Randomized phase III study of enzalutamide compared with enzalutamide plus abiraterone for metastatic castration-resistant prostate cancer (Alliance A031201 trial) Journal Article


Authors: Morris, M. J.; Heller, G.; Hillman, D. W.; Bobek, O.; Ryan, C.; Antonarakis, E. S.; Bryce, A. H.; Hahn, O.; Beltran, H.; Armstrong, A. J.; Schwartz, L.; Lewis, L. D.; Beumer, J. H.; Langevin, B.; McGary, E. C.; Mehan, P. T.; Goldkorn, A.; Roth, B. J.; Xiao, H.; Watt, C.; Taplin, M. E.; Halabi, S.; Small, E. J.
Article Title: Randomized phase III study of enzalutamide compared with enzalutamide plus abiraterone for metastatic castration-resistant prostate cancer (Alliance A031201 trial)
Abstract: PURPOSEEnzalutamide and abiraterone both target androgen receptor signaling but via different mechanisms. The mechanism of action of one drug may counteract the resistance pathways of the other. We sought to determine whether the addition of abiraterone acetate and prednisone (AAP) to enzalutamide prolongs overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) in the first-line setting.PATIENTS AND METHODSMen with untreated mCRPC were randomly assigned (1:1) to receive first-line enzalutamide with or without AAP. The primary end point was OS. Toxicity, prostate-specific antigen declines, pharmacokinetics, and radiographic progression-free survival (rPFS) were also examined. Data were analyzed using an intent-to-treat approach. The Kaplan-Meier estimate and the stratified log-rank statistic were used to compare OS between treatments.RESULTSIn total, 1,311 patients were randomly assigned: 657 to enzalutamide and 654 to enzalutamide plus AAP. OS was not statistically different between the two arms (median, 32.7 [95% CI, 30.5 to 35.4] months for enzalutamide v 34.2 [95% CI, 31.4 to 37.3] months for enzalutamide and AAP; hazard ratio [HR], 0.89; one-sided P = .03; boundary nominal significance level = .02). rPFS was longer in the combination arm (median rPFS, 21.3 [95% CI, 19.4 to 22.9] months for enzalutamide v 24.3 [95% CI, 22.3 to 26.7] months for enzalutamide and AAP; HR, 0.86; two-sided P = .02). However, pharmacokinetic clearance of abiraterone was 2.2- to 2.9-fold higher when administered with enzalutamide, compared with clearance values for abiraterone alone.CONCLUSIONThe addition of AAP to enzalutamide for first-line treatment of mCRPC was not associated with a statistically significant benefit in OS. Drug-drug interactions between the two agents resulting in increased abiraterone clearance may partly account for this result, although these interactions did not prevent the combination regimen from having more nonhematologic toxicity. NCI study of enza/abi yields no advantage over enza for OS for mCRPC. Novel DDI findings might explain why.
Keywords: survival; design; recommendations; clinical-trials; combination; acetate
Journal Title: Journal of Clinical Oncology
Volume: 41
Issue: 18
ISSN: 0732-183X
Publisher: American Society of Clinical Oncology  
Date Published: 2023-06-20
Start Page: 3352
End Page: 3362
Language: English
ACCESSION: WOS:001025966400012
DOI: 10.1200/jco.22.02394
PROVIDER: wos
PMCID: PMC10414728
PUBMED: 36996380
Notes: The MSK Cancer Center Support Grant (P30 CA008748) is acknowledged in the PubMed record and PDF. Corresponding MSK author is Michael J. Morris -- Source: Wos
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MSK Authors
  1. Glenn Heller
    399 Heller
  2. Han Xiao
    61 Xiao
  3. Michael Morris
    582 Morris