Abiraterone acetate plus prednisone in non-metastatic biochemically recurrent castration-naïve prostate cancer

Eur J Cancer. 2021 Nov:157:259-267. doi: 10.1016/j.ejca.2021.06.017. Epub 2021 Sep 15.

Abstract

Background: Intermittent androgen deprivation therapy (ADT) in biochemically recurrent castration-naïve prostate cancer is non-inferior to continuous therapy. We hypothesised that finite-duration abiraterone acetate plus prednisone (Abi +P) added to ADT will further reduce the duration of treatment exposure by prolonging time to prostate-specific antigen (PSA) recurrence without impacting eugonad state recovery.

Methods: This phase II, randomised, open-label trial enrolled patients with rising PSA ≥ 0.2 ng/ml after radical prostatectomy and/or a PSA ≥ 1 following radiotherapy. Patients were randomised 1:1 to receive Abi (1 g PO daily) + P (5 mg PO daily) + ADT or ADT alone for 8 months. The primary end-point was PSA-free survival difference at 1 year following completion of therapy.

Results: Between February 2013 and July 2016, 200 patients were enrolled. Of 100 patients randomised to each arm, 99 in the Abi +P arm and 98 in the ADT arm were evaluable. Median follow-up was 64.4 months. Median PSA-free survival was 27.0 months for the Abi +P-treated group versus 19.9 months for the ADT-treated group (hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.47-0.87). The PSA-free survival at 1 year post-treatment completion was 98% for the Abi +P group and 88% for the ADT group. Median time to eugonad state was 13.1 months for the abiraterone-treated group and 12.8 months for the ADT-treated group. Median eugonad PSA-free survival was 12.5 months for the abiraterone-treated group versus 9.0 for the ADT-treated group (HR 0.72, 95% CI 0.53-0.98). There were no significant between-group differences in androgen deprivation-related adverse events.

Conclusions: In men with biochemically recurrent prostate cancer following definitive treatment of the primary, finite duration treatment with ADT and Abi +P results in a significantly longer PSA relapse-free interval than treatment with ADT alone.

Keywords: Abiraterone acetate; Androgen deprivation therapy; Biochemically recurrent prostate cancer; Hormone-naïve prostate cancer; PSA-free survival; Time to PSA relapse.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abiraterone Acetate / administration & dosage
  • Adult
  • Aged
  • Aged, 80 and over
  • Androgen Antagonists / administration & dosage
  • Antineoplastic Combined Chemotherapy Protocols / administration & dosage*
  • Chemoradiotherapy, Adjuvant / methods
  • Disease-Free Survival
  • Drug Administration Schedule
  • Follow-Up Studies
  • Humans
  • Kallikreins / blood*
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / blood
  • Neoplasm Recurrence, Local / diagnosis
  • Neoplasm Recurrence, Local / epidemiology
  • Neoplasm Recurrence, Local / therapy*
  • Prednisone / administration & dosage
  • Prostate-Specific Antigen / blood*
  • Prostatectomy*
  • Prostatic Neoplasms / blood
  • Prostatic Neoplasms / diagnosis
  • Prostatic Neoplasms / mortality
  • Prostatic Neoplasms / therapy*
  • Time Factors

Substances

  • Androgen Antagonists
  • KLK3 protein, human
  • Kallikreins
  • Prostate-Specific Antigen
  • Abiraterone Acetate
  • Prednisone