You have accessJournal of UrologyProstate Cancer: Advanced II1 Apr 2014MP70-11 IMPACT OF PRIOR ENDOCRINE THERAPY ON CLINICAL BENEFIT OF ABIRATERONE ACETATE IN PATIENTS WITH CHEMOTHERAPY-NAÏVE METASTATIC CASTRATION-RESISTANT PROSTATE CANCER: RESULTS FROM COU-AA-302 Fred Saad, Thian Kheoh, Margaret K. Yu, Matthew R. Smith, Eric J. Small, Peter F.A. Mulders, Karim Fizazi, Dana Rathkopf, Stéphane Oudard, Howard I. Scher, Joaquim Bellmunt, Mary-Ellen Taplin, Ian D. Davis, Dirk Schrijvers, Andrew Protheroe, Arturo Molina, Thomas W. Griffin, Johann S. de Bono, and Charles J. Ryan Fred SaadFred Saad More articles by this author , Thian KheohThian Kheoh More articles by this author , Margaret K. YuMargaret K. Yu More articles by this author , Matthew R. SmithMatthew R. Smith More articles by this author , Eric J. SmallEric J. Small More articles by this author , Peter F.A. MuldersPeter F.A. Mulders More articles by this author , Karim FizaziKarim Fizazi More articles by this author , Dana RathkopfDana Rathkopf More articles by this author , Stéphane OudardStéphane Oudard More articles by this author , Howard I. ScherHoward I. Scher More articles by this author , Joaquim BellmuntJoaquim Bellmunt More articles by this author , Mary-Ellen TaplinMary-Ellen Taplin More articles by this author , Ian D. DavisIan D. Davis More articles by this author , Dirk SchrijversDirk Schrijvers More articles by this author , Andrew ProtheroeAndrew Protheroe More articles by this author , Arturo MolinaArturo Molina More articles by this author , Thomas W. GriffinThomas W. Griffin More articles by this author , Johann S. de BonoJohann S. de Bono More articles by this author , and Charles J. RyanCharles J. Ryan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.2210AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Abiraterone acetate (AA) is a prodrug of abiraterone, a selective androgen biosynthesis inhibitor that prolongs overall survival (OS) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) and is approved for use in this population. We conducted an exploratory analysis to determine the impact of prior endocrine therapy on clinical benefit of AA in chemotherapy-naïve pts with mCRPC in the randomized phase 3 study COU-AA-302. METHODS 1088 pts receiving mandatory continuous gonadotropin-releasing hormone [GnRH] agonists if not orchiectomized (96%) were randomized 1:1 to AA (1 g) + prednisone (P) (5 mg BID) or placebo + P. Radiographic progression-free survival (rPFS) and OS were co-primary end points. rPFS was defined as time to first occurrence of bone scan progression by Prostate Cancer Working Group 2 criteria, progression by computed tomography/magnetic resonance imaging by modified Response Evaluation Criteria in Solid Tumors 1.0, or death, whichever came first. We compared the treatment effect of AA on rPFS (investigator review at 55% of OS events) for subgroups above or below the median duration of prior endocrine therapy in 2 categories: prior GnRH agonists and androgen receptor (AR) inhibitors. Cox model was used to obtain the hazard ratio (HR) and associated 95% confidence interval (CI) with statistical inference by log rank statistic. RESULTS Most pts were exposed to prior GnRH agonists and AR inhibitors (Table). Irrespective of median duration of prior GnRH agonist or AR inhibitor therapy, rPFS was significantly more favorable with AA + P than placebo + P. Median rPFS was increased in pts with longer prior exposure to GnRH agonists or AR inhibitors as compared within both AA + P and placebo + P treatment groups. CONCLUSIONS Clinical benefit with AA + P vs placebo + P was demonstrated by significantly improved rPFS regardless of whether pts had exposure to prior endocrine therapy above or below the median duration of 37 and 16 months for GnRH agonists or AR inhibitors, respectively. Additional analyses are warranted to fully assess the impact of prior GnRH agonist and antiandrogen treatment duration. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e810 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Fred Saad More articles by this author Thian Kheoh More articles by this author Margaret K. Yu More articles by this author Matthew R. Smith More articles by this author Eric J. Small More articles by this author Peter F.A. Mulders More articles by this author Karim Fizazi More articles by this author Dana Rathkopf More articles by this author Stéphane Oudard More articles by this author Howard I. Scher More articles by this author Joaquim Bellmunt More articles by this author Mary-Ellen Taplin More articles by this author Ian D. Davis More articles by this author Dirk Schrijvers More articles by this author Andrew Protheroe More articles by this author Arturo Molina More articles by this author Thomas W. Griffin More articles by this author Johann S. de Bono More articles by this author Charles J. Ryan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...