SWOG S0421: Phase III study of docetaxel (D) and atrasentan (A) versus docetaxel and placebo (P) for men with advanced castrate resistant prostate cancer (CRPC).

Media type: E-Article

Title: SWOG S0421: Phase III study of docetaxel (D) and atrasentan (A) versus docetaxel and placebo (P) for men with advanced castrate resistant prostate cancer (CRPC)

Contributor: Quinn, David I.; Tangen, Catherine M.; Hussain, Maha; Lara, Primo; Goldkorn, Amir; Garzotto, Mark; Mack, Philip C.; Carducci, Michael Anthony; Monk, J. P.; Twardowski, Przemyslaw; Van Veldhuizen, Peter J.; Agarwal, Neeraj; Higano, Celestia S.; Vogelzang, Nicholas J.; Thompson, Ian Murchie

imprint: American Society of Clinical Oncology (ASCO), 2012

Language: English

DOI: 10.1200/jco.2012.30.15_suppl.4511

ISSN: 0732-183X; 1527-7755

Keywords: Cancer Research ; Oncology

Origination:

Footnote:

Description: 4511 Background: The endothelin pathway has a mechanistic role in bone metastases (mets). Atrasentan (A), an endothelin receptor antagonist, has reported activity in CRPC. This trial tested the survival impact of A + docetaxel (D) vs. D+ placebo (P) in CRPC pts with bone mets. Methods: Eligible CRPC pts, stratified for progression type, baseline pain index (BPI), extraskeletal mets and bisphosphonate (BisP) use, were randomized 1:1 to D+A vs. D+P for 12 3-wk cycles. Non-progressors could continue blinded drug alone for 16 more wks. Co-primary endpoints: overall (OS) and progression-free survival (PFS). 930 pts were needed to detect a 25% increase in med OS with D+A (1-sided log-rank, α=0.025, 87% power). Results: 991/1,038 pts were eligible: med age 69, 16% non-white, 61% on BisP, 31% prior prostatectomy, 42% worst pain by BPI ≥ 4, 20% PSA only progression and 56% extraskeletal mets. Multivariate analysis of baseline prognostic factors predicting worse OS were: measurable or evaluable disease progression, high BPI and extraskeletal mets (all p<0.02). No differences in median OS, PFS, or response between arms. Toxicities were similar between arms. Most common toxicities were fatigue, dyspnea, neutropenia and anemia. Addition of A trended to worse OS in pts with visceral mets (HR=1.13 p=0.21) and better OS in those without: bone only (HR=0.86, p=0.20). 357 pts continued A or P up to 52 weeks, no OS difference was seen post-chemo for this subset (p=0.92). Conclusions: This phase III study found no benefit for the addition of A to D in CRPC. Unless specific biomarkers can stratify a population for benefit, endothelin modulators have limited future use in advanced CRPC. Further analyses will test putative surrogacy effects of PSA, serum bone markers and circulating tumor cell kinetics for OS. [Table: see text]

Access State: Open Access

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