Assessment of the Safety of Glucocorticoid Regimens in Combination With Abiraterone Acetate for Metastatic Castration-Resistant Prostate Cancer

Abstract

Key Points Question What are the physiological effects associated with abiraterone acetate plus various glucocorticoid regimens to treat metastatic castration-resistant prostate cancer? Findings In this open-label, phase 2 randomized clinical trial, the 164 men with metastatic castration-resistant prostate cancer treated with abiraterone acetate plus prednisone, 5 mg, twice or once daily, 2.5 mg twice daily, or dexamethasone, 0.5 mg, once daily showed no mineralocorticoid excess toxic effects (grade ≥1 hypokalemia or grade ≥2 hypertension) through cycle 6. Insulin resistance and loss of total body bone mineral density at the end of study were only significant with dexamethasone. Meaning Lowering glucocorticoid dose combined with abiraterone acetate requires careful monitoring for toxic effects related to mineralocorticoid excess.