This is an open label, multi-center, multiple dose Phase I study to evaluate the safety, tolerability, pharmacokinetics and efficacy of SHR-4394 injection in subjects with prostate cancer.

Inclusion Criteria:

1. Age range: 18-85 years old, male;
2. ECOG score for physical condition is 0-1 points;
3. Expected survival period ≥ 6 months;
4. Prostate adenocarcinoma confirmed by histological or cytological examination;
5. Patients with at least one metastasis lesion;
6. Disease progression on or after the most-recent prior regimen;
7. Continuous treatment with luteinizing hormone releasing hormone analogues (LHRHa) or previous bilateral orchidectomy;
8. Testosterone was at castration level;
9. Adequate organ function.

Exclusion Criteria:

1. Received systemic anticancer treatments or clinical investigational drugs 4 weeks prior to the initiation of the study treatment;
2. Unresolved to CTCAE 5.0>=grade 2 toxicities from previous anticancer therapy;
3. Meningeal metastasis history or clinical symptoms of central nervous system metastasis;
4. Uncontrollable tumor-related pain;
5. Uncontrolled pleural effusion, pericardial effusion, or abdominal effusion with clinical symptoms;
6. Other serious concomitant disease;
7. Previous or co-existing malignancies;
8. History of severe hypersensitivity reactions to either the drug substances or inactive ingredients of SHR-4394;
9. Active hepatitis B or active hepatitis C;
10. Other inappropriate situation considered by the investigator.