Background: Owing to efficacy and tolerability, abiraterone acetate (AA) is a leading treatment for men with metastatic castration-resistant prostate cancer. Increased serum concentrations of AA, such as by taking AA with food, may lead to the inhibition of additional enzymes in the androgen synthesis pathway implicated in castration-resistant prostate cancer progression.
Methods: Medical records of men with metastatic castration-resistant prostate cancer (mCRPC) who received AA between 1 April 2011 and 31 December 2013 were retrospectively reviewed. The primary outcome was the percent of men with a rising PSA on AA who experienced any PSA decline within 3 months after changing the administration of AA from without food to with food. Secondary outcomes were median time on AA therapy in men who received AA therapy without food versus those that switched administration from without food to with food at PSA progression, and the percent of men who experienced any decline in serum testosterone concentration, and the rate of adverse events observed while taking AA with food.
Results: Nineteen men who switched AA administration from without food to with food and 41 patients who administered AA without food only were included in the study. Of those patients who took AA with food at PSA progression, a PSA decline was observed in 3 of the 19 (16%) men, including 3 of the 14 men who had an initial response to AA (21%). Testosterone declined in five out of seven patients from pre-food levels. The median time on AA therapy was increased by nearly 100 days in patients who switched AA administration from without food to with food. No increases in toxicity were observed.
Conclusion: Some men with mCRPC may benefit from taking AA with food. Further prospective comparative studies are needed to determine if changing AA administration is beneficial.