Darxicilib Combined With Abiraterone Acetate Tablets (II) for the Treatment of Advanced Metastatic Castration-resistant Prostate Cancer.

Inclusion Criteria:

* Age ≥18 years old, male;
* ECOG performance status score of 0 to 1;
* Life expectancy of at least 3 months;
* Histologically or cytologically confirmed adenocarcinoma of the prostate, without a diagnosis of neuroendocrine or small cell carcinoma;
* Testosterone at castrate levels at screening (≤50 ng/dL or 1.73 nmol/L);
* Failure of previous treatment with new androgen receptor antagonists at the mHSPC stage (such as enzalutamide, apalutamide, ODM-201, SHR3680, HC-1119, and pucrol);
* Capable of complying with the study protocol as judged by the investigator;

Exclusion Criteria:

* Previously received abiraterone acetate treatment for prostate cancer;
* Previously received any cytotoxic chemotherapy for mCRPC stage;
* Previously received treatment with any other cyclin-dependent kinase 4 and 6 (CDK4 \& 6) inhibitors;
* Previously received treatment with new androgen receptor antagonists at the mCRPC stage (such as enzalutamide, apalutamide, ODM-201, SHR3680, HC-1119, and pucrol);
* The washout period from the end of any previous anti-tumor treatment (including radiotherapy, surgery, molecular targeted therapy, immunotherapy, and first-generation androgen receptor antagonists) to the first administration of this study is less than 4 weeks (except for bicalutamide with a washout period less than 6 weeks);