Pd01-06 Prostate-Specific Antigen Dynamics From the Phase 3 Embark Trial: A Post Hoc Analysis

You have accessJournal of UrologyProstate Cancer: Advanced (including Drug Therapy) I (PD01)1 May 2024PD01-06 PROSTATE-SPECIFIC ANTIGEN DYNAMICS FROM THE PHASE 3 EMBARK TRIAL: A POST HOC ANALYSIS Stephen J. Freedland, Ugo De Giorgi, Martin Gleave, Jamal Tarazi, Yiyun Tang, Gabriel P. Haas, Matt Rosales, Fabian Zohren, and Neal D. Shore Stephen J. FreedlandStephen J. Freedland , Ugo De GiorgiUgo De Giorgi , Martin GleaveMartin Gleave , Jamal TaraziJamal Tarazi , Yiyun TangYiyun Tang , Gabriel P. HaasGabriel P. Haas , Matt RosalesMatt Rosales , Fabian ZohrenFabian Zohren , and Neal D. ShoreNeal D. Shore View All Author Informationhttps://doi.org/10.1097/01.JU.0001009540.33579.43.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: In the EMBARK trial, enzalutamide + leuprolide (enza combo) and enza monotherapy (mono) showed statistically superior and clinically meaningful improvements in metastasis-free survival (MFS) vs placebo + leuprolide (alone) while maintaining quality of life in patients (pts) with high-risk biochemically recurrent (BCR) prostate cancer. Importantly, EMBARK included a treatment (tx) suspension at week 37 if prostate-specific antigen (PSA) was<0.2 ng/mL and re-initiation once PSA rose to pre-defined thresholds. Here, a post hoc analysis of PSA dynamics in EMBARK is presented to understand the time course to undetectable PSA and likelihood of undetectable PSA after tx re-initiation. METHODS: EMBARK (NCT02319837) is a randomized, phase 3 study of pts with BCR after local therapy considered high-risk: PSA doubling time≤9 months and PSA≥2 ng/mL above nadir post-radiotherapy (RT) or≥1 ng/mL after radical prostatectomy (RP) ± postoperative RT. Pts were randomized (1:1:1) to enza combo 160 mg/day (double-blind), leuprolide alone (double-blind), or enza mono (open-label). Leuprolide 22.5 mg was administered every 12 weeks. If serum PSA was<0.2 ng/mL at week 36, tx was suspended at week 37 and restarted when PSA was≥2 ng/mL for pts with primary RP and≥5 ng/mL for pts without RP. A post hoc analysis of PSA dynamics in the intent-to-treat population was analyzed descriptively in each tx cohort. RESULTS: Of 1068 eligible and randomized pts, most pts in all 3 tx cohorts reached the first occurrence of undetectable PSA (<0.2 ng/mL) by week 25 (Table 1); percentages were higher for enza combo and mono vs leuprolide alone. More pts treated with enza combo and enza mono had tx suspended vs leuprolide alone. Of pts who suspended tx at week 37, 89% of pts re-initiated tx with enza mono, 85% of pts re-initiated tx with leuprolide alone, and 75% pts re-initiated tx with enza combo. Of pts who re-initiated tx, ∼90% of pts or more treated with enza combo or mono reached undetectable PSA vs 73% with leuprolide alone. CONCLUSIONS: In pts with high-risk BCR, more pts who were treated with enza combo and enza mono reached undetectable PSA, they reached undetectable PSA sooner, had tx suspended at week 37, and achieved undetectable PSA following tx re-initiation vs leuprolide alone. Source of Funding: Pfizer Inc. and Astellas Pharma Inc © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e65 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Stephen J. Freedland More articles by this author Ugo De Giorgi More articles by this author Martin Gleave More articles by this author Jamal Tarazi More articles by this author Yiyun Tang More articles by this author Gabriel P. Haas More articles by this author Matt Rosales More articles by this author Fabian Zohren More articles by this author Neal D. Shore More articles by this author Expand All Advertisement PDF downloadLoading ...