Comparative Study of Abiraterone Acetate Tablets (I) or ZYTIGA® in Patients With Metastatic Castration-resistant Prostate Cancer

Inclusion criteria

• Males, ≥ 18 years old;
• Histologically or cytologically diagnosed with prostate adenocarcinoma, without neuroendocrine or small cell characteristics, and having metastatic lesions with imaging evidence (such as positive bone scan or metastatic lesions on CT/MRI);
• Serum testosterone level < 50 ng/dL or 1.7 nmol/L at the screening; subjects who have not undergone bilateral orchidectomy must plan to continue medication throughout the study to maintain therapy with effective GnRH agonist or antagonist;
• Progression of prostate cancer as confirmed by diagnostic files, meeting one of the conditions for disease progression: 1) Biochemistry evidence of recurrence: continuous 3 rises of PSA (taken a minimum of 1 week apart) from a baseline measurement of at least 2 ng/mL, greater than 50% of the minimum value in 2 rises; 2) Radiographic progression: a clear evidence of new lesion; 2 or more new bone lesions appearing on bone scan; CT or MRI showing lesion progression (RECIST 1.1);
• ECOG performance status score of ≤ 1;
• Life expectancy of ≥ 6 months;
• Major organs are functioning well

Exclusion criteria

• History of pituitary or adrenal dysfunction;
• Have used flutamide within 4 weeks before the first dose of study treatment, and bicalutamide or nilutamide within 6 weeks before the first dose of study treatment;
• Prior therapy with CYP17 inhibitors (such as abiraterone acetate, ketoconazole, TAK-700, etc.) or investigational drugs or marketed drugs of new androgen receptor antagonists (such as enzalutamide, apalutamide, SHR3680, ODM-201, and proxalutamide);
• Have received 5-reductase inhibitors (such as finasteride and dutasteride), estrogen, progesterone, any herbal products (such as saw palmetto) that may decrease PSA levels, and radiotherapy within 4 weeks prior to the start of study medication;
• Have previously received biotherapy or cytotoxic chemotherapy for mCRPC; patients who have completed docetaxel treatment for at least 1 year before enrollment can participate in screening;
• Prostate cancer with moderate to severe pain symptoms, with a score of > 3 for Question 3 (the worst pain in the last 24 hours, 0-1 point means asymptomatic, 2-3 points mean mild symptoms) of the Brief Pain Inventory-Short Form (BPI-SF);
• With contraindications to the use of glucocorticoids, such as uncontrolled persistent infections or other conditions;
• Chronic diseases that require systemic corticosteroid therapy (> 10 mg/day prednisone or equivalent). Patients who have discontinued the administration or reduced the dose to < 10 mg within 14 days prior to the start of study treatment are eligible;
• Presence of abdominal fistula, gastrointestinal perforation, abdominal abscess, or other abnormal gastrointestinal function within 6 months before the first dose of study treatment, which may affect drug absorption as judged by the investigator;
• Presence of active heart disease within 6 months prior to the first dose of study treatment, including: severe/unstable angina, myocardial infarction, symptomatic congestive heart failure, left ventricular ejection fraction < 50%, and severe arrhythmia requiring treatment or New York Heart Association (NYHA) Class III-IV heart failure;
• Inability to swallow the whole tablet;
• Other conditions that make the patient unsuitable for the study as judged by the investigator.