Evaluation of a New Formulation That Improves the Bioavailability and Food Effect of Abiraterone: An Open-Label, Crossover, Randomized, Controlled, Phase I Clinical Trial

Standard 1000-mg abiraterone acetate tablets, used with prednisone for metastatic prostate cancer, suffer from low and food-dependent bioavailability. This first-in-human, open-label, crossover Phase I trial evaluated RL001, a self-emulsifying soft-capsule abiraterone formulation designed to overcome these limitations, with plasma concentrations quantified by LC-MS/MS and pharmacokinetics modeled using Phoenix WinNonlin. A 200-mg dose of RL001 achieved abiraterone exposure exceeding that of the 1000-mg reference tablet while maintaining fed/fasted exposure ratios near 80% for AUC, effectively eliminating the food-related exposure spikes seen with the standard formulation; prednisone pharmacokinetics were unaffected, and hyperbilirubinemia and hypertriglyceridemia occurred less frequently. The findings suggest the abiraterone self-emulsifying soft capsule could offer a lower, more consistent therapeutic dose with an improved safety profile for prostate cancer patients.