Deep Prostate-specific Antigen Response following Addition of Apalutamide to Ongoing Androgen Deprivation Therapy and Long-term Clinical Benefit in SPARTAN

Fred Saad, Eric J. Small, Felix Y. Feng, Julie N. Graff, David Olmos, Boris A. Hadaschik, Stéphane Oudard, Anil Londhe, Amitabha Bhaumik, Angela Lopez-Gitlitz, Shibu Thomas, Suneel D. Mundle, Simon Chowdhury, Matthew R. Smith

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Background: Apalutamide plus androgen deprivation therapy (ADT) significantly improved metastasis-free survival (MFS), overall survival (OS), and time to prostate-specific antigen (PSA) progression in the placebo-controlled SPARTAN study of high-risk nonmetastatic castration-resistant prostate cancer (nmCRPC). Objective: To assess the relationships between PSA kinetics, outcomes, and molecular subtypes in SPARTAN. Design, setting, and participants: The authors conducted a post hoc analysis of nmCRPC patients randomized to receive apalutamide (n = 806) or placebo (n = 401) plus ADT and a subset stratified by molecular classifiers. Intervention: Apalutamide 240 mg/d. Outcome measurements and statistical analysis: The association between PSA kinetics and MFS, OS, time to PSA progression, and molecular subtypes was evaluated using the landmark analysis and Kaplan-Meier methods. Results and limitations: By 3 mo, PSA decreased in most apalutamide-treated patients and increased in most placebo-treated patients. After apalutamide, the median time to PSA nadir, confirmed ≥50% PSA reduction, ≥90% PSA reduction, and PSA ≤0.2 ng/ml were 7.4, 1.0, 1.9, and 2.8 mo, respectively. By 6 mo, 90%, 57%, and 32% of apalutamide patients had ≥50% PSA reduction, ≥90% PSA reduction, and PSA ≤0.2 ng/ml, respectively, while only 1.5% of placebo patients experienced ≥50% PSA reduction. PSA reductions were observed within 3 mo and up to 12 mo of apalutamide treatment, and were similar across molecular subtypes. Deep PSA responses (≥90% PSA reduction or PSA ≤0.2 ng/ml) at landmark 6-mo apalutamide treatment were significantly associated with improved time to PSA progression (hazard ratio {HR} [95% confidence interval {CI}] 0.25 [0.18–0.33] or 0.13 [0.08–0.21]), MFS (0.41 [0.29–0.57] or 0.3 [0.19–0.47]), and OS (0.45 [0.35–0.59] or 0.26 [0.18–0.38]; p < 0.001 for all). Conclusions: Apalutamide plus ADT produced rapid, deep, and durable PSA responses by 6-mo treatment regardless of assessed molecular prognostic markers. An early PSA response with apalutamide was associated with clinical benefits, supporting prognostic value of PSA monitoring. Patient summary: In this report, we describe how prostate-specific antigen (PSA) levels relate to outcomes in patients with nonmetastatic castration-resistant prostate cancer treated with apalutamide plus androgen deprivation therapy (ADT). We found that treatment with apalutamide plus ADT resulted in rapid, deep, and durable PSA responses in the majority of patients, including those with high-risk molecular subtypes, which were associated with improved survival.

Original languageEnglish (US)
Pages (from-to)184-192
Number of pages9
JournalEuropean Urology
Volume81
Issue number2
DOIs
StatePublished - Feb 2022

Keywords

  • Androgen antagonists
  • Nonmetastatic castration-resistant prostate cancer
  • Prostate-specific antigen kinetics
  • Prostatic neoplasm

ASJC Scopus subject areas

  • Urology

Fingerprint

Dive into the research topics of 'Deep Prostate-specific Antigen Response following Addition of Apalutamide to Ongoing Androgen Deprivation Therapy and Long-term Clinical Benefit in SPARTAN'. Together they form a unique fingerprint.

Cite this