Publications by authors named "Russell Z Szmulewitz"

42 Publications

A prospective clinical and transcriptomic feasibility study of oral-only hormonal therapy with radiation for unfavorable prostate cancer in men 70 years of age and older or with comorbidity.

Cancer 2021 Apr 21. Epub 2021 Apr 21.

Department of Radiation and Cellular Oncology, University of Chicago Medicine, Chicago, Illinois.

Background: Androgen deprivation therapy (ADT) improves outcomes in unfavorable-risk prostate cancer (PCa) treated with radiation therapy (RT). It was hypothesized that replacing luteinizing hormone-releasing hormone (LHRH) agonists with a 5-α-reductase inhibitor (5-ARI) would improve hormonal health-related quality of life (HRQOL) without differentially suppressing androgen-responsive (AR) gene expression.

Methods: Patients with localized unfavorable-risk PCa, aged ≥70 years or Charlson Comorbidity Index score ≥2 were treated with oral ADT (oADT), consisting of 4 months of bicalutamide, a 5-ARI, and RT at 78 Gy. The primary end point was Expanded Prostate Cancer Index Composite HRQOL at 6 months ≤30%, and improvement compared with a synchronous standard of care (SOC) cohort receiving 4 months of bicalutamide and long-term LHRH agonist with RT. RNA sequencing was performed from matched pre-/post-ADT prostate tumor biopsies in a subset of men. Differential gene and pathway expressional changes were examined using gene set enrichment.

Results: Between 2011 and 2018, 40 and 30 men were enrolled in the oADT and SOC cohorts, respectively. Median follow-up was 40 months. Those with ≤30% decline in hormonal HRQOL at 6 months was 97% (oADT) and 93% (SOC). The average 6-month hormonal decline was 1% (oADT) versus 12% (SOC; P = .04). The 4-year freedom from biochemical failure was 88% (oADT) versus 81% (SOC; P = .48). RNA sequencing (n = 9) showed similar numbers of downregulated and upregulated genes between the treatment groups (fold-change = 2; false-discovery rate-adjusted P ≤ .05). Both treatments comparably decreased the expression of 20 genes in canonical androgen receptor signaling.

Conclusions: For men with PCa undergoing RT, oral versus standard ADT may improve 6-month QOL and appears to have a similar impact on androgen-responsive gene expression.
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http://dx.doi.org/10.1002/cncr.33556DOI Listing
April 2021

Circulating Tumor Cell Chromosomal Instability and Neuroendocrine Phenotype by Immunomorphology and Poor Outcomes in Men with mCRPC Treated with Abiraterone or Enzalutamide.

Clin Cancer Res 2021 Apr 5. Epub 2021 Apr 5.

Department of Medicine, Duke Prostate and Urologic Cancer Center, Duke Cancer Institute, Duke University, Durham, North Carolina.

Purpose: While the detection of AR-V7 in circulating tumor cells (CTC) is associated with resistance to abiraterone or enzalutamide in men with metastatic castration-resistant prostate cancer (mCRPC), it only accounts for a minority of this resistance. Neuroendocrine (NE) differentiation or chromosomal instability (CIN) may be additional mechanisms that mediate resistance.

Experimental Design: PROPHECY was a multicenter prospective study of men with high-risk mCRPC starting abiraterone or enzalutamide. A secondary objective was to assess Epic CTC CIN and NE phenotypes before abiraterone or enzalutamide and at progression. The proportional hazards (PH) model was used to investigate the prognostic importance of CIN and NE in predicting progression-free survival and overall survival (OS) adjusting for CTC number (CellSearch), AR-V7, prior therapy, and clinical risk score. The PH model was utilized to validate this association of NE with OS in an external dataset of patients treated similarly at Memorial Sloan Kettering Cancer Center (MSKCC; New York, NY).

Results: We enrolled 118 men with mCRPC starting on abiraterone or enzalutamide; 107 were evaluable on the Epic platform. Of these, 36.4% and 8.4% were CIN positive and NE positive, respectively. CIN and NE were independently associated with worse OS [HR, 2.2; 95% confidence interval (CI), 1.2-4.0 and HR 3.8; 95% CI, 1.2-12.3, respectively] when treated with abiraterone/enzalutamide. The prognostic significance of NE positivity for worse OS was confirmed in the MSKCC dataset ( = 173; HR, 5.7; 95% CI, 2.6-12.7).

Conclusions: A high CIN and NE CTC phenotype is independently associated with worse survival in men with mCRPC treated with abiraterone/enzalutamide, warranting further prospective controlled predictive studies to inform treatment decisions.
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http://dx.doi.org/10.1158/1078-0432.CCR-20-3471DOI Listing
April 2021

The Abiraterone Dosing Chess Match With Johnson & Johnson-Back in Check.

JAMA Oncol 2021 Mar 4. Epub 2021 Mar 4.

Section of Hematology/Oncology, Department of Medicine, The University of Chicago, Chicago, Illinois.

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http://dx.doi.org/10.1001/jamaoncol.2020.8087DOI Listing
March 2021

TRANSFORMER: A Randomized Phase II Study Comparing Bipolar Androgen Therapy Versus Enzalutamide in Asymptomatic Men With Castration-Resistant Metastatic Prostate Cancer.

J Clin Oncol 2021 Apr 22;39(12):1371-1382. Epub 2021 Feb 22.

The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD.

Purpose: Prostate cancer (PCa) becomes resistant to androgen ablation through adaptive upregulation of the androgen receptor in response to the low-testosterone microenvironment. Bipolar androgen therapy (BAT), defined as rapid cycling between high and low serum testosterone, disrupts this adaptive regulation in castration-resistant PCa (CRPC).

Methods: The TRANSFORMER (Testosterone Revival Abolishes Negative Symptoms, Fosters Objective Response and Modulates Enzalutamide Resistance) study is a randomized study comparing monthly BAT (n = 94) with enzalutamide (n = 101). The primary end point was clinical or radiographic progression-free survival (PFS); crossover was permitted at progression. Secondary end points included overall survival (OS), prostate-specific antigen (PSA) and objective response rates, PFS from randomization through crossover (PFS2), safety, and quality of life (QoL).

Results: The PFS was 5.7 months for both arms (hazard ratio [HR], 1.14; 95% CI, 0.83 to 1.55; = .42). For BAT, 50% decline in PSA (PSA50) was 28.2% of patients versus 25.3% for enzalutamide. At crossover, PSA50 response occurred in 77.8% of patients crossing to enzalutamide and 23.4% to BAT. The PSA-PFS for enzalutamide increased from 3.8 months after abiraterone to 10.9 months after BAT. The PFS2 for BAT→enzalutamide was 28.2 versus 19.6 months for enzalutamide→BAT (HR, 0.44; 95% CI, 0.22 to 0.88; = .02). OS was 32.9 months for BAT versus 29.0 months for enzalutamide (HR, 0.95; 95% CI, 0.66 to 1.39; = .80). OS was 37.1 months for patients crossing from BAT to enzalutamide versus 30.2 months for the opposite sequence (HR, 0.68; 95% CI, 0.36 to 1.28; = .225). BAT adverse events were primarily grade 1-2. Patient-reported QoL consistently favored BAT.

Conclusion: This randomized trial establishes meaningful clinical activity and safety of BAT and supports additional study to determine its optimal clinical integration. BAT can sensitize CRPC to subsequent antiandrogen therapy. Further study is required to confirm whether sequential therapy with BAT and enzalutamide can improve survival in men with CRPC.
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http://dx.doi.org/10.1200/JCO.20.02759DOI Listing
April 2021

Efficacy of Enzalutamide plus Androgen Deprivation Therapy in Metastatic Hormone-Sensitive Prostate Cancer by Pattern of Metastatic Spread: ARCHES Post Hoc Analyses.

J Urol 2021 May 28;205(5):1361-1371. Epub 2020 Dec 28.

University Hospital, Eberhard Karls University of Tübingen, Tübingen, Germany.

Purpose: Enzalutamide plus androgen deprivation therapy has previously been shown to improve clinical outcomes in men with metastatic hormone-sensitive prostate cancer (ARCHES; NCT02677896). Here, we assessed if and how the pattern of metastatic spread impacts efficacy of enzalutamide plus androgen deprivation therapy in men enrolled in ARCHES.

Materials And Methods: Men with metastatic hormone-sensitive prostate cancer were randomized 1:1 to enzalutamide (160 mg/day) plus androgen deprivation therapy or placebo plus androgen deprivation therapy, stratified by disease volume and prior docetaxel treatment. The primary end point was radiographic progression-free survival. Secondary end points included time to prostate specific antigen progression, initiation of new antineoplastic therapy, first symptomatic skeletal event and castration resistance. Post hoc analyses were performed by pattern of metastatic spread based on study entry imaging.

Results: Of the overall population with metastases identified at enrollment (1,146), the largest patient subgroups were those with bone metastases only (513) and those with bone plus lymph node metastases (351); there were fewer men with lymph node metastases only (154) and men with visceral±bone or lymph node metastases (128). Enzalutamide plus androgen deprivation therapy reduced the risk of radiographic progression vs placebo plus androgen deprivation therapy in men with bone metastases only (HR 0.33) and bone plus lymph node metastases (HR 0.31). Similar improvements in secondary end points were also observed in these subgroups.

Conclusions: These findings indicate that treatment with enzalutamide plus androgen deprivation therapy provides improvements in men with bone and/or lymph node metastases but may be less effective in men with visceral patterns of spread.
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http://dx.doi.org/10.1097/JU.0000000000001568DOI Listing
May 2021

Prospective Multicenter Study of Circulating Tumor Cell AR-V7 and Taxane Versus Hormonal Treatment Outcomes in Metastatic Castration-Resistant Prostate Cancer.

JCO Precis Oncol 2020 28;4. Epub 2020 Oct 28.

Department of Biostatistics and Bioinforamtics, Duke University, Durham, NC.

Purpose: Androgen receptor splice variant 7 (AR-V7) detection in circulating tumor cells (CTCs) is associated with a low probability of response and short progression-free (PFS) and overall survival (OS) in men with metastatic castration-resistant prostate cancer (mCRPC) treated with enzalutamide or abiraterone. However, it is unclear whether such men benefit from taxane chemotherapy.

Patients And Methods: PROPHECY is a multicenter prospective blinded study of patients with poor-risk mCRPC starting abiraterone or enzalutamide and observed through subsequent progression and taxane chemotherapy. We assessed AR-V7 status using the Johns Hopkins modified AdnaTest CTC AR-V7 messenger RNA assay and the Epic Sciences CTC nuclear-localized AR-V7 protein assay before treatment. The primary objective was to validate the independent prognostic value of CTC AR-V7 status based on radiographic/clinical PFS. OS, confirmed prostate-specific antigen (PSA), and objective radiologic responses were secondary end points.

Results: We enrolled 118 men with mCRPC treated with abiraterone or enzalutamide, 51 of whom received subsequent docetaxel or cabazitaxel. Pretreatment CTC AR-V7 status by the Johns Hopkins and Epic Sciences assays was independently associated with worse PFS (hazard ratio [HR], 1.7; 95% CI, 1.0 to 2.9 and HR, 2.1; 95% CI, 1.0 to 4.4, respectively) and OS (HR, 3.3; 95% CI, 1.7 to 6.3 and HR, 3.0; 95% CI, 1.4 to 6.3, respectively) and a low probability of confirmed PSA responses, ranging from 0% to 11%, during treatment with abiraterone or enzalutamide. At progression, subsequent CTC AR-V7 detection was not associated with an inferior PSA or radiographic response or worse PFS or OS with subsequent taxane chemotherapy after adjusting for CellSearch CTC enumeration and clinical prognostic factors.

Conclusion: Detection of AR-V7 in CTCs by two different blood-based assays is independently associated with shorter PFS and OS with abiraterone or enzalutamide, but such men with AR-V7-positive disease still experience clinical benefits from taxane chemotherapy.
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http://dx.doi.org/10.1200/PO.20.00200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608579PMC
October 2020

Cancer and Leukemia Group B 90203 (Alliance): Radical Prostatectomy With or Without Neoadjuvant Chemohormonal Therapy in Localized, High-Risk Prostate Cancer.

J Clin Oncol 2020 09 24;38(26):3042-3050. Epub 2020 Jul 24.

Memorial Sloan Kettering Cancer Center, New York, NY.

Purpose: Radical prostatectomy (RP) alone is often inadequate in curing men with clinically localized, high-risk prostate cancer (PC). We hypothesized that chemohormonal therapy (CHT) with androgen-deprivation therapy plus docetaxel before RP would improve biochemical progression-free survival (BPFS) over RP alone.

Patients And Methods: Men with clinically localized, high-risk PC were assigned to RP alone or neoadjuvant CHT with androgen deprivation plus docetaxel (75 mg/m body surface area every 3 weeks for 6 cycles) and RP. The primary end point was 3-year BPFS. Biochemical failure was defined as a serum prostate-specific antigen level > 0.2 ng/mL that increased on 2 consecutive occasions that were at least 3 months apart. Secondary end points included 5-year BPFS, overall BPFS, local recurrence, metastasis-free survival (MFS), PC-specific mortality, and overall survival (OS).

Results: In total, 788 men were randomly assigned. Median follow-up time was 6.1 years. The overall rates of grade 3 and 4 adverse events during chemotherapy were 26% and 19%, respectively. No difference was seen in 3-year BPFS between neoadjuvant CHT plus RP and RP alone (0.89 0.84, respectively; 95% CI for the difference, -0.01 to 0.11; = .11). Neoadjuvant CHT was associated with improved overall BPFS (hazard ratio [HR], 0.69; 95% CI, 0.48 to 0.99), improved MFS (HR, 0.70; 95% CI, 0.51 to 0.95), and improved OS (HR, 0.61; 95% CI, 0.40 to 0.94) compared with RP alone.

Conclusion: The primary study end point, 3-year BPFS, was not met. Although some improvement was seen in secondary end points, any potential benefit must be weighed against toxicity. Our data do not support the routine use of neoadjuvant CHT and RP in patients with clinically localized, high-risk PC at this time.
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http://dx.doi.org/10.1200/JCO.20.00315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7479762PMC
September 2020

Slow-, Tight-Binding Inhibition of CYP17A1 by Abiraterone Redefines Its Kinetic Selectivity and Dosing Regimen.

J Pharmacol Exp Ther 2020 09 17;374(3):438-451. Epub 2020 Jun 17.

Department of Pharmacy, Faculty of Science (E.J.Y.C., R.W.Y.N., H.T.T., C.L.L.C., E.C.Y.C.) and Department of Biological Sciences (H.F.), National University of Singapore, Singapore, Singapore; Department of Clinical Pharmacology and Flinders Centre for Innovation in Cancer, College of Medicine and Public Health, Flinders University, Adelaide, Australia (P.C.N., J.O.M.); Bioinformatics Institute, Biotransformation Innovation Platform (BioTrans) (F.L.) and Bioinformatics Institute (H.F.), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore; Department of Surgery, National University Health System, Singapore, Singapore (E.C., K.E.); Department of Urology, National University Hospital, Singapore, Singapore (E.C., K.E.); Centre for Computational Biology, DUKE-NUS Medical School, Singapore, Singapore (H.F.); The University of Chicago, Chicago, Illinois (R.Z.S.); National Cancer Institute, Rockville, Maryland (C.J.P., W.D.F.); and National University Cancer Institute, Singapore (NCIS), NUH Medical Centre (NUHMC), Singapore, Singapore (E.C.Y.C.)

Substantial evidence underscores the clinical efficacy of inhibiting CYP17A1-mediated androgen biosynthesis by abiraterone for treatment of prostate oncology. Previous structural analysis and in vitro assays revealed inconsistencies surrounding the nature and potency of CYP17A1 inhibition by abiraterone. Here, we establish that abiraterone is a slow-, tight-binding inhibitor of CYP17A1, with initial weak binding preceding the subsequent slow isomerization to a high-affinity CYP17A1-abiraterone complex. The in vitro inhibition constant of the final high-affinity CYP17A1-abiraterone complex ( )yielded a binding free energy of -12.8 kcal/mol that was quantitatively consistent with the in silico prediction of -14.5 kcal/mol. Prolonged suppression of dehydroepiandrosterone (DHEA) concentrations observed in VCaP cells after abiraterone washout corroborated its protracted CYP17A1 engagement. Molecular dynamics simulations illuminated potential structural determinants underlying the rapid reversible binding characterizing the two-step induced-fit model. Given the extended residence time (42 hours) of abiraterone within the CYP17A1 active site, in silico simulations demonstrated sustained target engagement even when most abiraterone has been eliminated systemically. Subsequent pharmacokinetic-pharmacodynamic (PK-PD) modeling linking time-dependent CYP17A1 occupancy to in vitro steroidogenic dynamics predicted comparable suppression of downstream DHEA-sulfate at both 1000- and 500-mg doses of abiraterone acetate. This enabled mechanistic rationalization of a clinically reported PK-PD disconnect, in which equipotent reduction of downstream plasma DHEA-sulfate levels was achieved despite a lower systemic exposure of abiraterone. Our novel findings provide the impetus for re-evaluating the current dosing paradigm of abiraterone with the aim of preserving PD efficacy while mitigating its dose-dependent adverse effects and financial burden. SIGNIFICANCE STATEMENT: With the advent of novel molecularly targeted anticancer modalities, it is becoming increasingly evident that optimal dose selection must necessarily be predicated on mechanistic characterization of the relationships between target exposure, drug-target interactions, and pharmacodynamic endpoints. Nevertheless, efficacy has always been perceived as being exclusively synonymous with affinity-based measurements of drug-target binding. This work demonstrates how elucidating the slow-, tight-binding inhibition of CYP17A1 by abiraterone via in vitro and in silico analyses was pivotal in establishing the role of kinetic selectivity in mediating time-dependent CYP17A1 engagement and eventually downstream efficacy outcomes.
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http://dx.doi.org/10.1124/jpet.120.265868DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469252PMC
September 2020

Effect of Enzalutamide plus Androgen Deprivation Therapy on Health-related Quality of Life in Patients with Metastatic Hormone-sensitive Prostate Cancer: An Analysis of the ARCHES Randomised, Placebo-controlled, Phase 3 Study.

Eur Urol 2020 10 23;78(4):603-614. Epub 2020 Apr 23.

Duke Cancer Institute Center for Prostate and Urologic Cancer, Durham, NC, USA.

Background: In the ARCHES study in metastatic hormone-sensitive prostate cancer (mHSPC), enzalutamide plus androgen deprivation therapy (ADT) improved radiographic progression-free survival (rPFS) versus ADT alone.

Objective: To evaluate patient-reported outcomes (PROs) to week 73.

Design, Setting, And Participants: ARCHES (NCT02677896) was a randomised, double-blind, placebo-controlled, phase 3 study in mHSPC patients.

Intervention: Enzalutamide (160 mg/day) plus ADT or placebo plus ADT.

Outcome Measurements And Statistical Analysis: PROs were assessed at baseline, week 13, and every 12 wk until disease progression using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Prostate 25 (QLQ-PR25), Functional Assessment of Cancer Therapy-Prostate (FACT-P), Brief Pain Inventory Short Form, and EuroQoL 5-Dimensions, 5-Levels (EQ-5D-5 L) instruments. Endpoints included time to first (TTFD) and first confirmed (TTFCD) clinically meaningful deterioration (using predefined questionnaire thresholds) in health-related quality of life (HRQoL) and pain.

Results And Limitations: A total of 1150 patients received ADT plus enzalutamide (n = 574) or placebo (n = 576). Baseline PRO scores indicated high HRQoL and low pain, which was generally maintained in both groups. There were no statistically significant (nominal p > 0.05) between-group differences that occurred in both TTFD and TTFCD together for QLQ-PR25 and FACT-P scores. Enzalutamide significantly delayed TTFD in worst pain (by ∼3 mo; nominal p = 0.032), pain severity (nominal p = 0.021), and EQ-5D-5 L visual analogue scale score (nominal p = 0.0070) versus placebo (not significant for confirmed deterioration for pain outcomes). Enzalutamide delays deterioration in several HRQoL subscales and pain severity in high-volume disease.

Conclusions: Enzalutamide plus ADT enables men with mHSPC to maintain high-functioning HRQoL and low symptom burden.

Patient Summary: This study examined the effect on health-related quality of life and pain of adding enzalutamide or placebo to androgen deprivation therapy for patients with metastatic hormone-sensitive prostate cancer. Addition of enzalutamide allowed patients to maintain their health-related quality of life.
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http://dx.doi.org/10.1016/j.eururo.2020.03.019DOI Listing
October 2020

Phase I Study of DSTP3086S, an Antibody-Drug Conjugate Targeting Six-Transmembrane Epithelial Antigen of Prostate 1, in Metastatic Castration-Resistant Prostate Cancer.

J Clin Oncol 2019 12 5;37(36):3518-3527. Epub 2019 Nov 5.

Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, NY.

Purpose: Six-transmembrane epithelial antigen of the prostate 1 (STEAP1) is highly expressed in prostate cancers. DSTP3086S is a humanized immunoglobulin G1 anti-STEAP1 monoclonal antibody linked to the potent antimitotic agent monomethyl auristatin E. This study evaluated the safety and activity of DSTP3086S in patients with metastatic castration-resistant prostate cancer.

Methods: Patients were enrolled in a 3 + 3 dose escalation study to evaluate DSTP3086S (0.3 to 2.8 mg/kg intravenously) given once every 3 weeks followed by cohort expansion at the recommended phase II dose or weekly (0.8 to 1.0 mg/kg).

Results: Seventy-seven patients were given DSTP3086S once every 3 weeks, and seven were treated weekly. Two patients in the once-every-3-weeks dose escalation had dose-limiting grade 3 transaminitis. Grade 3 hyperglycemia and grade 4 hypophosphatemia were dose-limiting toxicities in one patient treated at 1.0 mg/kg weekly. Initial cohort expansion evaluated dosing at 2.8 mg/kg once every 3 weeks (n = 10), but frequent dose reductions led to testing of 2.4 mg/kg (n = 39) in the expansion phase. Common related adverse events (> 20%) across doses (once every 3 weeks) were fatigue, peripheral neuropathy, nausea, constipation, anorexia, diarrhea, and vomiting. DSTP3086S pharmacokinetics were linear. Among 62 patients who received > 2 mg/kg DSTP3086S once every 3 weeks, 11 (18%) demonstrated a ≥ 50% decline in prostate-specific antigen; two (6%) of 36 with measurable disease at baseline achieved a radiographic partial response; and of 27 patients with informative unfavorable baseline circulating tumor cells ≥ 5/7.5 mL of blood, 16 (59%) showed conversions to favorable circulating tumor cells < 5. No prostate-specific antigen or RECIST responses were seen with weekly dosing.

Conclusion: DSTP3086S has acceptable safety at the recommended phase II dose level of 2.4 mg/kg once every 3 weeks. Antitumor activity at doses between 2.25 and 2.8 mg/kg once every 3 weeks supports the potential benefit of treating STEAP1-expressing metastatic castration-resistant prostate cancer with an STEAP1-targeting antibody-drug conjugate.
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http://dx.doi.org/10.1200/JCO.19.00646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7351321PMC
December 2019

ARCHES: A Randomized, Phase III Study of Androgen Deprivation Therapy With Enzalutamide or Placebo in Men With Metastatic Hormone-Sensitive Prostate Cancer.

J Clin Oncol 2019 11 22;37(32):2974-2986. Epub 2019 Jul 22.

Eberhard Karls University of Tübingen, Tübingen, Germany.

Purpose: Enzalutamide, a potent androgen-receptor inhibitor, has demonstrated significant benefits in metastatic and nonmetastatic castration-resistant prostate cancer. We evaluated the efficacy and safety of enzalutamide in metastatic hormone-sensitive prostate cancer (mHSPC).

Methods: ARCHES (ClinicalTrials.gov identifier: NCT02677896) is a multinational, double-blind, phase III trial, wherein 1,150 men with mHSPC were randomly assigned 1:1 to enzalutamide (160 mg/day) or placebo, plus androgen deprivation therapy (ADT), stratified by disease volume and prior docetaxel chemotherapy. The primary end point was radiographic progression-free survival.

Results: As of October 14, 2018, the risk of radiographic progression or death was significantly reduced with enzalutamide plus ADT versus placebo plus ADT (hazard ratio, 0.39; 95% CI, 0.30 to 0.50; < .001; median not reached 19.0 months). Similar significant improvements in radiographic progression-free survival were reported in prespecified subgroups on the basis of disease volume and prior docetaxel therapy. Enzalutamide plus ADT significantly reduced the risk of prostate-specific antigen progression, initiation of new antineoplastic therapy, first symptomatic skeletal event, castration resistance, and reduced risk of pain progression. More men achieved an undetectable prostate-specific antigen level and/or an objective response with enzalutamide plus ADT ( < .001). Patients in both treatment groups reported a high baseline level of quality of life, which was maintained over time. Grade 3 or greater adverse events were reported in 24.3% of patients who received enzalutamide plus ADT versus 25.6% of patients who received placebo plus ADT, with no unexpected adverse events.

Conclusion: Enzalutamide with ADT significantly reduced the risk of metastatic progression or death over time versus placebo plus ADT in men with mHSPC, including those with low-volume disease and/or prior docetaxel, with a safety analysis that seems consistent with the safety profile of enzalutamide in previous clinical trials in castration-resistant prostate cancer.
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http://dx.doi.org/10.1200/JCO.19.00799DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6839905PMC
November 2019

Prospective Multicenter Validation of Androgen Receptor Splice Variant 7 and Hormone Therapy Resistance in High-Risk Castration-Resistant Prostate Cancer: The PROPHECY Study.

J Clin Oncol 2019 05 13;37(13):1120-1129. Epub 2019 Mar 13.

1 Duke University, Durham, NC.

Purpose: Androgen receptor splice variant 7 (AR-V7) results in a truncated receptor, which leads to ligand-independent constitutive activation that is not inhibited by anti-androgen therapies, including abiraterone or enzalutamide. Given that previous reports suggested that circulating tumor cell (CTC) AR-V7 detection is a poor prognostic indicator for the clinical efficacy of secondary hormone therapies, we conducted a prospective multicenter validation study.

Patients And Methods: PROPHECY ( ClinicalTrials.gov identifier: NCT02269982) is a multicenter, prospective-blinded study of men with high-risk mCRPC starting abiraterone acetate or enzalutamide treatment. The primary objective was to validate the prognostic significance of baseline CTC AR-V7 on the basis of radiographic or clinical progression free-survival (PFS) by using the Johns Hopkins University modified-AdnaTest CTC AR-V7 mRNA assay and the Epic Sciences CTC nuclear-specific AR-V7 protein assay. Overall survival (OS) and prostate-specific antigen responses were secondary end points.

Results: We enrolled 118 men with mCRPC who were starting abiraterone or enzalutamide treatment. AR-V7 detection by both the Johns Hopkins and Epic AR-V7 assays was independently associated with shorter PFS (hazard ratio, 1.9 [95% CI, 1.1 to 3.3; = .032] and 2.4 [95% CI, 1.1 to 5.1; = .020], respectively) and OS (hazard ratio, 4.2 [95% CI, 2.1 to 8.5] and 3.5 [95% CI, 1.6 to 8.1], respectively) after adjusting for CTC number and clinical prognostic factors. Men with AR-V7-positive mCRPC had fewer confirmed prostate-specific antigen responses (0% to 11%) or soft tissue responses (0% to 6%). The observed percentage agreement between the two AR-V7 assays was 82%.

Conclusion: Detection of AR-V7 in CTCs by two blood-based assays is independently associated with shorter PFS and OS with abiraterone or enzalutamide, and such men with mCRPC should be offered alternative treatments.
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http://dx.doi.org/10.1200/JCO.18.01731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494355PMC
May 2019

Safety and Efficacy of Hypofractionated Radiotherapy With Capecitabine in Elderly Patients With Urothelial Carcinoma.

Clin Genitourin Cancer 2019 Feb 12;17(1):e12-e18. Epub 2018 Oct 12.

Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL. Electronic address:

Background: Bladder cancer is commonly diagnosed in patients ineligible for radical cystectomy or chemoradiotherapy (chemo-RT) with cisplatin or fluorouracil with mitomycin. We assessed tolerability, efficacy, and toxicity of hypofractionated radiotherapy with capecitabine in this challenging population.

Patients And Methods: Patients with high-grade urothelial bladder cancer ineligible for radical cystectomy or high-intensity chemo-RT underwent maximal transurethral resection of bladder tumor followed by capecitabine (median, 825 mg/m per day 2 times a day) and radiation (median, 55 Gy in 2.2 Gy per fraction). Patients underwent surveillance cystoscopy and imaging, and were evaluated for toxicity, freedom from local failure and freedom from distant metastasis, progression-free survival, and overall survival.

Results: Eleven patients (median age, 80 years) with localized disease (n = 7), locally advanced disease (n = 3), or local-only recurrence after cystectomy (n = 1) were treated. Four patients (35%) had an Eastern Cooperative Oncology Group performance status of 2; median Charlson comorbidity index was 5. There was 1 acute grade 3 genitourinary event (9%), 6 acute grade 3 hematologic events (55%) of lymphopenia, and no acute grade 4 or higher events or hospitalizations. Ten patients (91%) completed radiotherapy, while 4 patients (36%) temporarily discontinued capecitabine. The complete response rate in the bladder was 64%. Two patients (18%) experienced late grade 1/2 genitourinary toxicities, and 1 (9%) experienced a transient late grade 4 genitourinary toxicity. With a median follow-up of 16.6 months, overall survival, progression-free survival, freedom from local failure, and freedom from distant metastasis at 1 year were 82%, 55%, 100%, and 55%, respectively, and at 2 years were 61%, 41%, 80%, and 55%, respectively.

Conclusion: Hypofractionated chemo-RT was well tolerated and was associated with a high rate of local control in this comorbid population, thus providing a treatment option for select bladder cancer patients.
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http://dx.doi.org/10.1016/j.clgc.2018.10.003DOI Listing
February 2019

A Phase II Trial of the Aurora Kinase A Inhibitor Alisertib for Patients with Castration-resistant and Neuroendocrine Prostate Cancer: Efficacy and Biomarkers.

Clin Cancer Res 2019 01 19;25(1):43-51. Epub 2018 Sep 19.

Department of Medicine, Weill Cornell Medicine, New York, New York.

Purpose: Neuroendocrine prostate cancer (NEPC) is an aggressive variant of prostate cancer that may develop or as a mechanism of treatment resistance. N-myc is capable of driving NEPC progression. Alisertib inhibits the interaction between N-myc and its stabilizing factor Aurora-A, inhibiting N-myc signaling, and suppressing tumor growth.

Patients And Methods: Sixty men were treated with alisertib 50 mg twice daily for 7 days every 21 days. Eligibility included metastatic prostate cancer and at least one: small-cell neuroendocrine morphology; ≥50% neuroendocrine marker expression; new liver metastases without PSA progression; or elevated serum neuroendocrine markers. The primary endpoint was 6-month radiographic progression-free survival (rPFS). Pretreatment biopsies were evaluated by whole exome and RNA-seq and patient-derived organoids were developed.

Results: Median PSA was 1.13 ng/mL (0.01-514.2), number of prior therapies was 3, and 68% had visceral metastases. Genomic alterations involved (55%), (46%), (29%), (29%), and (27%), and there was a range of androgen receptor signaling and NEPC marker expression. Six-month rPFS was 13.4% and median overall survival was 9.5 months (7.3-13). Exceptional responders were identified, including complete resolution of liver metastases and prolonged stable disease, with tumors suggestive of N-myc and Aurora-A overactivity. Patient organoids exhibited concordant responses to alisertib and allowed for the dynamic testing of Aurora-N-myc complex disruption.

Conclusions: Although the study did not meet its primary endpoint, a subset of patients with advanced prostate cancer and molecular features supporting Aurora-A and N-myc activation achieved significant clinical benefit from single-agent alisertib.
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http://dx.doi.org/10.1158/1078-0432.CCR-18-1912DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6320304PMC
January 2019

Low-Dose Abiraterone With Food: Rebutting an Editorial.

J Clin Oncol 2018 10 6;36(30):3060-3061. Epub 2018 Sep 6.

Russell Z. Szmulewitz, Theodore Karrison, Walter M. Stadler, and Mark J. Ratain, The University of Chicago, Chicago, IL.

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http://dx.doi.org/10.1200/JCO.2018.79.3018DOI Listing
October 2018

Reply to I.F. Tannock, P. Isaacsson Velho et al, M. Tiako Meyo et al, and F.J.S.H. Woei-A-Jin et al.

J Clin Oncol 2018 10 6;36(30):3064-3065. Epub 2018 Sep 6.

Russell Z. Szmulewitz, Walter M. Stadler, and Mark J. Ratain, The University of Chicago, Chicago, IL.

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http://dx.doi.org/10.1200/JCO.2018.79.3190DOI Listing
October 2018

MEIS1 and MEIS2 Expression and Prostate Cancer Progression: A Role For HOXB13 Binding Partners in Metastatic Disease.

Clin Cancer Res 2018 08 1;24(15):3668-3680. Epub 2018 May 1.

The Committee on Cancer Biology, The University of Chicago, Chicago, Illinois.

Germline mutations within the MEIS-interaction domain of HOXB13 have implicated a critical function for MEIS-HOX interactions in prostate cancer etiology and progression. The functional and predictive role of changes in MEIS expression within prostate tumor progression, however, remain largely unexplored. Here we utilize RNA expression datasets, annotated tissue microarrays, and cell-based functional assays to investigate the role of MEIS1 and MEIS2 in prostate cancer and metastatic progression. These analyses demonstrate a stepwise decrease in the expression of both MEIS1 and MEIS2 from benign epithelia, to primary tumor, to metastatic tissues. Positive expression of MEIS proteins in primary tumors, however, is associated with a lower hazard of clinical metastasis (HR = 0.28) after multivariable analysis. Pathway and gene set enrichment analyses identified MEIS-associated networks involved in cMYC signaling, cellular proliferation, motility, and local tumor environment. Depletion of MEIS1 and MEIS2 resulted in increased tumor growth over time , and decreased MEIS expression in both patient-derived tumors and MEIS-depleted cell lines was associated with increased expression of the protumorigenic genes cMYC and CD142, and decreased expression of AXIN2, FN1, ROCK1, SERPINE2, SNAI2, and TGFβ2. These data implicate a functional role for MEIS proteins in regulating cancer progression, and support a hypothesis whereby tumor expression of MEIS1 and MEIS2 expression confers a more indolent prostate cancer phenotype, with a decreased propensity for metastatic progression. .
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http://dx.doi.org/10.1158/1078-0432.CCR-17-3673DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6082699PMC
August 2018

Prospective International Randomized Phase II Study of Low-Dose Abiraterone With Food Versus Standard Dose Abiraterone In Castration-Resistant Prostate Cancer.

J Clin Oncol 2018 05 28;36(14):1389-1395. Epub 2018 Mar 28.

Russell Z. Szmulewitz, Abiola Ibraheem, Elia Martinez, Mark F. Kozloff, Chadi Nabhan, Theodore Karrison, Walter M. Stadler, and Mark J. Ratain, The University of Chicago, Chicago; Mark F. Kozloff, Ingalls Hospital, Harvey; Paul Fishkin, Illinois Cancer Care, Peoria, IL; Cody J. Peer and William D. Figg, National Cancer Institute, Rockville, MD; Bradley Carthon and R. Donald Harvey, Winship Cancer Institute of Emory University, Atlanta, GA; and Wei Peng Yong and Edmund Chiong, National University Cancer Institute, Singapore, Singapore.

Purpose Abiraterone acetate (AA) is a standard of care for metastatic castration-resistant prostate cancer (CRPC). Despite a large food effect, AA was administered under fasting conditions in its pivotal trials. We sought to test the hypothesis that low-dose AA (LOW; 250 mg with a low-fat meal) would have comparable activity to standard AA (STD; 1,000 mg fasting) in patients with CRPC. Patients and Methods Patients (n = 72) with progressive CRPC from seven institutions in the United States and Singapore were randomly assigned to STD or LOW. Both arms received prednisone 5 mg twice daily. Prostate-specific antigen (PSA) was assessed monthly, and testosterone/dehydroepiandrosterone sulfate were assessed every 12 weeks with disease burden radiographic assessments. Plasma was collected for drug concentrations. Log change in PSA, as a pharmacodynamic biomarker for efficacy, was the primary end point, using a noninferiority design. Progression-free survival (PFS), PSA response (≥ 50% reduction), change in androgen levels, and pharmacokinetics were secondary end points. Results Thirty-six patients were accrued to both arms. At 12 weeks, there was a greater effect on PSA in the LOW arm (mean log change, -1.59) compared with STD (-1.19), and noninferiority of LOW was established according to predefined criteria. The PSA response rate was 58% in LOW and 50% in STD, and the median PFS was approximately 9 months in both groups. Androgen levels decreased similarly in both arms. Although there was no difference in PSA response or PFS, abiraterone concentrations were higher in STD. Conclusion Low-dose AA (with low-fat breakfast) is noninferior to standard dosing with respect to PSA metrics. Given the pharmacoeconomic implications, these data warrant consideration by prescribers, payers, and patients. Additional studies are indicated to assess the long-term efficacy of this approach.
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http://dx.doi.org/10.1200/JCO.2017.76.4381DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5941614PMC
May 2018

Selective Glucocorticoid Receptor Modulators (SGRMs) Delay Castrate-Resistant Prostate Cancer Growth.

Mol Cancer Ther 2017 08 20;16(8):1680-1692. Epub 2017 Apr 20.

Department of Medicine, The University of Chicago, Chicago, Illinois.

Increased glucocorticoid receptor (GR) expression and activity following androgen blockade can contribute to castration-resistant prostate cancer (CRPC) progression. Therefore, we hypothesized that GR antagonism will have therapeutic benefit in CRPC. However, the FDA-approved nonselective, steroidal GR antagonist, mifepristone, lacks GR specificity, reducing its therapeutic potential. Here, we report that two novel nonsteroidal and highly selective GR modulators (SGRM), CORT118335 and CORT108297, have the ability to block GR activity in prostate cancer and slow CRPC progression. In contrast to mifepristone, these novel SGRMs did not affect androgen receptor (AR) signaling, but potently inhibited GR transcriptional activity. Importantly, SGRMs decreased GR-mediated tumor cell viability following AR blockade. , SGRMs significantly inhibited CRPC progression in high GR-expressing, but not in low GR-expressing xenograft models. Transcriptome analysis following AR blockade and GR activation revealed that these SGRMs block GR-mediated proliferative gene expression pathways. Furthermore, GR-regulated proliferation-associated genes , and are inhibited by CORT108297 treatment Together, these data suggest that GR-selective nonsteroidal SGRMs potently inhibit GR activity and prostate cancer growth despite AR pathway inhibition, demonstrating the therapeutic potential of SGRMs in GR-expressing CRPC. .
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http://dx.doi.org/10.1158/1535-7163.MCT-16-0923DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544558PMC
August 2017

Dynamic Contrast-Enhanced Magnetic Resonance Imaging as a Pharmacodynamic Biomarker for Pazopanib in Metastatic Renal Carcinoma.

Clin Genitourin Cancer 2017 04 17;15(2):207-212. Epub 2016 Aug 17.

Department of Medicine, Section of Hematology/Oncology, Comprehensive Cancer Center, University of Chicago, Chicago, IL. Electronic address:

Introduction/background: Traditional imaging assessment criteria might not correlate well with clinical benefit from vascular endothelial growth factor pathway-directed therapy in metastatic renal cancer. Preclinical data suggest tumor growth is preceded by a rise in K level, a parameter derived from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) that reflects vascular permeability. We thus hypothesized that K might be a predictive biomarker for pazopanib.

Patients And Methods: Patients with metastatic renal cancer were treated with pazopanib at 800 mg oral daily until disease progression. MRI of the abdomen and pelvis with a DCE-MRI sequence was obtained at baseline and every 8 weeks.

Results: Seventy-three DCE-MRI scans were completed and 66 were technically assessable. Of the 17 patients with at least 1 DCE-MRI scan after the baseline scan, 16 (94%) had a decline in K level. Changes in K compared with baseline after 1, 8, 16, and 24 weeks were -49%, -65%, -63%, and -53%, respectively (P = .0052, repeated measures analysis of variance). The median K nadir occurred at 8 weeks. The median progression-free survival (PFS) was 32.1 weeks. PFS was longer in patients with higher baseline K values (P = .036, log rank). Baseline K did not reach significance in a Cox proportional hazard model including clinical prognostic index and previous treatments (P = .083).

Conclusion: We show that K is a pharmacodynamic biomarker for pazopanib therapy in metastatic renal cancer. Because of the small sample size, the predictive capacity of K recovery could not be assessed, but baseline K correlated with PFS.
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http://dx.doi.org/10.1016/j.clgc.2016.08.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315677PMC
April 2017

Acquired resistance to the second-generation androgen receptor antagonist enzalutamide in castration-resistant prostate cancer.

Oncotarget 2016 May;7(18):26259-74

Committee on Cancer Biology, The University of Chicago, Chicago, IL, USA.

Enzalutamide (MDV3100) is a second generation Androgen Receptor (AR) antagonist with proven efficacy in the treatment of castration resistant prostate cancer (CRPC). The majority of treated patients, however, develop resistance and disease progression and there is a critical need to identify novel targetable pathways mediating resistance. The purpose of this study was to develop and extensively characterize a series of enzalutamide-resistant prostate cancer cell lines. Four genetically distinct AR-positive and AR-pathway dependent prostate cancer cell lines (CWR-R1, LAPC-4, LNCaP, VCaP) were made resistant to enzalutamide by long-term culture (> 6 months) in enzalutamide. Extensive characterization of these lines documented divergent in vitro growth characteristics and AR pathway modulation. Enzalutamide-resistant LNCaP and CWR-R1 cells, but not LAPC-4 and VCAP cells, demonstrated increased castration-resistant and metastatic growth in vivo. Global gene expression analyses between short-term enzalutamide treated vs. enzalutamide-resistant cells identified both AR pathway and non-AR pathway associated changes that were restored upon acquisition of enzalutamide resistance. Further analyses revealed very few common gene expression changes between the four resistant cell lines. Thus, while AR-mediated pathways contribute in part to enzalutamide resistance, an unbiased approach across several cell lines demonstrates a greater contribution toward resistance via pleiotropic, non-AR mediated mechanisms.
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http://dx.doi.org/10.18632/oncotarget.8456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5041979PMC
May 2016

Molecular analysis of CD133-positive circulating tumor cells from patients with metastatic castration-resistant prostate cancer.

J Transl Sci 2015 Jul 30;1(1). Epub 2015 Jul 30.

Committee on Cancer Biology, The University of Chicago, Chicago, IL, USA; Department of Surgery, Section of Urology, The University of Chicago, Chicago, IL, USA.

The function and clinical utility of stem cell markers in metastatic castration-resistant prostate cancer (mCRPC) remains unresolved, and their expression may confer important therapeutic opportunities for staging and therapy. In the adult human prostate, CD133 (PROM1) expression identifies infrequent prostate epithelial progenitor cells and putative cancer stem cells. Previous work demonstrated an association with CD133 and cancer cell proliferation using model systems. The primary objective here was to investigate the expression of CD133 in circulating tumor cells (CTCs) from patients with mCRPC and to test the hypothesis that patients with mCRPC had CD133-positive CTCs associated with increased cell proliferation, changes in the androgen receptor (AR) protein expression, or AR nuclear co-localization. We utilized ImageStreamX technology, which combines flow cytometry and fluorescence microscopy, to capture and analyze CD45-negative/EpCAM-positive CTCs for CD133, Ki-67, and AR. All patient samples (20/20) contained CD133-positive populations of CTCs, and on average 50.9 ± 28.2% (range of 18.2% to 100%) of CTCs were CD133-positive. CD133-positive CTCs have increased Ki-67 protein expression compared to CD133-negative CTCs, implying that CD133-positive CTCs may have greater proliferative potential when compared to their CD133-negative counterparts. CD133-positive and CD133-negative CTCs have similar levels of AR protein expression and cellular co-localization with nuclear markers, implying that CD133 expression is independent of AR pathway activity and an AR-independent marker of mCRPC proliferation. These studies demonstrate the presence of CD133-positive populations in CTCs from mCRPC with increased proliferative potential.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4704802PMC
July 2015

Saracatinib as a metastasis inhibitor in metastatic castration-resistant prostate cancer: A University of Chicago Phase 2 Consortium and DOD/PCF Prostate Cancer Clinical Trials Consortium Study.

Prostate 2016 Feb 23;76(3):286-93. Epub 2015 Oct 23.

Genitourinary Oncology Program, Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, Illinois.

Background: Fyn is a kinase that is upregulated in a subset of metastatic castration-resistant prostate cancer. Saracatinib potently inhibits Fyn activation. We have noted a relationship between Fyn expression and directional motility, a cellular process related to metastasis. As such we hypothesized that treatment with saracatinib would increase the time required to develop new metastatic lesions.

Methods: Patients with metastatic castration-resistant prostate cancer that had progressed after docetaxel were eligible for enrollment. This study was executed as a randomized discontinuation trial. During a lead-in phase of two 28-Day cycles, all patients received saracatinib. Afterward, patients with radiographically stable disease were randomized to either saracatinib or placebo. Patients continued treatment until evidence of new metastasis.

Results: Thirty-one patients were treated. Only 26% of patients had stable disease after 8 weeks and thus proceeded to randomization. This required early termination of the study for futility. The 70% of patients who progressed after the lead-in phase exhibited expansion of existing lesions or decompensation due to clinical progression without new metastatic lesions. Fatigue was reported in more than 25% of patients (all grades) with only two patients experiencing grade 3 toxicity. Other grade 3 adverse events included dehydration, thrombocytopenia, and weakness.

Conclusions: This study was unable to determine if saracatinib had potential as metastasis inhibitor. Metastasis inhibition by saracatinib may still be viable in an earlier time in the disease history.
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http://dx.doi.org/10.1002/pros.23119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4904773PMC
February 2016

Targeting the glucocorticoid receptor in breast and prostate cancers.

Sci Transl Med 2015 Sep;7(305):305ps19

Department of Medicine, Section of Hematology/Oncology, The University of Chicago, 5841 S. Maryland Avenue, MC 2115, Chicago, IL 60637, USA.

Steroid receptors for androgens and estrogens have essential roles in prostate and breast cancers. Recently, glucocorticoid receptor (GR) activity has also been proposed as having an important role in these cancers. Underscoring the cooperative nature of nuclear receptor activity, data now suggest that GR function in prostate and breast cancers is dependent on the tumor's concomitant androgen or estrogen receptor activity.
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http://dx.doi.org/10.1126/scitranslmed.aac7531DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807967PMC
September 2015

Sustained Complete Response to Cytotoxic Therapy and the PARP Inhibitor Veliparib in Metastatic Castration-Resistant Prostate Cancer - A Case Report.

Front Oncol 2015 22;5:169. Epub 2015 Jul 22.

Department of Medicine, University of Chicago , Chicago, IL , USA.

Solid tumors harboring BRCA1 or BRCA2 mutations have been shown to respond to PARP inhibitors. These responses are partial and transient. In this case report, we describe an 82-year-old male with poorly differentiated prostate cancer with metastases to the lung, liver, abdomen, and bowel. Molecular testing demonstrated alterations in BRCA2, ERG, and TP53. Based on this result, he was enrolled in a therapeutic trial and received carboplatin, gemcitabine, and veliparib, to which he had a partial response. He continued to respond while on veliparib maintenance alone, and after 38 cycles he had a sustained complete response. A sustained complete response to PARP inhibitor-based therapy has not previously been described for prostate cancer. This case suggests that cytotoxic therapy in combination with PARP inhibitors may yield exceptional responses, and molecular studies may help guide patient selection for these therapies.
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http://dx.doi.org/10.3389/fonc.2015.00169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510409PMC
August 2015

Quantitative characterization of androgen receptor protein expression and cellular localization in circulating tumor cells from patients with metastatic castration-resistant prostate cancer.

J Transl Med 2014 Nov 26;12:313. Epub 2014 Nov 26.

Department of Medicine, University of Chicago, Chicago, IL, USA.

Background: Many current therapies for metastatic castration-resistant prostate cancer (mCRPC) are aimed at AR signaling; however, resistance to these therapies is inevitable. To personalize CRPC therapy in an individual with clinical progression despite maximal AR signaling blockade, it is important to characterize the status of AR activity within their cancer. Biopsies of bone metastases are invasive and frequently fail to yield sufficient tissue for further study. Evaluation of circulating tumor cells (CTCs) offers an alternative, minimally invasive mechanism to characterize and study late-stage disease. The goal of this study was to evaluate the utility of CTC interrogation with respect to the AR as a potential novel therapeutic biomarker in patients with mCRPC.

Methods: Fifteen mL of whole blood was collected from patients with progressive, metastatic mCRPC, the mononuclear cell portion was isolated, and fluorescence-activated cell sorting (FACS) was used to isolate and evaluate CTCs. A novel protocol was optimized to use ImageStreamX to quantitatively analyze AR expression and subcellular localization within CTCs. Co-expression of AR and the proliferation marker Ki67 was also determined using ImageStreamX.

Results: We found inter-patient and intra-patient heterogeneity in expression and localization of AR. Increased AR expression and nuclear localization are associated with elevated co-expression of Ki-67, consistent with the continued role for AR in castration-resistant disease. Despite intra-patient heterogeneity, CTCs from patients with prior exposure to abiraterone had increased AR expression compared to CTCs from patients who were abiraterone-naïve.

Conclusions: As our toolbox for targeting AR function expands, our ability to evaluate AR expression and function within tumor samples from patients with late-stage disease will likely be a critical component of the personalized management of advanced prostate cancer. AR expression and nuclear localization varies within patients and between patients; however it remains associated with markers of proliferation. This supports a molecularly diverse AR-centric pathobiology imparting castration-resistance.
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http://dx.doi.org/10.1186/s12967-014-0313-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4252013PMC
November 2014

Sequential use of the androgen synthesis inhibitors ketoconazole and abiraterone acetate in castration-resistant prostate cancer and the predictive value of circulating androgens.

Clin Cancer Res 2014 Dec 21;20(24):6269-76. Epub 2014 Oct 21.

Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California.

Purpose: Patients previously treated with ketoconazole were excluded from phase III trials of abiraterone acetate due to potential overlapping mechanism of action. The purpose of this study was to determine the clinical utility of abiraterone and its impact on circulating androgens following ketoconazole.

Experimental Design: Chemotherapy-naïve patients with progressive metastatic castration-resistant prostate cancer (mCRPC) and prior ketoconazole therapy ≥28 days received abiraterone acetate 1,000 mg daily and prednisone 5 mg twice daily. The primary endpoint was the proportion of patients with PSA response, defined as ≥30% PSA decline at 12 weeks. H0 = 0.30 versus H1 = 0.50 (α = 0.05, power = 0.83). Circulating androgen levels were measured using liquid chromatography tandem mass spectrometry.

Results: Thirty-nine patients were included in the final analysis. Twenty (51%; 95% confidence interval, 36%-66%) patients had ≥30% PSA decline; the null hypothesis was rejected. Sixteen (41%) had ≥50% PSA decline. Median PFS (progression-free survival) was 16 weeks; median radiographic PFS (rPFS) was 36 weeks. Samples for measurement of baseline androgens were available in 37 patients. The PSA response proportion was 59% in 29 patients with DHEA ≥ limit of quantitation (LOQ), compared with 13% in 8 patients with DHEA < LOQ (P = 0.042). Median PFS was 6 and 16 weeks in DHEA < LOQ and DHEA ≥ LOQ patients, respectively (P = 0.017); median rPFS was 14 and 36 weeks in DHEA < LOQ and DHEA ≥ LOQ patients, respectively (P < 0.001).

Conclusions: Abiraterone demonstrates modest clinical efficacy in mCRPC patients previously treated with ketoconazole. Patients with DHEA ≥ LOQ were more likely to demonstrate PSA responses and longer PFS. Analysis of circulating androgens merits further investigation as a biomarker for response to androgen synthesis inhibitor therapy.
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http://dx.doi.org/10.1158/1078-0432.CCR-14-1595DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4277885PMC
December 2014

The pluripotency factor Nanog is directly upregulated by the androgen receptor in prostate cancer cells.

Prostate 2014 Nov 31;74(15):1530-43. Epub 2014 Aug 31.

Committee on Cancer Biology, The University of Chicago, Chicago, Illinois; Department of Surgery, Section of Urology; The University of Chicago, Chicago, Illinois.

Background: The Androgen Receptor (AR) is a nuclear hormone receptor that functions as a critical oncogene in all stages of prostate cancer progression, including progression to castration-resistance following androgen-deprivation therapy. Thus, identifying and targeting critical AR-regulated genes is one potential method to block castration-resistant cancer proliferation. Of particular importance are transcription factors that regulate stem cell pluripotency; many of these genes are emerging as critical oncogenes in numerous tumor cell types. Of these, Nanog has been previously shown to increase the self-renewal and stem-like properties of prostate cancer cells. Thus, we hypothesized that Nanog is a candidate AR target gene that may impart castration-resistance.

Methods: We modulated AR signaling in LNCaP prostate cancer cells and assayed for Nanog expression. Direct AR binding to the NANOG promoter was tested using AR Chromatin Immunoprecipation (ChIP) and analyses of publically available AR ChIP-sequencing data-sets. Nanog over-expressing cells were analyzed for cell growth and cytotoxicity in response to the AR antagonist enzalutamide and the microtubule stabilizing agent docetaxel.

Results: AR signaling upregulates Nanog mRNA and protein. AR binds directly to the NANOG promoter, and was not identified within 75 kb of the NANOGP8 pseudogene, suggesting the NANOG gene locus was preferentially activated. Nanog overexpression in LNCaP cells increases overall growth, but does not increase resistance to enzalutamide or docetaxel.

Conclusions: Nanog is a novel oncogenic AR target gene in prostate cancer cells, and stable expression of Nanog increases proliferation and growth of prostate cancer cells, but not resistance to enzalutamide or docetaxel.
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http://dx.doi.org/10.1002/pros.22870DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4174985PMC
November 2014

Corticosteroids and prostate cancer: friend or foe?

Eur Urol 2015 May 20;67(5):874-5. Epub 2014 Aug 20.

Fox Chase Cancer Center, Temple Health, Philadelphia, PA, USA. Electronic address:

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http://dx.doi.org/10.1016/j.eururo.2014.08.008DOI Listing
May 2015