PD34-06 SERUM TESTOSTERONE AS A PREDICTIVE BIOMARKER FOR PSA RESPONSE: RESULTS FROM A RANDOMISED TRIAL COMPARING ENZALUTAMIDE WITH ABIRATERONE ACETATE PLUS PREDNISONE

Abstract

You have accessJournal of UrologyProstate Cancer: Advanced (including Drug Therapy) III (PD34)1 Sep 2021PD34-06 SERUM TESTOSTERONE AS A PREDICTIVE BIOMARKER FOR PSA RESPONSE: RESULTS FROM A RANDOMISED TRIAL COMPARING ENZALUTAMIDE WITH ABIRATERONE ACETATE PLUS PREDNISONE Klara Kvorning Ternov, Jens Sønksen, Mikkel Fode, Henriette Lindberg, Rasmus Bisbjerg, Ganesh Palapattu, and Peter Busch Østergren Klara Kvorning TernovKlara Kvorning Ternov More articles by this author , Jens SønksenJens Sønksen More articles by this author , Mikkel FodeMikkel Fode More articles by this author , Henriette LindbergHenriette Lindberg More articles by this author , Rasmus BisbjergRasmus Bisbjerg More articles by this author , Ganesh PalapattuGanesh Palapattu More articles by this author , and Peter Busch ØstergrenPeter Busch Østergren More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002038.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Baseline serum testosterone has been suggested to be a predictive biomarker of patient important outcomes in men with metastatic castration-resistant prostate cancer (mCRPC). Herein, we investigate the prostate-specific antigen (PSA) treatment response based on baseline testosterone levels in men treated first-line with enzalutamide (ENZ) or abiraterone acetate plus prednisone (AAP) for mCRPC. METHODS: We randomised (1:1) men to ENZ (160 mg/day) or AAP (1000 mg abiraterone acetate and 10 mg prednisone/day) groups, in this investigator-initiated phase IV trial. Eligible patients had progressive metastatic prostate cancer despite castrate levels of testosterone (<1.7nmol/L). The purpose of this trial was to compare side-effects between ENZ and AAP. In this exploratory analysis, patients were grouped according to baseline testosterone levels above the mean or less than or equal to the mean. PSA progression-free survival (PFS) was analysed with Kaplan-Meier and with univariate and multivariable (including treatment, testosterone and PSA) cox regression analyses. PSA response rates (≥50% reduction in PSA) were compared between testosterone groups with Chi-Square test for the entire cohort and treatment subgroups. Serum testosterone was measured by the gold standard assay liquid chromatography–tandem mass spectrometry. RESULTS: 166 patients (82 treated with ENZ and 84 with AAP) were included in the analyses. The mean baseline testosterone was 0.35nmol/L (10ng/dL). Median follow-up was 22.3 months. Men with baseline testosterone above the mean value had longer PSA PFS (16.6 vs. 9.9 months, hazard ratio 0.59, 95% confidence interval 0.41; 0.85, p=0.005). No interaction was found between treatment subgroups in PSA PFS (p=0.635). The PSA response rate was greater in those with higher testosterone compared with those with lower testosterone overall (91% vs 74%, p=0.007). This difference was only statistically significant in the AAP treatment subgroup (table 1). CONCLUSIONS: Baseline serum testosterone seems to be predictive of PSA response in men with mCRPC treated with ENZ or AAP and may be useful for risk stratification of men with mCRPC. Source of Funding: Herlev and Gentofte Hospital, Herlev, Denmark © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e584-e585 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Klara Kvorning Ternov More articles by this author Jens Sønksen More articles by this author Mikkel Fode More articles by this author Henriette Lindberg More articles by this author Rasmus Bisbjerg More articles by this author Ganesh Palapattu More articles by this author Peter Busch Østergren More articles by this author Expand All Advertisement Loading ...