Abiraterone Therapy for Castrate-Resistant Prostate Cancer

Introduction to Abiraterone Therapy

The National Comprehensive Cancer Network recommends abiraterone acetate 1,000 mg once daily plus prednisone 5 mg twice daily as a Category 1 treatment for castrate-resistant prostate cancer, significantly improving overall survival 1, 2

The American College of Physicians and other guideline societies support the use of abiraterone acetate 1,000 mg orally once daily on an empty stomach plus prednisone 5 mg twice daily, with an alternative dosing of 250 mg once daily with a low-fat breakfast considered to reduce financial toxicity and improve compliance, though this is a Category 2B recommendation 1, 3
Maintaining castrate testosterone levels is critical, and the principle remains the same even after bilateral orchiectomy, with the goal of keeping testosterone levels below 50 ng/dL 1, 4

In men with metastatic CRPC who received prior docetaxel, abiraterone plus prednisone significantly improved overall survival compared to prednisone alone, with a median overall survival of 14.8 vs 10.9 months, representing the strongest evidence base and FDA approval for post-chemotherapy CRPC 5
For asymptomatic or minimally symptomatic patients, abiraterone is a standard option based on improved radiographic progression-free survival and overall survival in the COU-AA-302 trial 6

The survival benefit of abiraterone was larger in men under 70 years of age than in older men, with a hazard ratio of 0.51 vs 0.94, and older men experienced increased toxicities with higher incidences of grade 3-5 adverse events and treatment-related deaths 1, 2, 3

Baseline assessment should include blood pressure, serum potassium, liver function tests, and cardiac evaluation 1, 2
Ongoing monitoring should include regular checks for mineralocorticoid excess effects, such as hypertension and hypokalemia, as well as hepatotoxicity and cardiac disorders 1, 2, 5, 7

Common adverse events include joint swelling, hypokalemia, edema, muscle discomfort, hot flush, diarrhea, urinary tract infection, cough, hypertension, and arrhythmia, with an overall discontinuation rate due to adverse events of approximately 12% 2, 3, 5

The European Society for Medical Oncology (ESMO) recommends abiraterone or enzalutamide as first-line options for asymptomatic/mildly symptomatic chemotherapy-naïve mCRPC patients (Level I, A evidence) 8, 9
The National Comprehensive Cancer Network (NCCN) designates abiraterone as a Category 1 recommendation for first-line treatment of asymptomatic or mildly symptomatic chemotherapy-naïve mCRPC patients, indicating high-level evidence and uniform consensus 10
Abiraterone acetate 1,000 mg orally once daily plus prednisone 5 mg orally twice daily is a Category 1 first-line treatment option for metastatic castration-resistant prostate cancer (mCRPC), particularly for asymptomatic or mildly symptomatic patients who have not received prior chemotherapy 8, 11

Severe hypertension or cardiac disorders occur in approximately 10% of patients 10
Grade 3-5 liver toxicity occurs in approximately 7% of patients 10
The survival benefit is larger in men <70 years (HR 0.51) compared to older men (HR 0.94) 10
Older men experience significantly higher rates of grade 3-5 adverse events (47% vs 33%) and treatment-related deaths (9 vs 3) 10

For chemotherapy-naïve mCRPC, abiraterone is a first-line standard of care alongside enzalutamide 8, 11, 9
The choice between abiraterone and enzalutamide should be based on patient comorbidities, side effect profiles, and patient preference 8