Prospective Evaluation of Clinical Outcomes Using a Multiplex Liquid Biopsy Targeting Diverse Resistance Mechanisms in Metastatic Prostate Cancer.

Abstract

PURPOSE:

Nearly all men with prostate cancer treated with androgen receptor (AR) signaling inhibitors (ARSIs) develop resistance via diverse mechanisms including constitutive activation of the AR pathway, driven by AR genomic structural alterations, expression of AR splice variants (AR-Vs), or loss of AR dependence and lineage plasticity termed neuroendocrine prostate cancer. Understanding these de novo acquired ARSI resistance mechanisms is critical for optimizing therapy.

MATERIALS AND METHODS:

A novel liquid biopsy technology was used to collect mRNA from circulating tumor cells (CTCs) to measure expression of AR-Vs, AR targets, and neuroendocrine prostate cancer markers. An institutional review board-approved prospective cohort (N = 99) was used to identify patterns of gene expression. Two prospective multicenter phase II clinical trials of ARSIs for men with castration-resistant prostate cancer (ClinicalTrials.gov: NCT01942837 [enzalutamide, N = 21] and NCT02025010 [abiraterone, N = 27]) were used to further validate these findings.

RESULTS:

Hierarchical clustering of CTC transcripts identified two distinct clusters. Cluster 2 (C2) exhibited increased expression of AR-regulated genes and was associated with worse overall survival (median 8.6 v 22.4 months; P < .01; hazard ratio [HR] = 3.45 [1.9 to 6.14]). In multivariable analysis, C2 was prognostic independent of other clinicopathologic variables. AR-V status was not significant when accounting for C2. Upon further validation in pooled multicenter phase II trials, C2 was associated with worse overall survival (15.2 months v not reached; P < .01; HR = 8.43 [2.74 to 25.92]), prostate-specific antigen progression-free survival (3.6 v 12 months; P < .01; HR = 4.64 [1.53 to 14.11]), and radiographic progression-free survival (2.7 v 40.6 months; P < .01; HR = 4.64 [1.82 to 17.41]).

CONCLUSION:

We demonstrate that a transcriptional profile detectable in CTCs obtained from liquid biopsies can serve as an independent prognostic marker beyond AR-V7 in patients with metastatic prostate cancer and can be used to identify the emergence of multiple ARSI resistance mechanisms. This is currently being investigated in additional prospective trials.

• Authors: Jamie M Sperger, Hamid Emamekhoo, Rana R McKay, Charlotte N Stahlfeld, Anupama Singh, Xinyi E Chen, Lucia Kwak, Cole S Gilsdorf, Serena K Wolfe, Xiao X Wei, Rebecca Silver, Zhenwei Zhang, Michael J Morris, Glenn Bubley, Felix Y Feng, Howard I Scher, Dana Rathkopf, Scott M Dehm, Toni K Choueiri, Susan Halabi, Andrew J Armstrong, Alexander W Wyatt, Mary-Ellen Taplin, Shuang G Zhao, Joshua M Lang
• Journal: Journal of clinical oncology : official journal of the American Society of Clinical Oncology (J Clin Oncol) Vol. 39 Issue 26 Pg. 2926-2937 (09 10 2021) ISSN: 1527-7755 [Electronic] United States
• PMID: 34197212 (Publication Type: Journal Article, Multicenter Study, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• AR protein, human
• Androgen Antagonists
• Androstenes
• Benzamides
• Biomarkers, Tumor
• Nitriles
• Receptors, Androgen
• Phenylthiohydantoin
• enzalutamide
• abiraterone

Topics

• Aged
• Aged, 80 and over
• Alternative Splicing
• Androgen Antagonists (therapeutic use)
• Androstenes (therapeutic use)
• Benzamides (therapeutic use)
• Biomarkers, Tumor (genetics)
• Clinical Decision-Making
• Clinical Trials, Phase II as Topic
• Drug Resistance, Neoplasm (genetics)
• Gene Expression Profiling
• Humans
• Liquid Biopsy
• Male
• Middle Aged
• Multiplex Polymerase Chain Reaction
• Neoplastic Cells, Circulating (metabolism, pathology)
• Nitriles (therapeutic use)
• Phenylthiohydantoin (therapeutic use)
• Predictive Value of Tests
• Progression-Free Survival
• Prospective Studies
• Prostatic Neoplasms (blood, drug therapy, genetics, pathology)
• Receptors, Androgen (genetics)
• Time Factors
• Transcriptome
• United States