A Safety and Efficacy Study of SHR3680 in Metastatic Castration-Resistant Prostate Cancer Patients

Inclusion Criteria: * ECOG performance scale 0 - 1. * Life expectancy of more than 6 months. * Histologically or cytologic confirmed prostate adenocarcinoma without neuroendocrine differentiation or small cell features * Ongoing androgen deprivation therapy with a gonadotropin releasing hormone (GnRH) analogue or orchiectomy * Evidence of prostate cancer progression by radiographic or PSA criteria * Radiological evidence of distant metastatic lesions * Serum testosterone level \< 1.7 nmol/L (50 ng/dL) at the screening visit * Adequate hepatic, renal, heart, and hematologic functions (platelets \> 80 × 10e9/L, neutrophil \> 1.5 × 10e9/L, Hb \>90 g/L,total bilirubin and creatinine within upper limit of normal(ULN), and serum transaminase≤1.5×the ULN). * Signed and dated informed consent.Willingness and ability to comply with scheduled visits, treatment plans, laboratory tests, and other study procedure. Exclusion Criteria: * Treatment with androgen receptor antagonists, 5-alpha reductase inhibitors, estrogens, or chemotherapy within 4 weeks of enrollment or plans to initiate treatment with any of these drugs during the study * Prior treatment with enzalutamide, abiraterone, or ketoconazole for prostate cancer * History of seizure or any conditions that may predispose to seizure * Concurrent or planned treatment with corticosteroids, medications known to have seizure potential, or herbal products known to decrease PSA levels * Planned to initiate any other anti-tumor therapies during the study * Less than 4 weeks from the last clinical trial * Evidence of brain metastasis or primary tumors * Clinically significant cardiovascular diseases * Abuse of alcohol or drugs * Severe concurrent disease, infection, or bone metastasis that, in the judgment of the investigator, would make the patient inappropriate for enrollment