Costello, Brian A.

174 Background: AA/P is an FDA approved treatment for mCRPC. Since markers of early resistance to AA/P are unknown, we report initial findings of androgen receptor (AR) based associations with short term (12 week) progression on AA/P. Methods: mCRPC stage patients (pts) initiating pre-chemotherapy AA/P underwent metastatic site biopsies at baseline (pre AA/P) and after 12 weeks. Baseline somatic whole exome DNA, tumor gene expression for AR full length (ARFL), AR splice variant 7 (ARV7) and ARV7/ARFL ratios were compared in progessors versus non-progressors. Progression at or within 12 weeks of AA/P therapy was defined as death or disease progression by PCWG2 “composite progression (CP)” and/or “radiographic progression” endpoints. Wilcoxon rank-sum tests were used to test for differences in the two groups for comparing ARFL, ARV7 expressions and ARV7/ARFL ratios and chi square tests were used for differences in copy number variation. Results: Between 1/2013 and 6/2014, 59 pts were enrolled of which 44 have disease assessment data at the12-week time point. CP was observed in 17/44 patients. DNA seq and clinical data was available for 42/44 pts. Using radiographic progression at 12 weeks, AR Amplification/Gain was observed in 20/26 non-progressors (13 with Amplification) and in 9/16 progressors (P-value = 0.19; OR 2.5). ARFL and ARV7 gene expressions in both groups is provided in table. Conclusions: A trend towards higher ARV7/ARFL gene expression ratio in metastases was observed with early progression on AA/P. AR gain/amplification is observed less often in pts with early progression. Validation of these findings is on-going in this prospective trial. Clinical trial information: NCT# 01953640. [Table: see text]

617 Background: Over the past decade, seven agents were approved for metastatic renal cell carcinoma (mRCC) leading to a rapidly evolving clinical landscape. Clinical trials addressing treatment efficacy, sequencing, and other questions may continue to impact management decisions. Furthermore, our prior retrospective experience indicates a significant proportion of pts may not receive systemic therapy in the first year after diagnosis with metastatic disease. This analysis describes contemporary patterns of care in the first 109 real world pts enrolled in a multicenter, prospective, observational registry. Methods: MaRCC Registry will enroll 500 pts from up to 60 US academic (ACAD) and community (COMM) sites with ~2 years of recruitment and ≥ 3 years of follow-up. Key inclusion criteria are age ≥ 18 years and diagnosis of mRCC with no prior systemic therapy (STx) for mRCC at study entry. Pts currently not on STx but who are being observed are permitted. Key endpoints include descriptive characteristics of treatments (e.g. treatment agents, sequence, duration, reasons for therapy choice and discontinuation), treatment effectiveness (e.g. overall response rate, progression free survival, overall survival), quality of life (PROs), medication adherence, and health resource utilization. Results: At data cutoff, 105 pts have been accrued with known STx status; median age 64 (Q1-3 range, 56-70); 66% male; 75% ACAD; 87% clear cell histology; and 31% stage IV at diagnosis. Initial management strategies are shown in the table. The initial management decision after accrual was to defer systemic therapy (Def STx) in 40% (N=44). In ACAD and COMM sites, Def STx percentages were 38% and 48% respectively. Baseline demographics and clinical characteristics were not notably different between Def STx pts and those treated with STx. Conclusions: In our prospective registry, we have identified a large percentage of pts who initially received Def STx. In the context of contemporary pts undergoing investigational and standard of care STx, we will describe the management and outcomes of the Def STx population. [Table: see text]

563 Background: Clinical trials mRCC pts are different from real world pts, resulting in bias in the literature. The MaRCC Registry is designed to survey questions not asked in tri als, such as why physicians make certain management decisions. This analysis describes reasons for physician treatment (tx) selection in the first 109 real world pts enrolled in a multicenter, prospective, observational registry. Methods: MaRCC Registry will enroll 500 pts from up to 60 US academic (ACAD) and community (COMM) sites with ~2 years of recruitment and ≥ 3 years of follow-up. Key inclusion criteria are age ≥ 18 years and diagnosis of mRCC with no prior systemic therapy (STx) for mRCC at study entry. Pts currently not on STx but who are being observed are permitted. Key endpoints include descriptive characteristics of txs, tx and patient outcomes, medication adherence, and health resource utilization. Results: At data cutoff, 105 pts have been accrued with known STx status; median age 64 (Q1-3 range, 56-70); 66% male; 75% ACAD; 87% clear cell histology; and 31% stage IV at diagnosis. Initial management decision was: 40% deferred systemic therapy (DSTx), 22% pazopanib, 18% clinical trial, 10% sunitinib, and 6% other. Among STx pts (N = 61), the most common categories for therapy choice as selected by providers were likelihood of clinical benefit (41%) followed by pt characteristics (30%). Within the clinical benefit category, the most common reason was OS/PFS (31%). Within the pt characteristic category the most common reasons included performance status/frailty (12%) or prognostic factors (12%). Common reasons for DSTx pts (N = 44) were active surveillance (AS) with disease present (39%), AS without disease present following a procedure (11%), or local therapy (7%). ACAD sites had higher percentages of pts with DSTx undergoing AS with disease present and local therapy. Conclusions: This is the first report describing factors driving physician decision making in management of mRCC. Management choices are not captured in other prospective or retrospective studies. Early experience suggests that clinical benefit and pt characteristics were common reasons for initial STx. Side effect profile rarely determined initial STx selection.

313 Background: We evaluated variation in candidate genes implicated in either initiation or progression of prostate cancer with survival in CRPC stage. Methods: Germline DNA was extracted from peripheral blood mononuclear cells of CRPC patients enrolled in a clinically annotated registry. Fourteen candidate genes were tagged using single nucleotide polymorphisms (SNPs) from HapMap with minor allele frequency of > 5%. The primary endpoint was overall survival (OS), defined as time from development of CRPC to death. Principal component analysis was used for gene levels tests of significance. For SNP level results the per allele hazard ratios (HR) and 95% confidence intervals (CI) under the additive allele model using Cox regression adjusted for age at CRCP and Gleason score (GS) were used. Results: Two hundred and forty five CRPC patients who met the criteria of having adequate DNA were genotyped (14 genes, 84 SNPs). The median age of the cohort was 69 years (range 43-93). The GS distribution was 55% with GS≥8, 32% with GS = 7 and 13% with GS < 7 or unknown. Median time from castration resistance to death for the cohort was 2.67 years (IQ range: 1.6-4.07, 144 deaths). At the gene level JAK2 was detected to be associated with OS. Six of 18 JAK2 SNPs were associated with OS after adjustment for age and GS as well as pruning of SNPs in high linkage disequilibrium with each other (see table). In our multivariate model including age, GS, rs2149556, and rs4372063, the adjusted HRs for rs2149556 and rs4372063 were 0.67 (95% CI 0.38-1.18) and 2.17 (95% CI 1.25-3.76), respectively. The protective effect of rs2149556 appears after adjusting for the presence of minor alleles for rs4372063 in this dataset. Conclusions: Germline variation in the JAK2gene is associated with survival in CRPC stage and warrants further validation as a potential prognostic biomarker. [Table: see text]

237 Background: AA/P is an approved treatment for mCRPC but there are no known predictive markers of response or resistance. We conducted a prospective trial to evaluate if Androgen Receptor (AR) & AR-variant (ARV) expression in tissue metastases can predict resistance to AA/P. Methods: mCRPC stage patients (pts) initiating pre-chemo AA/P underwent metastatic site biopsies prior to (pre-AA/P) and after 12 weeks of treatment. Composite progression at 12 weeks, (primary endpoint) was evaluated with PSA, RECIST, bone scan and symptoms (per PCWG2). mRNA expressions of pre-AA/P ARFL, ARV3, ARV7, ARV9, ARV23, ARV45, four cell cycle division genes, Chromogranin-A (CHGA) together with PSA/testosterone levels, Gleason Score (GS) at initial diagnosis; high versus low volume disease; time from starting hormone therapy to mCRPC stage and serum CHGA levels were evaluated using a logistic regression model for predicting resistance at 12 weeks of therapy. A final multivariate model fitted only those factors thought to be clinically relevant or with an entry threshold of p ≤ 0.3 in univariate analysis. Results: Between 6/2013 & 3/2015, 82 pts were enrolled of which 52 had complete mRNA expression & disease assessment data at the12-week time point for analysis. Median age of the cohort was 72.5 yrs (IQR: 68.5-78); median pre-AA/P PSA was 18 ng/ml (IQR: 8.1- 46.6); GS distribution at initial diagnosis for GS 2-6; 7; 8-10 was 11; 14; 27 respectively. Progression was observed in 21/52 pts after 12 weeks. At the univariate level elevated pre-AA/P expression of ARV3 (p = 0.08), ARV7 (p = 0.26), ARV9 (p = 0.04), and cell division cycle gene CDC45 (p = 0.19) along with GS at diagnosis (p = 0.29) met the threshold for inclusion into multivariate analysis. Elevated expression of pre-therapy ARV9 in metastases alone was associated with progression at 12 weeks (OR: 3.9; CI 1.07 – 14.16; C-Index: 0.63). The 12-week biopsy of pts with progression had increased ARV9 mRNA expression compared to pts responding at 12 weeks (p = 0.14). Conclusions: Increased ARV9 mRNA expression in metastases is associated with early resistance to AA/P. This observation will need further validation in comparable datasets. Clinical trial information: NCT #0195364.

44 Background: We investigated the association of germline genetic variation in hormone biosynthesis and metabolism genes with prostate cancer specific mortality in a cohort of advanced prostate cancer patients. Methods: We successfully genotyped 852 single nucleotide polymorphisms (SNPs) from 97 genes in a cohort of 267 advanced prostate cancer patients at the time of progression to castration recurrence (CRPC) during on-going androgen ablation. Tagging SNPs with minor allele frequency (MAF) of >5% and r2 ≥0.8 were selected from HapMap, NIEHS and Seattle SNP databases. Medical records were queried for cause of death. The primary endpoint of time to prostate cancer specific mortality (PCSM), was pre-defined as time from development of CRPC to death from prostate cancer progression. Principle components analysis was used for gene-levels tests, and to account for multiple testing, we calculated the false discovery rate (FDR). For SNP level results, hazard ratios (HR) and 95% confidence intervals (CI) were estimated using cox regression. Results: The median age of the cohort was 72 years at CRPC. 43% had a Gleason score (GS)=8-10, 33% a GS=7, and 24% a GS<7. After a median follow-up of 1.8 years (IQ range: 0.8–3.3 years), 139 patients died, of which 107 were due to prostate cancer progression. In unadjusted gene level analyses, UGT1A7 (p=0.0059; FDR=0.19), UGT1A10 (p=0.0017; FDR=0.17) and UGT1A3 (p=0.0037; FDR=0.18) were associated with PCSM. After adjusting for age and GS, SNPs strongly associated with PCSM are listed in the Table . Conclusions: Variation in UGT genes involved in hormone metabolism yield prognostic information in CRPC. Further validation is needed to develop these as prognostic biomarkers. [Table: see text] No significant financial relationships to disclose.

14 Background: We evaluated the association of germline variation in genes regulating hormonal pathways with duration of treatment response in prostate cancer patients receiving ADT, focusing on genes in the androgen biosynthesis (the C4 Δ; C5 Δ; C21 CYP pathways and the alternate “backdoor pathway”) and metabolism pathways. Methods: We successfully genotyped 747 single nucleotide polymorphisms (SNPs) from 84 genes in a cohort of 304 patients with advanced prostate cancer who progressed on ADT. Tagging SNPs with a minor allele frequency (MAF) of >5% and r2 ≥0.8 were selected from HapMap, NIEHS and Seattle SNP databases. The primary endpoint was time to ADT failure, and we conducted a gene-level test (principal components), along with individual SNP level tests adjusted for patient age and Gleason score. To account for multiple testing, we calculated the false discovery rate (FDR), and FDRs of 0.10 were considered noteworthy. Results: The median age of the cohort at ADT failure was 72 years (range 65-78 years), and the overall median time to ADT failure was 3.21 years (IQ [25-75]: 1.54-6.20 years). At the gene level, TRMT11 (tRNA methyltransferase 11 homologue) showed the strongest association with time to ADT failure (p<0.0008; adjusted p-value for FDR-0.068). Two of four TRMT11 tag SNPs were associated with time to ADT failure. The first was the intronic SNP rs1268121 (A>G) with a MAF of 15%, for which there was a positive association of median time to ADT failure with the number of variant alleles (p=0.023): 3.1 years for 0, 4.1 years for 1, and 5.9 years for 2 variant alleles. The second was the SNP rs6900796 (A>G) in the 3' untranscribed region with a MAF of 49%, for which the median time to ADT failure was 2.6 years for 0, 2.5 years for 1, and 3.8 years for 2 variant alleles (p=0.023). Four additional genes showed an association with ADT response at the p<0.10 level, including LOC390956, PRMT3, SLC7A6OS, and WBSCR22, although all FDRs were >0.95. Conclusions: Variation in TRMT11 was associated with time to ADT failure. Confirmation of these findings in an independent cohort is needed. No significant financial relationships to disclose.

Objectives To describe the clinicopathological features associated with increased risk of renal fossa recurrence ( RFR ) after radical nephrectomy ( RN ) and to describe the prognostic features associated with cancer‐specific survival ( CSS ) among patients with RFR treated with primary locally directed therapy, systemically directed therapy or expectant management. Patients and Methods The records of 2 502 patients treated with RN for unilateral, sporadic, localized renal cell carcinoma ( RCC ) between 1970 and 2006 were reviewed. CSS after RFR was estimated using the Kaplan–Meier method. Associations with the development of RFR and CSS after RFR were evaluated using Cox proportional hazards regression models. Results A total of 33 (1.3%) patients developed isolated RFR ( iRFR ) and 30 (1.2%) patients developed RFR in the setting of synchronous metastases after RN (study cohort, N = 63). The median follow‐up for the series was 9.0 years after RN and 6.0 years after RFR diagnosis. On multivariable analysis, advanced pathological stage ( pT 2: hazard ratio [ HR ] 4.36, P = 0.004; pT 3/4: HR 4.39, P = 0.003) and coagulative necrosis ( HR 2.71, P = 0.006) were independently associated with increased risk of iRFR . The median time to recurrence was 1.5 years after RN among the 33 patients with iRFR , and 1.4 years among all patients. Overall, the median CSS was 2.5 years after diagnosis of iRFR , 1.3 years after RFR in the setting of synchronous metastases, and 2.2 years overall. After primary locally directed therapy (surgery, ablation or radiation), systemic therapy or expectant management, the 3‐year CSS rates among patients with iRFR were 63%, 50% and 13% ( P = 0.001) and were 64%, 50% and 28% ( P = 0.006) among all patients, respectively. On multivariable analysis, when compared with observation, locally directed therapies were associated with a significantly decreased risk of death from RCC ( HR 0.26, P < 0.001). Conclusions Renal fossa recurrence is a rare event after RN for RCC and portends a poor prognosis, even in the absence of synchronous metastases. Development of iRFR is associated with advanced stage and aggressive tumour biology. Patients who underwent primary locally directed therapy had superior CSS compared with those treated with expectant management, supporting the use of aggressive local treatment in carefully selected patients with RFR . Future research is needed to determine the optimum role and sequencing of combined therapy in patients with this rare entity.