screening.
• 4. Patients with an increase in PSA compared to baseline, confirmed by two consecutive measurements within 8 weeks prior to the date of written informed consent (with at least 1 week between measurements and an increase of ≥ 50% compared to baseline).
• 5. Patients with PSA levels ≥ 2 ng/mL both prior to the date of written informed consent and at screening.
• 6. Patients with an ECOG performance status ≤ 2 and an expected survival of at least 6 months.
• 7. Patients whose spouse or partner is a woman of childbearing potential must agree to use one of the protocol-specified highly effective methods of contraception from the time of study participation consent until 3 months after the last administration of the investigational product.
• 8. Patients who voluntarily agree to participate in this study and provide written informed consent.

Exclusion Criteria:

• 1. Patients who have received chemotherapy, chemoradiotherapy, biologic therapy, immunotherapy, or radiotherapy within 4 weeks prior to the first administration of the investigational product (for docetaxel or cabazitaxel therapy, within 9 weeks prior to the screening date).
• 2. Patients diagnosed with immunodeficiency or who are in an immune-suppressed condition.
• 3. Patients with autoimmune diseases.
• 4. Patients with a pacemaker or severe heart failure [Class III or IV heart failure according to the New York Heart Association (NYHA) classification], or patients with uncontrolled arrhythmia (all patients with implanted medical devices other than a pacemaker are excluded).
• 5. Patients with a history of chronic liver disease or evidence of cirrhosis.
• 6. Patients with a history of gastrectomy or other conditions that may affect drug absorption.
• 7. Patients with a history of deep vein thrombosis, pulmonary embolism, acute coronary syndrome, or major cerebrovascular disease within 6 months prior to screening.
• 8. Patients with a history of major surgery requiring general anesthesia or assisted ventilation within 4 weeks prior to screening.
• 9. Patients with active hepatitis B, a history of hepatitis B, or known active hepatitis C virus infection at screening.
• 10. Patients who meet any of the following laboratory criteria at screening:
• ① Absolute neutrophil count (ANC) < 1,500/uL without G-CSF administration within 2 weeks prior to screening
• ② Platelet < 100,000/uL without transfusion within 2 weeks prior to screening
• ③ Hemoglobin < 9.0 g/dL without transfusion within 2 weeks prior to screening
• ④ Serum creatinine > 1.8 mg/dL or eGFR (or GFR) < 40 mL/min/1.73 m2
• ⑤ AST and ALT > 2.5 x ULN
• ⑥ Total bilirubin > 2.0 x ULN
• 11. Patients expected to have hypersensitivity to the active ingredient or components of the investigational product.
• 12. Patients who have received another investigational drug or investigational medical device within 4 weeks prior to the first administration of the investigational product.
• 13. Patients deemed by the investigator to be unsuitable for participation in the study or unable to comply with the study requirements due to other diseases or conditions.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Enzalutamide + CP-PCA07; Patients will receive combination therapy with CP-PCA07 and Enzalutamide. Enzalutamide will be administered orally once daily at a fixed dose of 160 mg. CP-PCA07 will be administered orally three times daily, starting at 600 mg/day, with planned dose escalation to 900 mg/day and 1,200 mg/day according to the protocol-specified 3+3 dose-escalation criteria and dose-limiting toxicity evaluation.

Drug: CP-PCA07; CP-PCA07 will be administered orally three times daily. The starting dose is 600 mg/day, with planned escalation to 900 mg/day and 1,200 mg/day based on protocol-specified 3+3 dose-escalation criteria and dose-limiting toxicity evaluation.; Other Names: Niclosamide; Drug: Enzalutamide 40 mg capsule; Enzalutamide will be administered orally once daily at a fixed dose of 160 mg, with or without food, in combination with CP-PCA07.; Other Names: Xtandi

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recommended Phase 2 Dose (RP2D) Based on Maximum Tolerated Dose (MTD) and Dose-Limiting Toxicity (DLT)	The recommended Phase 2 dose (RP2D) will be determined by assessing the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) using a 3+3 dose-escalation design. Safety and tolerability data collected during the first 12 weeks of treatment in each dose cohort will be evaluated by the Safety Review Committee (SRC)	Up to 12 weeks after the first dose of the combination therapy

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Baseline in Prostate-Specific Antigen (PSA) Levels	Descriptive statistics will be presented for the changes in Prostate-Specific Antigen (PSA) levels from baseline to each evaluated post-baseline time point.	Baseline, Week 1 (Day 8), Week 2 (Day 15), Week 4 (Day 29), Week 8 (Day 57), and Week 12 (Day 85)
Maximum Observed Plasma Concentration (Cmax and Cmax,ss) of Niclosamide, Metabolite M1, and Enzalutamide	To determine the peak plasma concentration (Cmax) at Day 1 and steady-state peak plasma concentration (Cmax,ss) at Day 29 for Niclosamide (administered as CP-PCA07), its metabolite M1, and Enzalutamide.	Day 1 and Week 4 (Day 29): pre-dose, and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, and 8 hours post-dose
Area Under the Plasma Concentration-Time Curve (AUCt and AUCtau) of Niclosamide, Metabolite M1, and Enzalutamide	To evaluate the area under the plasma concentration-versus-time curve from time zero to the last quantifiable concentration (AUCt) at Day 1 and during a dosing interval at steady state (AUCtau) at Day 29 to assess systemic exposure.	Day 1 and Week 4 (Day 29): pre-dose, and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, and 8 hours post-dose
Time to Maximum Observed Plasma Concentration (Tmax and Tmax,ss) of Niclosamide, Metabolite M1, and Enzalutamide	To measure the time to reach maximum plasma concentration (Tmax) at Day 1 and steady-state maximum plasma concentration (Tmax,ss) at Day 29.	Day 1 and Week 4 (Day 29): pre-dose, and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, and 8 hours post-dose
Elimination Half-life (t1/2) of Niclosamide, Metabolite M1, and Enzalutamide	To estimate the terminal elimination half-life (t1/2) of Niclosamide, its metabolite M1, and Enzalutamide, where mathematically feasible based on the plasma concentration-time profile.	Day 1 and Week 4 (Day 29): pre-dose, and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, and 8 hours post-dose

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate (ORR)	The objective response rate is defined as the proportion of patients who achieve a Complete Response (CR) or Partial Response (PR) at the evaluated time points, assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.	At 4, 8, and 12 weeks after the first dose of combination therapy
Disease Control Rate (DCR)	The Disease Control Rate is defined as the proportion of patients with Complete Response (CR), Partial Response (PR), or Stable Disease (SD) at 12 weeks after administration, assessed according to RECIST 1.1 criteria.	At 12 weeks after the first dose of combination therapy
Incidence of New Metastases	Descriptive statistics will be presented for the incidence and evaluation of new tumor metastases using RECIST 1.1 criteria.	Before administration (Baseline) and at 12 weeks after the first dose of combination therapy

Collaborators and Investigators

• Sponsor: Hyundai Bioscience Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: June 23, 2026
• First Submitted That Met QC Criteria: July 2, 2026
• First Posted (Actual): July 6, 2026

Study Record Updates

• Last Update Posted (Actual): July 6, 2026
• Last Update Submitted That Met QC Criteria: July 2, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Phase 1; Dose escalation; Castration-resistant prostate cancer; Enzalutamide; CRPC; Niclosamide; CP-PCA07
• Additional Relevant MeSH Terms: Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Salicylanilides; Salicylamides; Niclosamide; enzalutamide
• Other Study ID Numbers: ADM-PC-001

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: No
• Studies a U.S. FDA-regulated device product: No