An Exploratory Clinical Study Evaluating the Safety and Efficacy of Allogeneic CAR-NK Cell Therapy for Metastatic Castration-resistant Prostate Cancer (mCRPC)

Inclusion Criteria: * Age ≥ 18 years, male; * Diagnosis of metastatic castration-resistant prostate cancer (mCRPC) meeting the following criteria: ① Serum testosterone at castration level: \< 50 ng/dL or \< 1.7 nmol/L; ② Meeting any one of the following conditions: a. PSA progression: Three consecutive rises in PSA measured at intervals of at least 1 week, with two increases being ≥ 50% above the PSA nadir, and a PSA value \> 2 ng/mL; b. Radiographic progression: Two or more new lesions detected on bone scan, or an increase in soft tissue lesions assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST). * Expected survival ≥ 6 months; * ECOG performance status of 0-2; * Positive prostate-specific membrane antigen (PSMA) expression; * Voluntarily participate, provide written informed consent, and be able to comply with follow-up. Exclusion Criteria: * Prior treatment with other cell therapy products besides the investigational product, such as dendritic cells (DC), cytokine-induced killer cells (CIK), T cells, natural killer cells (NK), chimeric antigen receptor T-cell immunotherapy (CAR-T), etc.; * History of other malignancies within 5 years prior to screening (except for completely resolved carcinoma in situ or malignancies deemed by the investigator to be slow-progressing); * Abnormal function of major organs: a. Absolute neutrophil count (ANC) \< 1.5 × 10⁹/L; Platelet count (Plt) \< 100 × 10⁹/L; Hemoglobin (Hb) \< 9 g/dL; b. Liver function: Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) ≥ 2.5 × the upper limit of normal (ULN) (or ≥ 5 × ULN for subjects with liver metastases); c. Renal function: Serum creatinine (Cr) ≥ 1.5 × ULN; d. Coagulation function: Prothrombin time (PT), Activated partial thromboplastin time (APTT), International Normalized Ratio (INR) ≥ 1.5 × ULN; * Any currently treated active (viral, bacterial, fungal) infection, or any infection within the past 6 weeks requiring intravenous antibiotics for 7 days or longer, or any active infection requiring oral antibiotics within the past week; * Active autoimmune disease, or history of severe autoimmune disease requiring long-term immunosuppressive therapy; * Participation in another clinical trial study within 3 months; * Inability to employ effective contraceptive measures; * History of hypersensitivity to biologic macromolecular drugs; * Untreated chronic active hepatitis B, or chronic hepatitis B virus carriers with HBV DNA ≥ 1000 copies/mL, or patients with active hepatitis C; * Subjects deemed by the investigator to be unsuitable for participation in this study for other reasons.