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