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.

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.

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.