Stein CA, et al. - Herein, authors comparatively examined the therapeutic equivalence, steady-state pharmacokinetics, and safety of a novel abiraterone acetate fine particle formulation (AAFP) 500 mg plus methylprednisolone with the originator AA (OAA) 1,000 mg plus prednisone, in men with metastatic castrate-resistant prostate cancer (mCRPC). Findings affirmed the therapeutic equivalence between AAFP 500 mg daily and OAA 1,000 mg daily based on serum testosterone levels, in mCRPC patients. Similar prostate-specific antigen (PSA)-50 response rates were revealed by both agents. Data reported similar abiraterone trough levels between treatments. No new safety concerns were revealed.