PRESTO: A Phase III, Open-Label Study of Intensification of Androgen Blockade in Patients With High-Risk Biochemically Relapsed Castration-Sensitive Prostate Cancer (AFT-19)

PURPOSE

Patients with biochemically recurrent prostate cancer (BRPC) after radical prostatectomy and a short PSA doubling time are at risk for distant metastases. Apalutamide, an androgen receptor antagonist, and abiraterone acetate plus prednisone (AAP) prolong survival in the metastatic setting. We evaluated whether intensification of androgen-deprivation therapy (ADT) improves outcomes in BRPC.

PATIENTS AND METHODS

PRESTO is a randomized phase III, open-label trial in patients with BRPC and PSA doubling time ≤9 months (ClinicalTrials.gov identifier: NCT03009981). Patients were randomly assigned 1:1:1 to receive a finite 52-week treatment course with ADT control, ADT + apalutamide, or ADT + apalutamide + AAP. The primary end point was PSA progression-free survival (PSA-PFS), defined as serum PSA >0.2 ng/mL after treatment completion.

RESULTS

Five hundred three patients were enrolled. The median PSA was 1.8 ng/mL (IQR, 1.0-3.6). At the first planned interim analysis, both experimental arms significantly prolonged PSA-PFS compared with the control arm (median, 24.9 months for ADT + apalutamide v 20.3 months for ADT; hazard ratio [HR], 0.52 [95% CI, 0.35 to 0.77]; P = .00047; median, 26.0 months for ADT + apalutamide + AAP v 20.0 months for ADT; HR, 0.48 [95% CI, 0.32 to 0.71]; P = .00008). Median time to testosterone recovery did not differ across treatment arms. The most common grade ≥3 adverse event was hypertension (7.5%, 7.4%, and 18% in ADT, ADT + apalutamide, and ADT + apalutamide + AAP arms, respectively).

CONCLUSION

Intensified AR blockade for a finite duration prolongs PSA-PFS with a manageable safety profile, without adversely affecting time to testosterone recovery. The addition of apalutamide to ADT should be considered in patients with high-risk BRPC.

Microbial Biofilm: A Review on Formation, Infection, Antibiotic Resistance, Control Measures, and Innovative Treatment

Biofilm is complex and consists of bacterial colonies that reside in an exopolysaccharide matrix that attaches to foreign surfaces in a living organism. Biofilm frequently leads to nosocomial, chronic infections in clinical settings. Since the bacteria in the biofilm have developed antibiotic resistance, using antibiotics alone to treat infections brought on by biofilm is ineffective. This review provides a succinct summary of the theories behind the composition of, formation of, and drug-resistant infections attributed to biofilm and cutting-edge curative approaches to counteract and treat biofilm. The high frequency of medical device-induced infections due to biofilm warrants the application of innovative technologies to manage the complexities presented by biofilm.

Baseline characteristics associated with PSA progression-free survival in patients (pts) with high-risk biochemically relapsed prostate cancer: Results from the phase 3 PRESTO study (AFT-19)

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Background: In the Phase 3 PRESTO study, intensified androgen deprivation therapy (ADT) with apalutamide (APA) with or without abiraterone acetate plus prednisone (AAP), administered for a finite treatment period of 52 weeks, prolonged prostate-specific antigen progression-free survival (PSA PFS) in pts with high-risk biochemically relapsed prostate cancer (BRPC). We evaluated baseline factors associated with PSA PFS in this study. Methods: PRESTO is a randomized phase 3, open-label trial in pts with BRPC following radical prostatectomy (RP) and PSA doubling time (PSADT) ≤ 9 months (mo), without distant metastases on conventional imaging (NCT03009981). Pts were randomized 1:1:1 to receive a finite 52-week treatment course with ADT, ADT + APA, or ADT + APA + AAP, stratified by PSADT (< 3 vs 3–9 mo), with post-treatment follow-up. Baseline factors associated with PSA PFS including Gleason sum at RP (6-7, 8, ≥ 9) were analyzed in a post hoc fashion. Results: 504 pts were randomized to ADT alone (N = 167), ADT + APA (N = 168) or ADT + APA + AAP (N = 169). Baseline patient characteristics including Gleason sum at diagnosis, serum PSA and PSADT at study entry, time interval from radical prostatectomy, and receipt of prior radiation (none, adjuvant, salvage) were well balanced across the three treatment arms. At the first planned interim analysis, both experimental arms significantly prolonged PSA PFS compared to the control arm (median 24.9 mo for ADT + APA vs 20.3 mo for ADT, HR = 0.52 (95% CI: 0.35–0.77); median 26.0 mo for ADT + APA + AAP vs 20.0 mo for ADT, HR = 0.48 (95% CI: 0.32–0.71)). Across the study cohort, Gleason sum ≥ 9 at diagnosis was associated with shorter PSA PFS (median 21.9 mo for Gleason ≥ 9 vs. 31.1 mo for Gleason 8 vs. 25.2 mo for Gleason 6-7, log-rank p-value = 0.0409). In addition, within each treatment arm, a shorter observed median PSA PFS was detected for patients with Gleason ≥ 9 prostate cancer. Serum PSA and PSADT at study entry, time from prior radical prostatectomy, and prior radiation were not associated with PSA PFS in the overall study cohort or in individual study arms. Conclusions: Gleason sum ≥ 9 prostate cancer at diagnosis was associated with shorter time to PSA progression following subsequent intensified ADT administered for a finite treatment interval in BRPC. Follow-up is ongoing to integrate genomic profiling of primary prostate cancer tissue with these results and validate with longer term endpoints including metastasis-free survival. Clinical trial information: NCT03009981 .

Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction

Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction.

The effect of vibratory stimulation on the timed-up-and-go mobility test: a pilot study for sensory-related fall risk assessment

Effects of localized lower-extremity vibration on postural balance have been reported. The purpose of the current study was to investigate the effect of low-frequency vibration of calf muscles on the instrumented Timed-Up-and-Go (iTUG) test among older adults. Older adults were recruited and classified to low (n=10, age=72.9±2.8 years) and high fall risk (n=10, age=83.6±9.6) using STEADI. Vibratory system (30Hz or 40Hz), was positioned on calves along with wearable motion sensors. Participants performed the iTUG test three times, under conditions of no-vibration, 30Hz, and 40Hz vibration. Percentage differences in duration of iTUG components were calculated comparing vibration vs no-vibration conditions. Significant between-group differences were observed in iTUG (p=0.03); high fall risk participants showed reduction in the duration of turning (-10 % with 30Hz; p=0.15 and -15 % with 40Hz; p=0.03) and turning and sitting (-18 % with 30Hz; p=0.02 and -10 % with 40Hz; p=0.08). However, vibration increased turning (+18 % with 30Hz; p=0.20 and +27 % with 40Hz; p=0.12) and turning and sitting duration (+27 % with 30Hz; p=0.11 and +47 % with 40Hz; p=0.12) in low fall risk participants. Findings suggest that lower-extremity vibration affects dynamic balance; however, the level of this influence may differ between low and high fall risk older adults, which can potentially be used for assessing aging-related sensory deficits.

Abstract B087: Role of GATA-4-Androgen-AR axis in prostate cancer from African American men

Background: African American (AA) men are 1.7 times more likely to develop and 2.4 times more likely to die of prostate cancer (PrCa) than their European American (EA) counterparts, however the underlying biology causing this disparity is unknown. Here, we show how epigenetic dysregulation of calcium signaling genes affect GATA-4, androgen receptor (AR), androgen metabolism and associate with clinical outcomes in AA men with PrCa. Methods: Using Illumina arrays we identified DNA methylation differences between 32 EA and AA PrCa patients. We used RNA-sequencing to discover transcriptomic changes potentially mediated by DNA methylation. We measured GATA-4 and AR protein expression in a tissue microarray (TMA) of 95 EA and 92 AA PrCa patients. We measured testosterone (T) and dihydrotestosterone (DHT) in serum of the same AA and EA PrCa patients. In vitro, we treated MDA PCa 2a (2a) and LaPC4 cells derived from AA and EA prostate tumors, respectively with a calcium chelator (BAPTA-AM) and T. We measured GATA-4 and AR protein expression in control and treated cells. Results: Our DNA methylation analysis showed that AA but not EA prostate tumors enriched for hypermethylated sites in calcium sensing genes was associated with worse disease-free time (21.6 vs 46.7 months, p&lt;0.05). DNA hypermethylation of calcium signaling genes, which correlated with decreased transcript levels, can potentially raise intracellular calcium. Calcium levels regulate stability of proteins including AR and GATA-4. Therefore, we tested potential calcium mediated changes in GATA-4 and AR expression in vitro and in patient samples. In vitro, depleting calcium in the presence of T increased GATA-4 protein expression by 1.5 times and AR expression only in AA prostate tumor derived 2a cells. DNA hypermethylation of calcium sensing genes was associated with lower GATA-4 and AR expression in PrCa and adjacent non-tumor tissues of AA men. The role of GATA-4 in PrCa is unknown, but it is a known transcriptional regulator of androgen metabolizing enzymes (AME). AMEs are important for androgen metabolism that result in T and DHT production through the primary and alternative pathways. AME transcripts in the primary and alternative pathways were one of the top 5 transcriptionally dysregulated pathways in AA compared to EA prostate tumors. We found that T but not DHT is significantly lower (p&lt;0.05) in serum samples from AA (3.64ng/ml) compared to EA (3.99ng/ml) PrCa patients. T and DHT bioavailability in prostate tumors affect AR expression and function. In our studies, AA adjacent non-tumor tissues had higher percent AR positive nuclei (p&lt;0.05) compared to EA adjacent non-tumor tissues. Conclusion: Epigenetic alteration of calcium signaling can affect GATA-4 mediated changes in androgen metabolism and AR signaling that are well-established therapeutic targets in PrCa. This molecular alteration, unique to AA prostate tumors, can be used to rationalize specific androgen deprivation and AR-targeted therapies in these patients.

Citation Format: Swathi Ramakrishnan, Xuan Peng, Eduardo Cortes Gomez, Kristopher Attwood, Li Yan, John Wilton, Gissou Azabdaftari, James Mohler, Jianmin Wang, Anna Woloszynska. Role of GATA-4-Androgen-AR axis in prostate cancer from African American men [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B087.

CALGB 90203 (Alliance): Radical prostatectomy (RP) with or without neoadjuvant chemohormonal therapy (CHT) in men with clinically localized, high-risk prostate cancer (CLHRPC)

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Background: Neoadjuvant CHT followed by RP did not increase 3-year biochemical progression free-survival (bPFS) compared to RP alone in men with CLHRPC. However, there is evidence that bPFS and overall survival over time was improved. In the current analysis we assessed whether CHT followed by RP improved pathological specimen features compared to RP alone. Methods: CALGB 90203 (Alliance) is a Phase III study which randomly assigned, in a 1:1 fashion, men with CLHRPC [biopsy Gleason Grade Group (GGG) 4 or 5 or Kattan pre-op nomogram bPFS < 60%] to RP alone or RP plus neoadjuvant CHT [androgen deprivation plus docetaxel (75 mg/m2 every 3 weeks for 6 cycles)]. We conducted an exploratory analysis comparing histologic findings, determined at the treating center, in the RP specimens of men receiving CHT plus RP and men treated with RP alone. We used the Chi-square test, with P-values adjusted by the Holm method for multiple comparisons. Results: A total of 788 men (median age, 62; range: 32-83 years) were randomized, with 738 ultimately undergoing RP. There was no difference in pathologic GGG (Table). Men treated with neoadjuvant CHT had a lower pathologic T-stage and lower likelihood of having seminal vesicle invasion (SVI), positive pelvic lymph nodes, or positive surgical margins (SM) (Table). Conclusions: Most pathologic features in the RP specimen were improved in men receiving neoadjuvant CHT compared to RP alone. The relationship between pathologic changes and the development of metastasis and survival require further analysis. RP pathologic outcomes. Summary statistics are calculated for the number of patients with non-missing data for each characteristic. Clinical trial information: NCT00430183. [Table: see text]

Differences in immune tumor microenvironment between primary and metastatic castration-resistant prostate cancer

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Background: Androgen deprivation therapy (ADT)-induced immunosuppression has been described in animal models as contributing to castration-resistant prostate cancer (CRPC) development, but the clinical relevance of these observations has not been established. In this study, we compared the immune tumor microenvironment (iTME) of primary prostate cancer (PPC) versus metastatic CRPC (mCRPC). Methods: Genomic and clinically annotated data were obtained of PPC and mCRPC from the TCGA provisional and SU2C/PCF databases. Patients without RNA-seq data were excluded. 22 iTME cell subsets were estimated using CIBERSORT LM22 algorithm. Relative cell proportions and gene expression in log-transformed FPKM were compared using Wilcoxon tests. Results: 499 PPC and 118 mCRPC were studied. Compared to PPC, mCRPC had higher percentage of M2 macrophages (24.6% vs. 10.2%, p<0.0001). High M2 in mCRPC was associated with 2.5-, 6- and 19.5-fold increases in IL-10, VEGFA and ARG1 mRNA levels, respectively (p<0.0001). T- cell exhaustion markers, LAG3 and CD160, were upregulated in mCRPC by 43.2% and 266.7% (p<0.0001). Although CD8 T-cells were higher in mCRPC, the CD8/M2 ratio was lower (1.1 vs. 1.5, p=0.002). Prior use of abiraterone or enzalutamide in the mCRPC cohort (n=54) did not alter iTME cell fractions compared to AR antagonist naïve mCRPC. The detailed iTME comparisons were listed in Table. Conclusions: Our data indicate the development of tumor-favoring iTME in the course of progression to mCRPC while on ADT. The iTME is characterized by increased M2 macrophage infiltration that may provide a novel and important therapeutic target. [Table: see text]

Abstract A003: Epigenetic alterations as potential biologic determinants of racial health disparities

Background: Biologic determinants of prostate cancer racial health disparities remain largely unknown. African American (AA) men are diagnosed with more aggressive prostate cancer than European American (EA) men despite presenting tumors with lower mutational burden, copy number alterations, and lacking ETS gene fusions. The purpose of our study is to investigate how DNA methylation alterations in the context of other molecular lesions contribute to aggressive prostate cancer in AA men.

Methods: We measured DNA methylation and gene expression in twelve radical prostatectomy specimens from AA patients treated at Roswell Park Cancer (RPCI) Institute by Infinium DNA methylation arrays and RNA-sequencing, respectively. Additional AA (n=22)/EA (n=5) patients from RPCI and AA (n=22)/EA (n=172) patients from The Cancer Genome Atlas (TCGA) were included in the clustering analysis to raise statistical power of our study. The MethylMix pipeline was applied to DNA methylation and gene expression to identify transcripts that are potentially regulated by DNA methylation.

Results: Unsupervised hierarchical clustering revealed 2 large clusters, Cluster1 (n=133) and Cluster3 (n=73). AA patients in Cluster1 presented with better overall survival (57 vs. 50 months, p=0.48) and disease-free time (47 vs. 22 months, p&lt;0.05) compared to AA patients in Cluster3. We did not observe this difference in clinical outcomes for EA patients. Cluster3 consisted of hypomethylated CG sites belonging primarily to neurogenesis development and the Wnt/Hedgehog signaling pathways. TMPRSS2-ERG fusion status thought to drive aggressive prostate cancer was similar in all clusters. Interestingly, promoter DNA methylation of ERG gene was significantly lower at 5 CG sites (p&lt;0.0001) and at 10 CG sites in the 5′-UTR region (p&lt;0.0001) in fusion-positive EA patients as compared to fusion-negative EA patients. In tumors of AA patients, DNA methylation of ERG gene was significantly lower at 2 CG sites at the transcription start site (p&lt;0.05) and at 1 CG site in the 5′-UTR region (p&lt;0.05) in fusion-positive tumors as compared to fusion-negative tumors. Overall DNA methylation at the ERG negatively correlated with ERG gene expression (Pearson: -0.632). Furthermore, we used MethylMix algorithm that revealed DNA methylation as a potential negative regulator of genes involved in suppression of tumor invasion, glycosylation of mucin proteins, calcium sensing, and terminal differentiation specifically in AA patients. For a subset of these genes we observed altered transcript levels in AA tumor samples compared to EA tumor samples from the TCGA cohort. This included GALNT5 (-0.23 vs 0.15, p&lt;0.05), STK39 (-0.30 vs 0.03, p&lt;0.05), and TMEM63C (46.68 vs 22.65, p&lt;0.05).

Conclusions: Our work reveals that there are epigenetic alterations found in prostate tumors that are specific to AA men. Moreover, this differential gene methylation may have subsequent impact on gene expression and contribute to more aggressive prostate cancer. We identified novel transcripts in AA patients that are potentially regulated by DNA methylation including ERG, GALNT5, STK39, and TMEM63C. Functional validation of these genes using prostate cancer models may provide insight into whether epigenetic regulation of these genomic loci are determinants of prostate cancer racial health disparities.

Citation Format: Swathi Ramakrishnan, Peng Xuan, Qianya Qi, Qiang Hu, Emily Ellman, Gissou Azabdaftari, Elena Pop, James Mohler, Kristopher Attwood, Yan Li, Jianmin Wang, Anna Woloszynska-Read. Epigenetic alterations as potential biologic determinants of racial health disparities [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr A003.

Abstract B72: DNA methylation and genetic alterations contribute to aggressive prostate cancer in African American men

Background: African-American (AA) men are more often diagnosed with early-onset aggressive prostate cancer than European American (EA) men. Prostate cancer health disparities between AA and EA men are attributed to socioeconomic as well as biologic differences existing between the two groups. The purpose of this study is to investigate how genetic and epigenetic alterations, specifically DNA methylation, contribute to early-onset aggressive prostate cancer in AA men.

Methods: We performed 450K methylation array and RNA-sequencing on radical prostatectomy specimens from AA (n=32) and EA (n=5) men treated at Roswell Park Cancer Institute (RPCI). To increase analytical power, we included AA (n=22) and EA (n=172) patients from The Cancer Genome Atlas (TCGA) database. We found no significant difference in the average age between EA and AA men in the RPCI cohort, but the TCGA cohort consisted of AA men who had significantly lower average and median age compared to EA men (57 and 56 vs 61 and 62; p=0.019). We assessed baseline androgen receptor (AR) protein levels in matched benign and malignant AA (n=95) and EA (n=93) radical prostatectomy tissues from RPCI using immunohistochemistry. Gleason score &lt;3+4 and &gt;4+3 were classified as low and high aggressive tumors, respectively.

Results: Unsupervised hierarchical clustering of DNA methylation levels in prostate cancers revealed 9 clusters. We focused on the 2 largest clusters, Cluster 1 (n=133) and Cluster 3 (n=73). Cluster 1 consisted predominantly of low aggressive disease (p=0.00002) with lower serum prostate specific antigen (PSA) values (8.97 vs 13.35 ng/ml) compared to Cluster 3. Following this trend, AA patients, but not EA patients, in Cluster 1 had better overall (57 vs 50 months, p=0.48) and disease-free time (47 vs 22 months, p=0.01) as compared to Cluster 3. ERG (ETS-related gene) fusion-positive prostate cancer is believed to be more aggressive than fusion-negative prostate cancer due to increased ERG gene transcription. We did not observe a difference in fusion status between the two DNA methylation clusters. However, overall DNA methylation was higher in fusion-negative samples as compared to fusion-positive samples in the TCGA dataset. ERG is known to bind to and reduce PSA, a direct downstream AR target. In the TCGA dataset, AA fusion-negative patients had higher average and median preoperative PSA values (18.38, 20.15 ng/ml) as compared with AA fusion-positive (7.51, 6.70 ng/ml), EA fusion-positive (9.43, 7.00 ng/ml), and EA fusion-negative patients (11.47, 7.50 ng/ml). There was no significant difference in the AR transcript and AR protein levels between fusion-positive and -negative AA and EA men. AR protein expression in RPCI cohort tissue microarrays showed that adjacent nontumor tissues from AA men had higher percent AR positive nuclei (p&lt;0.05) compared to adjacent nontumor tissues from EA men.

Conclusions: Analysis of the RPCI and TCGA cohorts indicated that DNA methylation separated low and high aggressive prostate cancer in AA men. Further analysis will include more patients as well as identify differences in specific CpG loci between Cluster 1 and Cluster 3. Our results suggest that DNA methylation alterations can be important in patients with ERG fusion-negative disease since these prostate cancers exhibit higher levels of overall DNA methylation. Lastly, our observations of higher AR expression in adjacent nontumor tissues suggest that there are underlying genetic variations that contribute to early-onset high aggressive prostate cancer in AA men compared to EA men.

Citation Format: Swathi Ramakrishnan, Xuan Peng, Qianya Qi, Qiang Hu, Gissou Azabdaftari, Elena Pop, James Mohler, Kristopher Attwood, Li Yan, Jianmin Wang, Anna Woloszynska-Read. DNA methylation and genetic alterations contribute to aggressive prostate cancer in African American men [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr B72.

Men's Eating and Living (MEAL) study (CALGB 70807 [Alliance]): recruitment feasibility and baseline demographics of a randomized trial of diet in men on active surveillance for prostate cancer

OBJECTIVE

To assess the feasibility of performing national, randomized trials of dietary interventions for localized prostate cancer.

METHODS

The Men's Eating and Living (MEAL) study (CALGB 70807 [Alliance]) is a phase III clinical trial testing the efficacy of a high-vegetable diet to prevent progression in patients with prostate cancer on active surveillance (AS). Participants were randomized to a validated diet counselling intervention or to a control condition. Chi-squared and Kruskal-Wallis analyses were used to assess between-group differences at baseline.

RESULTS

Between 2011 and 2015, 478 (103%) of a targeted 464 patients were randomized at 91 study sites. At baseline, the mean (sd) age was 64 (6) years and mean (sd) PSA concentration was 4.9 (2.1) ng/mL. Fifty-six (12%) participants were African-American, 17 (4%) were Hispanic/Latino, and 16 (3%) were Asian-American. There were no significant between-group differences for age (P = 0.98), race/ethnicity (P = 0.52), geographic region (P = 0.60), time since prostate cancer diagnosis (P = 0.85), PSA concentration (P = 0.96), clinical stage (T1c or T2a; P = 0.27), or Gleason sum (Gleason 6 or 3+4 = 7; P = 0.76). In a pre-planned analysis, the baseline prostate biopsy samples of the first 50 participants underwent central pathology review to confirm eligibility, with an expectation that <10% would become ineligible. One of 50 participants (2%) became ineligible.

CONCLUSION

The MEAL study shows the feasibility of implementing national, multi-institutional phase III clinical trials of diet for prostate cancer and of testing interventions to prevent disease progression in AS.

Expression of NY-ESO-1 cancer testis antigen in prostate cancer

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Background: Poor outcomes in castrate resistant prostate cancer (CRPC) patients is a growing concern urging the need for innovative treatments. Cancer testis antigens (CTAs) like NY-ESO-1 are aberrantly expressed in several cancers including prostate cancer (PC). Given its tumor-restricted expression and ability to elicit spontaneous cytotoxic & antibody-mediated immune responses, NY-ESO-1 shows promise as an immunotherapy target. With the expertise of RPCI in NY-ESO-1 targeted therapeutics and limited information on NY-ESO-1 expression in CRPC, we sought this study. Methods: Immunohistochemical expression of NY-ESO-1 was analyzed in a series of PC samples from 2 different institutions. Two TMAs consisted of triplicate cores from 37 patients with localized PC (with cores from cancerous areas & the normal tissue adjacent to it), and 36 mCRPC patients. We also included 17 mCRPC whole sections for analyses. Intensity and percentage of NY-ESO-1 staining were recorded. The intensity was characterized as low (0-1+) and high (2-3+). Results: The median age in this cohort was 62 years. NY-ESO-1 IHC was positive for cytoplasmic staining in 33 of 111 (26.4%) evaluable cases including 41% in localized PC, 22.6% in benign areas adjacent to tumor, and 35.5% in CRPC. 23 (18.4%) had 1+, 7 (5.6%) had 2+ and 3 (2.4%) had 3+ cytoplasmic staining intensity. No statistical difference was noted in cytoplasmic staining with tumor grade. Gleason grade 8 -10 tumors (33 of 103 [35.4%]) correlated with lower intensity staining (0-1+) pattern (p = 0.028). NY-ESO-1 expression did not correlate with age, race, disease free or overall survival in this cohort. Conclusions: Heterogeneous NY-ESO-1 expression in PC and other tumors is linked to DNA methylation status of its promoter and tumor cells. We noted NY-ESO-1 expression in a third of the patients with CRPC, making it a credible immunotherapeutic target. NY-ESO-1 expression has been shown to be induced and upregulated in cancer by treatment with demethylating agent. Thus targeting NY-ESO-1 in concert with epigenetic modulation maybe therapeutically meaningful in patients with CRPC. Additional efforts at validating NY-ESO-1 expression in CRPC with CLIA approved IHC and qPCR assays (Omniseq) are ongoing and will be reported.

Tobacco use and outcome in radical prostatectomy patients

Cigarette smoking has been consistently associated with increased risk of overall mortality, but the importance of smoking for patients with prostate cancer (CaP) who are candidates for curative radical prostatectomy (RP) has received less attention. This retrospectively designed cohort study investigated the association of smoking history at RP with subsequent CaP treatment outcomes and overall mortality. A total of 1981 patients who underwent RP at Roswell Park Cancer Institute (RPCI) between 1993 and 2014 were studied. Smoking history was considered as a risk factor for overall mortality as well as for currently accepted CaP treatment outcomes (biochemical failure, treatment failure, distant metastasis, and disease‐specific mortality). The associations of smoking status with these outcomes were tested by Cox proportional hazard analyses. A total of 153 (8%) patients died during follow‐up. Current smoking at diagnosis was a statistically significant predictor of overall mortality after RP (current smokers vs. former and never smokers, hazards ratio 2.07, 95% confidence interval [CI]: 1.36–3.14). This association persisted for overall mortality at 3, 5, and 10 years (odds ratios 2.07 [95% CI: 1.36–3.15], 2.05 [95% CI: 1.35–3.12], and 1.8 [95% CI: 1.18–2.74], respectively). Smoking was not associated with biochemical failure, treatment failure, distant metastasis, or CaP‐specific mortality, and the association of smoking with overall mortality did not appear to be functionally related to treatment or biochemical failure, or to distant metastasis. Smoking is a non‐negligible risk factor for death among CaP patients who undergo RP; patients who smoke are far more likely to die of causes other than CaP.

NCCN Clinical Practice Guidelines Prostate Cancer Early Detection, Version 2.2015

Prostate cancer represents a spectrum of disease that ranges from nonaggressive, slow-growing disease that may not require treatment to aggressive, fast-growing disease that does. The NCCN Guidelines for Prostate Cancer Early Detection provide a set of sequential recommendations detailing a screening and evaluation strategy for maximizing the detection of prostate cancer that is potentially curable and that, if left undetected, represents a risk to the patient. The guidelines were developed for healthy men who have elected to participate in the early detection of prostate cancer, and they focus on minimizing unnecessary procedures and limiting the detection of indolent disease.

Abstract 806: SNPs in vitamin D-related genes are associated with prostate cancer aggressiveness in the North Carolina-Louisiana Prostate Cancer Project (PCaP)

Introduction: African Americans have higher incidence of, and mortality from, prostate cancer (PCa) compared to other racial/ethnic groups. Frequency of polymorphisms in genes involved in vitamin D metabolism, transport, and activity differ by race/ethnicity. Examining the association between polymorphisms in vitamin D-related genes and PCa aggressiveness may explain differing susceptibility to aggressive PCa among individuals and across different racial/ethnic groups.

Methods: TagSNPs (n = 315) in 13 genes (VDR, GC, CYP24A1, CYP27A1, CYP27B1, CYP2R1, CYP3A4, DHCR7, CASR, NADSYN1, RXRA, RXRB, RXRG) were genotyped using Illumina GoldenGate or Sequenom assays in 524 African-American and 657 European-American men with newly-diagnosed PCa from PCaP. DNA extracted from blood samples collected at enrollment was stored at -80C prior to analyses. Research subjects were classified as high aggressive if Gleason sum ≥8, or Gleason score (4+3), or PSA &gt;20 ng/ml, or Gleason score (3+4) AND clinical stage = T3-T4. The comparison group (low aggressive) included research subjects with Gleason sum &lt;7 AND Stage T1-T2 AND PSA &lt; 9 ng/ml. Odds ratios (OR) and 95% confidence intervals (95%CI) were calculated for high aggressive PCa for each SNP using logistic regression with adjustment for age and proportion of African ancestry. Associations were considered statistically significant at p&lt;0.05. A polygenic score based on a previous study of SNP predictors of serum 25-hydroxy-vitamin D levels was calculated utilizing SNPs in the GC, CYP24A1, CYP2R1, and NADSYN1 genes.

Results: Among African Americans, 21 SNPs were associated with PCa aggressiveness. The variant allele was associated negatively or positively with high aggressive PCa in eleven and ten SNPs, respectively. For example, two SNPs in the vitamin D binding protein gene known as GC, were inversely associated (rs222054: OR, 0.55, 95%CI, 0.38-0.80; and rs16847028: OR, 0.61, 95%CI, 0.39-0.94). Among European Americans, the variant allele was inversely associated with high aggressive PCa for four SNPs in three genes (CASRrs3863977; CYP24A1rs4809960; RXRArs1007971; and RXRArs3118526), and positively associated with high aggressive PCa for three SNPs in the CYP27B1 gene (rs703842, rs4646536, and rs10877013). There was no association between higher number of ‘low vitamin D’ alleles in the four SNPs that comprised the polygenic score and PCa aggressiveness for either race.

Conclusions: Polymorphisms in genes involved in vitamin D etabolism and activity, the vitamin D binding protein and calcium sensing receptor were associated with PCa aggressiveness, and there was no overlap in SNPs between race groups. Our ongoing work will examine interaction between polymorphisms of vitamin D-related genes and vitamin D metabolite levels on PCa aggressiveness.

Citation Format: Susan E. Steck, Anna Woloszynska-Read, Samuel Antwi, Hongmei Zhang, Lenore Arab, Elizabeth T.H. Fontham, James Mohler, L. Joseph Su, Feifei Xiao, Gary Smith, Donald Trump, Candace Johnson, Jeannette Bensen. SNPs in vitamin D-related genes are associated with prostate cancer aggressiveness in the North Carolina-Louisiana Prostate Cancer Project (PCaP). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 806.

NCCN Guidelines Insights: Prostate Cancer Early Detection, Version 2.2016

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Prostate Cancer Early Detection provide recommendations for prostate cancer screening in healthy men who have elected to participate in an early detection program. The NCCN Guidelines focus on minimizing unnecessary procedures and limiting the detection of indolent disease. These NCCN Guidelines Insights summarize the NCCN Prostate Cancer Early Detection Panel's most significant discussions for the 2016 guideline update, which included issues surrounding screening in high-risk populations (ie, African Americans, BRCA1/2 mutation carriers), approaches to refine patient selection for initial and repeat biopsies, and approaches to improve biopsy specificity.

Prostate cancer early detection, version 1.2014. Featured updates to the NCCN Guidelines

The NCCN Guidelines for Prostate Cancer Early Detection provide recommendations for men choosing to participate in an early detection program for prostate cancer. These NCCN Guidelines Insights highlight notable recent updates. Overall, the 2014 update represents a more streamlined and concise set of recommendations. The panel stratified the age ranges at which initiating testing for prostate cancer should be considered. Indications for biopsy include both a cutpoint and the use of multiple risk variables in combination. In addition to other biomarkers of specificity, the Prostate Health Index has been included to aid biopsy decisions in certain men, given recent FDA approvals.

Molecular characterization of enzalutamide-treated bone metastatic castration-resistant prostate cancer

BACKGROUND

Enzalutamide is a novel antiandrogen with proven efficacy in metastatic castration-resistant prostate cancer (mCRPC).

OBJECTIVE

To evaluate enzalutamide's effects on cancer and on androgens in blood and bone marrow, and associate these with clinical observations.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective phase 2 study, 60 patients with bone mCRPC received enzalutamide 160mg orally daily and had transilial bone marrow biopsies before treatment and at 8 wk of treatment.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Androgen signaling components (androgen receptor [AR], AR splice variant 7 (ARV7), v-ets avian erythroblastosis virus E26 oncogene homolog [ERG], cytochrome P450, family 17, subfamily A, polypeptide 1 [CYP17]) and molecules implicated in mCRPC progression (phospho-Met, phospho-Src, glucocorticoid receptor, Ki67) were assessed by immunohistochemistry; testosterone, cortisol, and androstenedione concentrations were assessed by liquid chromatography-tandem mass spectrometry; AR copy number was assessed by real-time polymerase chain reaction. Descriptive statistics were applied.

RESULTS AND LIMITATIONS

Median time to treatment discontinuation was 22 wk (95% confidence interval, 19.9-29.6). Twenty-two (37%) patients exhibited primary resistance to enzalutamide, discontinuing treatment within 4 mo. Maximal prostate-specific antigen (PSA) decline ≥ 50% and ≥ 90% occurred in 27 (45%) and 13 (22%) patients, respectively. Following 8 wk of treatment, bone marrow and circulating testosterone levels increased. Pretreatment tumor nuclear AR overexpression (> 75%) and CYP17 (> 10%) expression were associated with benefit (p = 0.018). AR subcellular localization shift from the nucleus was confirmed in eight paired samples (with PSA decline) of 23 evaluable paired samples. Presence of an ARV7 variant was associated with primary resistance to enzalutamide (p = 0.018). Limited patient numbers warrant further validation.

CONCLUSIONS

The observed subcellular shift of AR from the nucleus and increased testosterone concentration provide the first evidence in humans that enzalutamide suppresses AR signaling while inducing an adaptive feedback. Persistent androgen signaling in mCRPC was predictive of benefit and ARV7 was associated with primary resistance.

PATIENT SUMMARY

We report a first bone biopsy study in metastatic prostate cancer in humans that searched for predictors of outcome of enzalutamide therapy. Benefit is linked to a pretreatment androgen-signaling signature.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01091103.

A randomized trial of diet in men with early stage prostate cancer on active surveillance: rationale and design of the Men's Eating and Living (MEAL) Study (CALGB 70807 [Alliance])

BACKGROUND

Diet may substantially alter prostate cancer initiation and progression. However, large-scale clinical trials of diet modification have yet to be performed for prostate cancer. The Men's Eating and Living (MEAL) Study (CALGB 70807 [Alliance]) is investigating the effect of increased vegetable consumption on clinical progression in men with localized prostate cancer.

STUDY DESIGN

MEAL is a randomized, phase III clinical trial designed to test whether an intervention that increases vegetable intake will decrease the incidence of clinical progression in men with clinically localized prostate cancer on active surveillance. We are randomizing 464 patients to either a validated telephone-based diet counseling intervention or a control condition in which patients receive a published diet guideline. The intervention will continue for two years. The primary outcome variable is clinical progression defined by serum prostate-specific antigen (PSA) and pathological findings on follow-up prostate biopsy. Secondary outcome variables include incidence of surgical and non-surgical treatments for prostate cancer, prostate-cancer related patient anxiety and health-related quality of life.

CONCLUSION

The MEAL Study is assessing the effectiveness of a high-vegetable diet intervention for preventing clinical progression in men with localized prostate cancer on active surveillance.

Activity of abiraterone acetate in metastatic patients with castration-resistant prostate cancer (mCRPC) previously treated with ketoconazole: A prospective phase II study from the prostate cancer clinical trials consortium

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Background: Abiraterone acetate (AA), like ketoconazole (keto), inhibits CYP17, the rate-limiting enzyme in androgen biosynthesis. Since patients (pts) with prior keto treatment were excluded from the pivotal phase III AA trials, the utility of AA after keto is not well understood. This prospective study evaluated the efficacy of AA in pts who had received prior keto. Methods: Pts with progressive castration-resistant prostate cancer (mCRPC), prior keto therapy 28 days or more, and normal baseline organ function (including ACTH stimulation) tests were treated with AA 1,000 mg PO daily and prednisone 5 mg PO BID. Pts with prior chemotherapy were excluded. Serum androgen levels, including dehydroepiandrosterone (DHEA), were measured by liquid chromatography/mass spectroscopy (LC/MS) at baseline and during treatment for exploratory analyses. Radiographic progression-free survival (rPFS) was defined as freedom from: death, radiographic progression, or unequivocal clinical progression. Results: Forty two pts were enrolled. Median age was 71. Median prostate-specific antigen (PSA) was 47.5ng/dL. Median duration of prior keto was 38 weeks (range 5 to 207). Treatment with AA resulted in 30% or greater decline in PSA at 12 weeks in 20 pts (48%, 95% CI, 32-63%), and 50% or greater decline in PSA at 12 weeks in 16 pts (38%, 95% CI 24-54%). Median time to PSA progression (TTPP) was 16 weeks (range 4 to 64). Median rPFS was 24 weeks (range 1 to 88). Baseline serum DHEA levels were measured in 40 pts. Nine pts had DHEA less than the limit of quantitation (LOQ, 0.250ng/mL), and 31 pts had DHEA greater than or equal to LOQ. One pt with DHEA less than LOQ (1 out of 9, 11%, 95% CI 0.6-49%) had PSA decline 30% or more at 12 weeks, compared to 17 pts (17 out of 31, 55%, 95% CI 36-72%) with DHEA greater than or equal to LOQ (p=0.028). Median time to pain progression (TTPP) was 8 weeks (range 4 to 32) for pts with DHEA less than LOQ, compared to 18 weeks (range 4 to 64) for pts with DHEA greater than or equal to LOQ (p=0.012). Median rPFS was 12 weeks (range 4 to 24) for pts with DHEA less than LOQ, compared to 36 weeks (range 1 to 88) for pts with DHEA greater tha or equal to LOQ (p = 0.0006). Six pts remain on AA. Conclusions: A significant proportion of pts with prior keto exposure demonstrate clinical response to AA. DHEA levels via LC/MS merits further study as a predictive biomarker in pts treated with androgen synthesis inhibitors. Clinical trial information: NCT01199146.

A randomized pilot trial of dietary modification for the chemoprevention of noninvasive bladder cancer: the dietary intervention in bladder cancer study

Epidemiological data suggest robust associations of high vegetable intake with decreased risks of bladder cancer incidence and mortality, but translational prevention studies have yet to be conducted. We designed and tested a novel intervention to increase vegetable intake in patients with noninvasive bladder cancer. We randomized 48 patients aged 50 to 80 years with biopsy-proven noninvasive (Ta, T1, or carcinoma in situ) urothelial cell carcinoma to telephone- and Skype-based dietary counseling or a control condition that provided print materials only. The intervention behavioral goals promoted seven daily vegetable servings, with at least two of these as cruciferous vegetables. Outcome variables were self-reported diet and plasma carotenoid and 24-hour urinary isothiocyanate (ITC) concentrations. We used two-sample t tests to assess between-group differences at 6-month follow-up. After 6 months, intervention patients had higher daily intakes of vegetable juice (P = 0.02), total vegetables (P = 0.02), and cruciferous vegetables (P = 0.07); lower daily intakes of energy (P = 0.007), fat (P = 0.002) and energy from fat (P = 0.06); and higher plasma α-carotene concentrations (P = 0.03). Self-reported cruciferous vegetable intake correlated with urinary ITC concentrations at baseline (P < 0.001) and at 6 months (P = 0.03). Although urinary ITC concentrations increased in the intervention group and decreased in the control group, these changes did not attain between-group significance (P = 0.32). In patients with noninvasive bladder cancer, our novel intervention induced diet changes associated with protective effects against bladder cancer. These data show the feasibility of implementing therapeutic dietary modifications to prevent recurrent and progressive bladder cancer.

Role of 5α-reductase inhibitors in androgen-stimulated skin disorders

5α-reductase (5α-R) isozymes are ubiquitously expressed in human tissues. This enzyme family is composed of 3 members that perform several important biologic functions. 5α-R isozymes play an important role in benign prostate hyperplasia, prostate cancer, and androgen-stimulated skin disorders, which include androgenic alopecia, acne, and hirsutism. Discovery of 5α-R type 2 deficiency in 1974 sparked interest in development of pharmaceutical agents to inhibit 5α-R isozymes, and 2 such inhibitors are currently available for clinical use: finasteride and dutasteride. 5α-R inhibitors are US Food and Drug Administration (FDA)-approved for the treatment of benign prostate hyperplasia. Only finasteride is FDA-approved for treatment of male androgenic alopecia. This article reviews the pathophysiology of androgen-stimulated skin disorders and the key clinical trials using 5α-R inhibitors in the treatment of androgen-stimulated skin disorders.

Association of calcium channel blocker use with prostate cancer aggressiveness, progression-free survival, and overall survival

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Background: Epidemiological studies indicate that the use of calcium channel blockers (CCB) is inversely related to prostate cancer (PCa) incidence. The goal of this study was to examine the association between CCB use and PCa aggressiveness at the time of radical prostatectomy (RP) or outcome after RP. Methods: Information on medication use, PCa aggressiveness and outcome after RP was retrieved from a prospective database that contains clinical and follow-up (FU) data for all men that have undergone RP at the Department of Urology at Roswell Park Cancer Institute since 1992. The database was queried for anti-hypertensive medication use at the time of diagnosis for all patients with ≥ 1 year FU. Prostate cancer aggressiveness (risk status) and recurrence were defined using NCCN guideline definitions. Cox regression models were performed to compare the distribution of progression-free survival (PFS) and overall survival (OS) with adjustment for covariates. Chi-Square test was used to assess the relationship between CCB use and PCa aggressiveness. Results: 875 men were included in the study. At diagnosis, mean age was 60 (SD ± 7) years and mean serum PSA value was 7.4 (SD ±7.4) ng/ml. 48%, 37%, and 15% of patients had low risk, intermediate risk, or high risk PCa, respectively. 104 (12%) had a history of CCB use. CCB users and non-users were similar by PSA at diagnosis (p=0.97) and tumor aggressiveness (p=0.88). Patients taking CCB were more likely to be older (p=0.023), have a higher BMI (p=0.006) and use additional anti-hypertensive medications (p<0.01). Margin status after radical prostatectomy was similar (p=0.30) between the two groups. Median FU was 42 months. PFS (p=0.82, HR 95% CI: 0.63-1.44) and OS (p=0.72, HR 95% CI: 0.42-3.52) did not differ between the 2 groups. Adjusting for age and PCa aggressiveness did not alter the results observed for PFS (p=0.44, HR 95% CI: 0.62–1.41) and OS (p=0.50, HR 95% CI: 0.04-3.48). PCa aggressiveness was associated with PFS (p=0.001) in the multivariate model. Conclusions: CCB use does not affect PCa aggressiveness at time of diagnosis or improve PFS or OS.

The effect of BMI at time of surgery on long-term outcome after radical prostatectomy

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Background: Body mass index (BMI) at time of surgery was determined among 715 radical prostatectomy patients. The association of BMI with a range of treatment outcomes was considered. Methods: The associations of BMI at time of radical prostatectomy (RP) with disease stage and aggressiveness and long-term outcome were evaluated among 715 patients treated with RP at Roswell Park Cancer Institute between 1993 and 2005. Clinical and pathological aggressiveness indicators included clinical Gleason sum and tumor stage (2002 TNM), highest preoperative PSA, pathological Gleason sum and tumor stage (2002 TNM) and surgical margin status. Ten post-RP recurrence definitions were considered: 1) PSA ≥ 0.2 ng/ml; 2) PSA ≥ 0.4 ng/ml (with 1 confirming value); 3) 1 or more post RP treatments (ADT, radiation, chemotherapy); 4) PSA doubling time < 12 months; 5) PSA doubling time < 9 months; 6) PSA doubling time < 6 months; 7) NCCN definition of PSA failure; 8) AUA definition of PSA failure; 9) diagnosis of metastatic CaP; and 10) death from CaP. Results: Of the 715 men, 33 developed metastatic prostate cancer, and 17 died of prostate cancer. 246 men had BMI ≥ 30. BMI was not significantly associated with clinical or pathological aggressiveness criteria. These analyses showed that there is a trend towards higher risk of the development of metastasis or death for men with BMI ≥ 30, although the association with high BMI and these failure types is not significant. With adjustment for the most significant tumor aggressiveness features (clinical Gleason sum, pathological tumor stage, pathological Gleason sum, and surgical margin status) in proportional hazards regression, men with BMI ≥ 30 had consistently lower risk for all definitions of recurrence except metastasis and death, although no hazard ratios were significant. In contrast, men with higher BMIs had higher risk for metastasis and death from prostate cancer, although neither association is statistically significant. Conclusions: Men with higher BMIs show similar to slightly reduced risk for PSA-based recurrence definitions. Men with higher BMIs had slightly higher risk, though not significant, for metastasis and death. These results seem to support theories that PSA is diluted in men with higher BMIs.

Abstract 2696: Modulation of intracrine androgen signaling in bone metastatic castrate resistant prostate cancer (bmCRPC) by MDV3100

Background Androgen signaling is a central driver in CRPC. We performed a study to determine the effect of the antiandrogen MDV 3100 on bone marrow infiltrating CRPC. Methods From February 2010 to June 2011, we performed an open-label, observational study of 60 bmCRPC patients (pts), who underwent transilial bone marrow biopsy (BMB) at baseline and 8 weeks of treatment. Pts received MDV3100 160mg orally once daily. The primary objective was to evaluate androgen signaling in bone marrow infiltrating cancer and testosterone in blood (BT) and bone marrow (BMT) and correlate findings with clinical observations. Androgen receptor (AR), CYP17 and phospho Src (pSrc) expression were assessed by immunohistochemistry, and BT and BMT by liquid chromatography mass spectrometry. Findings Maximal PSA decline of Δ50% occurred in 29 (48%) of 60 pts, and α90% in 13 (22%). Tumor involvement in BMB was detected in 28 (47%) pretreatment BMBs. Paired tumor infiltrated BMBs were found in 23 (38%) pts. Pretreatment androgen signaling and pSrc tumor expression is shown in Table 1. Pretreatment intense nuclear AR expression combined with α10% CYP17 tumor expression or increased BMT correlate with Δ50% PSA decline (p value 0.02). AR subcellular localization shift from dominant nuclear to cytoplasmic correlate with Δ50% PSA decline (p value 0.05). Increased pretreatment p-Src expression is associated with lack of PSA decline (p value 0.002). Increase in BMT and BT is observed after 8 weeks of MDV3100. (Mean Pretreatment BMT 0.03 ng/ml, Wk8 BMT 0.04 in 33pts, p value 0.0009) (Pretreatment BT 0.05, wk8 BT 0.066 in 37 pts, p value 0.0001) Interpretation Pretreatment expression profile is consistent with persistent androgen signaling in bmCRPC. MDV3100 induces ‘pharmacodynamic’ changes in Androgen Signaling. AR changes likely account for the reported therapeutic effect of MDV3100. These data prompt exploratory combinations of MDV3100 with Androgen Biosynthesis Inhibitors and src inhibitors.

Abstract 3637: Loss of prostate derived Ets (E-twenty six) transcription factor (PDEF) predicts patients at the highest risk of metastatic prostate cancer

PSA has ability to detect prostate cancer (CaP) at an early stage, but many CaP tumors are slow to progress, and many patients are overtreated for a disease that will not become life-threatening. Since there remains no reliable way to distinguish indolent from aggressive disease, doctors who advise and patients on active surveillance worry about progression to incurable disease. Therefore, new prognostic tools must be developed to identify patients with potentially metastatic, life threatening CaP. Prostate derived Ets transcription factor (PDEF) has shown to be a master negative regulator of transcriptional networks controlling migration and invasion in many cancer tissues, including CaP. Therefore we studied the expression of PDEF in radical prostatectomy specimens to determine retrospectively whether PDEF expression is predictive of clinical outcome. Patients’ tumor PDEF expression was determined by immunohistochemical staining of a 724 patient tissue microarray (TMA). CaP patients were stratified into groups based on PDEF expression (high, mid, low, null) and a Cox proportional hazards model was used to compare clinical outcomes. Univariate analysis showed that loss of PDEF expression significantly increased risk of metastatic disease (HR = 5.38, PDEF mid; to HR = 43.48, PDEF null; p=0.0059), although it did not correlate with incidence of biochemical failure detected using the American Urological Association (AUA) or National Comprehensive Cancer Network (NCCN) definitions. This result was confirmed in the Kaplan-Meier survival analysis that showed that patients whose CaP were PDEF low/null had significantly shorter metastases-free survival (p=0.0151). Multivariate analysis also demonstrated CaP with low/null PDEF expression were associated with increased risk of developing metastatic disease (HR = 6.21/10.53), although it was not statistically significant, in part due to the low incidence of patients with metastatic disease in the TMA. Therefore, we studied PDEF and vimentin (stem-like marker, repressed by PDEF) tumor expression in a cohort of patients matched for Gleason score, stage, age, and follow-up who developed metastatic disease versus those who did not. Patients that developed metastatic disease had a significantly lower PDEF (3.9 vs 1.7, p&lt;0.0001) and higher vimentin (0.43 vs. 4.1, p&lt;0.0001) expression compared to matched controls. We propose that intact PDEF expression in CaP can be used to distinguish patients who are suitable for active surveillance from those who require aggressive treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3637. doi:1538-7445.AM2012-3637

Abstract A2: A Study of the effects of MDV3100 in the tumor microenvironment of bone metastatic castrate resistant prostate cancer (bmCRPC)

Background: Androgen signaling remains a central driver in castrate-resistant prostate cancer. We performed a study to determine the effect of the antiandrogen MDV 3100 on bone marrow infiltrating CRPC.

Methods: From February 2010 to June 2011, we performed an open-label, observational study of 60 bmCRPC patients (pts), who underwent transilial bone marrow biopsy (BMB) at baseline, 8 weeks and end of study. Pts received MDV3100 160mg orally once daily. The primary objective was to evaluate androgen signaling in bone marrow infiltrating cancer and testosterone in blood (BT) and bone marrow (BMT) and correlate findings with clinical observations. Androgen receptor (AR) c-terminus n-terminus, AR Variant 7 (ARV7), ERG, CYP17, phospho Src (pSrc), expression and mitotic index (Ki67 ) were assessed by immunohistochemistry, AR copy number by qPCR and BT and BMT by liquid chromatography mass spectrometry.

Initial Findings: Maximal PSA decline of ≥50% occurred in 29 (48%) of 60 pts, and ≥90% in 13 (22%). Tumor involvement in BMB was detected in 28 (47%) pretreatment BMBs. Paired tumor infiltrated BMBs were found in 23 (38%) pts. Increased androgen receptor expression (n-terminal antibody used for IHC) was observed at pretreatment with heterogeneous CYP17 and pSrc extent of expression.

Pretreatment intense nuclear AR expression combined with ≥10% CYP17 tumor expression or increased BMT correlate with ≥50% PSA decline (p value 0.02). AR subcellular localization shift from dominant nuclear to cytoplasmic and regression of bone marrow tumor infiltration correlate with ≥50% PSA decline (p value 0.05). Increased pretreatment p-Src expression is associated with lack of PSA decline (p value 0.002). Increase in BMT and BT is observed after 8 weeks of MDV3100 (mean pretreatment BMT 0.026 ng/ml, Wk8 BMT 0.04 in 33pts, p value 0.0001) (pretreatment BT 0.041, wk8 BT 0.066 in 37 pts, p value &lt;0.0001).

Interpretation: Pretreatment expression profile is consistent with persistent androgen signaling in bmCRPC. MDV3100 induces pharmacodynamic changes in androgen signaling. AR changes likely account for the reported therapeutic effect of MDV3100. These data prompt exploratory combinations of MDV3100 with androgen biosynthesis inhibitors and src inhibitors.

Citation Format: Eleni Efstathiou, Patricia Troncoso, James Mohler, Christopher J. Logothetis, Mark Titus, Dimitra Tsavachidou, Sijin Wen, Anh Hoang, Robynne Ashe, Maria Karlou, Craig Berman. A study of the effects of MDV3100 in the tumor microenvironment of bone metastatic castrate-resistant prostate cancer (bmCRPC) [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr A2.