Does a food intervention makes abiraterone treatment affordable?

Abstract

e16523 Background: Abiraterone is registered for metastatic prostate cancer. It is used in a fixed oral dose of 1000mg OD in a fasted state in combination with 10mg prednisone daily. Although large differences in the effect of food on abiraterone exposure are reported (ranging from 1-10 fold increase in area under the concentration time curve (AUC)) it is generally accepted that abiraterone is much better absorbed in the presence of food. By administering abiraterone with food a reduced dose can be given while maintaining equivalent abiraterone exposure. Moreover aadministering abiraterone with food is more patient friendly and it could significantly reduce the treatment costs of abiraterone.The aim of this study was to establish the bio-equivalent lower dose of abiraterone when taken with a continental breakfast compared to the standard intake of 1000mg OD in fasted state. Methods: In this phase I cross-over multi-center study abiraterone pharmacokinetics (PK) were evaluated in patients with metastatic prostate cancer who were treated with 1000 mg abiraterone in a fasted state, followed by 500 mg taken with a continental breakfast. After both periods of 14 days, abiraterone plasma exposure was measured. Bioequivalence was assumed when the GMR (fed/fasted) of the AUC0-24h and Cmax and their 90% confidence interval (CI) were within the range of 0.8 and 1.7. Results: 14 patients were enrolled into the study, of whom 12 were eligible for PK analysis. GMR (fed/fasted) AUC0-24h was 0.88 (90% CI 0.73-1.07), GMR Cmax was 1.03 (CI 0.79-1.34) and the GMR of Ctrough was 0.81 (90% CI 0.60-1.10). Conclusions: Ingesting 500mg abiraterone with a continental breakfast was not considered bio-equivalence when compared to 1000mg taken fasted. The criteria for bio-equivalence could not be met due to the large variability in pharmacokinetics of abiraterone within and between patients. Due to this large variability in abiraterone exposure, we believe that dose optimization by food intake is not a feasible strategy for abiraterone. The intake of abiraterone with food could not be advised based on the results presented in our study. Clinical trial information: NCT02883166. [Table: see text]