Taking one-fourth the recommended dose of a standard drug with a low-fat meal is as effective as taking the recommended dose on an empty stomach for patients with castration-resistant prostate cancer, according to research published in the Journal of Clinical Oncology (2017;35[suppl 6S]:abstract 176).
Abiraterone acetate is a standard of care for the treatment of metastatic castration-resistant prostate cancer. However, previous clinical trials showed the efficacy of the drug in patients under fasting conditions. There have been no randomized continuous dosing studies that assess prandial state dosing on abiraterone acetate efficacy.
Russell Zelig Szmulewitz, MD, The University of Chicago (Illinois), and colleagues conducted a study to assess the effects of low dosing of abiraterone acetate in conjunction with food on patients with metastatic castration-resistant prostate cancer. A total of 72 patients – aged 52 to 89 years – where sampled from multiple international centers whose disease progressed despite initial hormonal therapy. Patients were randomly assigned to take the standard dose (1000 mg/day) on an empty stomach (n = 36) or the low dose (250 mg/day) with a low-fat breakfast. Changes in prostate specific antigen (PSA) response rate from baseline to week 12 of the treatment was the primary endpoint.
Results of the study showed only nominal difference in PSA levels between standard dose and low dose groups (-1.19 vs -1.59, respectively). The average time to disease progressions (14 months) was nearly identical for both arms of the study (P = .53). Additionally, patients in the low dose group were less likely to report stomach discomfort than those on the standard dose group.
Researchers concluded that a 75% reduction in dosage of abiraterone acetate, accompanied with a low-fat meal, can be just as effective as the standard dosing.
Implications of this study extend past the efficacy of the treatment. Abiraterone acetate retails for more than $9000 per month and more than 100,000 individuals in the US alone have filled prescriptions since 2011. If these individuals take the lower dose with food, the resulting 75% in cost reductions would save them more than $6 billion. A lower dose enables prescribers the spread the cost of 1 month’s prescription over 4 months – a per-patient savings of approximately $7500 per month. Thus, a lower dosing of abiraterone acetate with a low-fat meal is a more cost-effective treatment course than the standard dosing.
