• Males aged ≥18 years at screening and voluntary to participate in the study and sign the informed consent form.

• Subjects with histologically or cytologically confirmed prostate adenocarcinoma, with no small cell features.

• In the case of medical or surgical castration, during or after the last treatment before screening, there are signs of progressive disease determined according to the PCWG3 criteria, defined as satisfying one or more of the following 3 criteria:

∙ PSA progression; at least 2 episodes of increased PSA levels that are measured ≥1 week apart; PSA ≥ 1 μg/L (1 ng/mL) in the screening period;

‣ Progression of soft tissue lesions as defined by RECIST 1.1;

‣ The progression of bone lesions is defined as at least two new lesions discovered by bone scan; ambiguous results can be confirmed using another imaging technique (e.g., CT or MRI).

• Metastatic diseases confirmed by imaging examinations during the screening period (the status of metastasis refers to the presence of metastatic lesions confirmed by bone scan and/or CT/MRI scan).

• For patients who have undergone orchiectomy or are being treated by medical castration therapy, their androgen blockade therapy is maintained by luteinizing hormone-releasing hormone agonists or antagonists during the study period (including the follow-up period), and their serum testosterone levels are ≤ 1.73 nmol/L (50 ng/dL) during screening visits.

• Patients who have failed previous treatments of prostate cancer with abiraterone acetate or who are intolerant to treatments with abiraterone acetate.

• Patients who have failed previous chemotherapy of prostate cancer with docetaxel or who are intolerant to treatments with docetaxel, or who are not suitable for docetaxel treatment during screening. Patients who are not suitable for docetaxel treatment during screening and do not plan to use cytotoxic chemotherapy within 6 months after the informed discussion are eligible.

• Expected survival of ≥ 3 months.

• ECOG performance status score of 0-2.

⁃ Laboratory tests must meet the following criteria:

• Blood routine examination: Hemoglobin (Hb) ≥ 85 g/L; white blood cell (WBC) ≥ 3.0 x 109/L; platelet (PLT) ≥ 75 x 109/L;

∙ Liver function: Total bilirubin (TBIL) ≤ 1.5 x ULN; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 x ULN (for patients without liver metastasis) or ≤ 5 x ULN (for patients with liver metastasis); albumin (ALB) ≥ 25 g/L;

∙ Renal function: serum creatinine (SCr) ≤ 1.5 x ULN.

⁃ Willing to use reliable contraceptive measures (such as condoms) and not to donate sperms throughout the study period and within 3 months after the last dose.