Citations

255 Background: In a prior study, we found that 8 single nucleotide polymorphisms (SNPs) from 4 candidate hormone-related genes (JAK2, TRMT11, NKX3-1 and HSD17B12) were associated with overall survival (OS) in CRPC stage in a North American cohort of 519 subjects. We attempt to replicate these findings in an independent cohort of Portuguese patients. Methods: A hundred and forty CRPC stage patients in the new cohort were genotyped fort he candidate SNPs. The primary endpoint was overall survival (OS), defined as time from development of CRPC to death. For SNP level results we estimated hazard ratios (HR) and 95% confidence intervals (CI) under the dominant allele model using Cox regression and adjusted for age and Gleason score (GS). Results: The median age of the Portuguese cohort was 69 years (range 53-84). The GS distribution was 48% subjects with GS≥8; 35% with GS=7 and 17% with GS<7. Median time from castration resistance to death for the cohort was 2.2 years (IQ range: 0.8-3.4, 93 deaths). One of the 3 SNPs (rs2295005; C>G; MAF = 0.16) in the TRMT11gene was associated with OS after adjustment for age and GS: (dominant model p=0.05, HR=0.56; 95 CI=0.31-1.00). No other SNP was observed to have statistical significance with OS (Table 1). Conclusions: Variation in the TRMT11 gene is significantly associated with overall survival in patients with CRPC and warrants further validation as a potential prognostic biomarker. [Table: see text]

249 Background: Evaluating tumor specific pathologic and genetic profiles in mCRPC stage is difficult due to the limited availability of mCRPC tissue. We describe findings from a prospective cohort study performed to obtain concomitant histopathology and genetic information in mCRPC. Methods: Patients with mCRPC initiating abiraterone acetate therapy underwent 2 serial (3 months apart) metastatic (met) site needle core biopsies (NCB1/2). Bone lesions were biopsied using 11-13G core needles and 18G core biopsy devices were used for non-osseous masses. Up to 4 cores were obtained at each biopsy with the 1st core (S1) sent for DNA sequencing, the 2nd (S2) for RNA sequencing, and the 3rd/4th (X3, X4) submitted for xenograft implantation. From each, 1-2 mm segments were separated and formalin-fixed for histopathologic examination (HPE). Results: A total of 54 patients, enrolled between June 2013 and July 2014, underwent 94 NCB (54 NCB1, 40 NCB2), rendering a total of 259 samples (94 S1; 75 S2; 59 X3 and 31 X4) of which 85 (32%) were positive (pos) for tumor by HPE. Positivity for tumor in S1, S2, X3, and X4 cores was 42%, 33%, 22%, and 19%, respectively. At least one core pos for met tumor was observed in 62% NCB1 and 52% NCB2 (overall 52/94; 56%). Met sites biopsied include bone (71), lymph nodes (18), liver (3), penile (1) and pelvic (1) soft tissues. HPE revealed met adenocarcinoma in 44/52, and poorly differentiated carcinoma in 8/52. Gleason grade applied to the met ranged from 3+4 to 5+5. 45/85 pos samples (53%) had > 50% tumor cellularity. Pos NCB in bone lesions was observed in 23/71 (32%), compared to 17/23 (73%) of non-bone sites (p=.0004). 85 S1 samples yielded DNA material, of which 66 (77%) had ≥10% tumoral DNA. 24 cases with negative HPE had ≥10% tumoral DNA; 7 cases with pos HPE had <10 tumoral DNA. In all, 76/94 (81%) NCB yielded tumor material either by HPE or DNA analysis. Conclusions: NCB of mCRPC is feasible and provides adequate tissue for pursuing HPE and sequencing studies. HPE of extracted material correlates with DNA sequencing data and provides complementary information on tumor features. Bone lesions yield significantly less tumoral material than non-osseous sites.

209 Background: Predictive markers of response to AA are not known. In a prior study, we found that 8 single nucleotide polymorphisms (SNPs) from 4 candidate hormone-related genes (JAK2, TRMT11, NKX3-1 and HSD17B12) were associated with response to AA in HSPC in a North American cohort of 519 subjects. We attempt to replicate these findings in a cohort of Portuguese patients. Methods: The Portuguese cohort consisted of 308 HSPC patients, and the primary endpoint was time to AA failure, defined as time from initiating continuous AA to two serial PSA increases over the nadir, initiation of chemotherapy for progressive disease, or clinical or imaging based progression, whichever came first. For each SNP, we calculated hazard ratios (HRs) and 95% confidence intervals (CI) for time to AA failure using a recessive model with adjustment for Gleason score (GS). Results: The median age of the Portuguese cohort was 69 years (range 43, 85). The GS distribution was 35% subjects with GS≥8; 35% with GS=7 and 30% with GS<7. Median time to AA failure for the cohort was 1.8 years (IQ range: 0.3, 3.6). Association of each SNP with time to AA failure is shown in the Table. None of the SNPs replicated. However, there was a suggestive inverse association for rs10503733 (NKX3.1) with time to AA failure (P=0.07). Conclusions: While we were not able to replicate our initial findings, there was an unexpected association with rs10503733 (NKX3.1 gene) that may warrant additional clinical validation. [Table: see text]

190 Background: It is not known if biopsy of CRPC stage metastases alters CTC results. We evaluated pre & post biopsy CTC counts in a prospective cohort undergoing pre-chemotherapy abiraterone acetate/prednisone (AA/P). Methods: CTC enumeration was performed on 7.5mL blood using the FDA cleared immunomagnetic/immunofluorescence assay (CellSearch). Time of blood draw for CTC counts pre/post biopsy was recorded for each biopsy. Biopsies were performed using 11/13 gauge core biopsy device for bone lesions and 18 gauge core needle biopsy device for soft tissue/nodal metastases. All patients (pts) underwent two serial biopsies 3 months apart. Change in CTC counts pre/post biopsy for visits 1 and 2 were evaluated using Wilcoxon signed rank test (significance at p<0.05). Differences in CTC count change (visit1) pre/post biopsy based on metastatic site (skeletal vs. non-skeletal) was compared using Wilcoxon rank-sum test. Results: Median age of the cohort was 74 years (IQR: 68-78); median PSA at V1 was 16.4 ng/ml (IQR: 6.4-87.6); at V2 was 11.5 ng/ml (IQR: 1.8-23.7). Of 59 pts undergoing biopsies 42 were in bone and 17 in nodal/soft tissue masses. At V1, pre/post biopsy CTC counts were measured on 50 and 49 pts, respectively; at V2, pre/post CTC counts were measured on 43 and 36 pts. High volume metastatic disease at V1 was observed in 67.8 % of all pts. Table lists CTC counts and time of collection pre/post biopsy for both visits. Mean change in pre/post biopsy CTC counts for skeletal sites was 0.7 (range: -12 to 64) compared to 12.1 (range: -21 to 13) for non-skeletal sites (p=0.23). Conclusions: An increase in mean CTC counts after biopsy of CRPC metastases was observed. No significant differences in change of CTC counts based on site biopsied (skeletal versus non-skeletal) was noted. Correlation with clinical outcomes is on-going. Clinical trial information: NCT# 01953640. [Table: see text]

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]

256 Background: B7-H3 (CD276), part of the B7 superfamily, has been shown to play an immunomodulatory role, however its regulation, receptor and mechanism of action remain unclear. Protein levels of B7-H3 have been previously shown to relate to prostate cancer outcomes and currently, humanized monoclonal antibodies are being developed for clinical use (MGA271, Macrogenics). Here we use genomic expression data to examine the relationship of B7-H3 to prostate cancer outcomes and molecular subtypes. Methods: Prostatectomy tissue from 905 patients were profiled using the Affymetrix HuEx 1.0 ST microarray. Kruskal-Wallis tests were used to identify significant associations of B7-H3 expression with clinico-pathologic variables, and survival analysis were used to evaluate the prognostic value of B7-H3. Pearson’s correlation analyses were also performed to assess the relationship of B7-H3 expression with molecular subtypes and individual transcripts. Androgen receptor (AR) occupancy of promoter regions was derived in silico from chromosomal immune-precipitation (ChIP) data. Results: B7-H3 expression was positively associated with Gleason score (p < 0.01) and tumor stage (p < 0.01). High B7-H3 expression also correlated with the development of metastasis and prostate cancer specific mortality (HR of 3.4 and 2.4 respectively, p < 0.05 for both), but this was not significant on multi-variable analysis. B7-H3 was positively associated with ERG+ disease (n = 670, r = 0.85, p < 0.05) and AR expression (n = 670, r = 0.46, p < 0.001). B7-H3 was found to be one of the most correlated genes with AR (95th percentile) and ChIP analysis revealed AR binding upstream of B7-H3, suggesting potential androgen dependent regulation. Conclusions: B7-H3 expression correlates with high Gleason grade and advanced prostate cancer stage with higher quartiles of expression portending poor oncologic outcomes in two independent prostatectomy cohorts. B7-H3 expression appears to relate to the androgen receptor.

255 Background: The purpose of this study was to identify site-specific recurrence patterns for patients (pts) with biochemical recurrence (BCR) after prostatectomy (RP) using C-11 Choline PET/CT (C11Ch) and 3T pelvic MRI with endorectal coil (pMRI). Methods: Between 2008 and 2006, 2,466 men underwent C11Ch and pMRI for BCR after RP. From this cohort, we identified 261 pts who received no adjuvant or salvage therapy (androgen deprivation or radiation). Suspected radiographic relapse was confirmed by biopsy (46%) or progression/response to treatment in concordance with subsequent rise/decline in PSA (54%). Results: Of the 261 men evaluated, 202 (75%) had positive pMRI, C11Ch or both. Seventy nine (39%), 105 (52%) and 18 (9%) pts had high, intermediate, and low risk CaP, respectively at RP. Median PSA at the time of positive scan was 2.3 ng/mL, with a median time from BCR to radiographic disease identification of 15 months. Of these 202 men, 67 (33%) harbored prostate fossa recurrence only, 44 (22%) had a combination of local and metastatic disease and 91 (45%) had metastatic disease without local recurrence. Forty (20%) pts had pelvic nodal recurrence only and 18 (9%) had perirectal nodal involvement. Median PSA for pts with local only recurrence, distant metastases only, and local + distant disease was 2.3, 2.7 and 2.2 ng/mL, respectively, with a median interval from BCR to positive scan of 16.7, 7.9 and 11 months. Imaging revealed that 33% to 66% of our cohort would have all sites of disease treated by salvage RT depending on the extent of the treatment field Conclusions: C11Ch and pMRI were used to identify recurrence patterns in pts with BCR after RP only. At median PSA of 2.3 ng/ml, our study demonstrates a low rate of local-only recurrence, higher than anticipated frequency of metastatic recurrence with peak frequency within the pelvic lymph nodes, and substantial perirectal recurrences. Despite the high rates of distant recurrences, 2/3 of our cohort had their disease limited to the pelvis and could be potential candidates for local therapies, including salvage radiation.