Citations

168 Background: Androgens and estrogens have been shown to play an important role in normal prostate development and function as well as carcinogenesis and development of the castration resistant phenotype of disease. The aim of this study was to evaluate the effect of a simultaneous administration of an androgen receptor antagonist (bicalutamide) and a selective estrogen receptor modulator (raloxifene) on both androgen sensitive and androgen insensitive prostate cancer cell lines. Methods: Experiments were performed on LNCaP, PC3 and DU145 cell lines. Western blot was utilized for the identification of androgen and estrogen receptors (a andb) in the cell lines. Drug concentrations required to achieve IC 50 were obtained using the MTT assay; such concentrations were identified for the drugs individually and when used in combination. The effect of the drugs on apoptosis was assessed using flow cytometry. Results: Results of the IC 50 for the drugs alone and in combination by each cell line are shown in the table. An enhanced effect was observed when the drugs were used in combination in all the cell lines. It was evident that the combination of the drugs decreased the total drug required to achieve the IC50 decreases considerably. Apoptosis rates were also affected by the simultaneous administration of bicalutamide and raloxifene. The synergistic effect of the combination was reflected in the increase of the apoptosis rate in all cell lines. Conclusions: The simultaneous administration of bicalutamide and raloxifene has a synergistic effect on cell death and apoptosis of DU145, PC3 and LNCaP cell lines. The pathway(s) responsible for this observation may be independent of the androgen receptor as both AR negative cell lines were still affected by the combination over the SERM alone. [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.

106 Background: Some patients with lymph node metastases experience prolonged survival following radical prostatectomy. The purpose of this study was to determine the outcome of patients with clinically suspicious lymph nodes on preoperative imaging who underwent radical prostatectomy and lymphadenectomy. Methods: Patients with lymph node metastases diagnosed during radical prostatectomy from 1988-2003 were reviewed. Patients with preoperative CT or MRI images were included in the study. Radiology reports were reviewed to determine if patients had clinically suspicious lymphadenopathy (cN+). For all analyses, patients with cN+ were compared to those with clinically negative nodes (cN−). Results: Preoperative imaging was available in 202 men with lymph node metastasis at the time of prostatectomy. Of these 17% (34/202) were cN+. None had pre-operative lymph node biopsy and none had abandoned prostatectomy. At a median follow-up of 11.1 years, PSA recurrence occurred in 50% (17/34) and 49% (82/186), local recurrence in 18% (6/34) and 13% (22/186) and systemic progression in 32% (11/34) and 24% (40/186) of patients with cN+ and cN-, respectively. On multivariate analysis, cN+ was not associated with increased risk of death (HR 1.66, p=0.1). Conclusions: cN+ patients undergoing surgical therapy for prostate cancer may experience similar outcomes to cN− patients. The presence of clinically suspicious lymph nodes on preoperative imaging should not be an absolute contraindication for surgical therapy. No significant financial relationships to disclose.

327 Background: To report long-term outcomes of patients (pts) treated with radiotherapy (RT) for stage II testicular seminoma. Methods: Between 1974 and 2007, 52 pts received RT for clinical stage II testicular seminoma after radical inguinal orchiectomy; 3 pts were excluded due to no clinical follow-up. CT staging was used for 46 pts (94%). Estimates of overall (OS), relapse-free (RFS), and cause-specific (CSS) survival were determined using the Kaplan-Meier technique. Major cardiac event (MCE) was defined as myocardial infarction, coronary artery bypass grafting or stenting, or valve replacement. Second malignancy (SM) was defined as biopsy-confirmed malignancy occurring in the RT field. Results: The median pt age was 35 years. AJCC stage was IIA (n=23), IIB (n=7), IIC (n=15), and unknown (n=4). Three pts were treated for paraortic recurrence during surveillance for stage I seminoma. Four pts with IIB (n=1) or IIC (n=3) disease were treated with chemotherapy in addition to RT. The median total RT dose was 30.4 Gy. Prophylactic mediastinal/supraclavicular (MSCV) RT was given to 24 pts (49%). The median follow-up was 18 years (range 0.4-37). Estimates of OS, RFS, and CSS at 10 and 20 years were 94% and 81%, 79% and 70%, and 96% and 96%, respectively. OS, RFS, and CSS were not significantly different between stage groups. Recurrence occurred in 9 pts (18%); sites were MSCV (n=6), para-aortic (n=1), lung (n=1), and peritoneal cavity (n=1). Seven pts were successfully salvaged, while 2 pts died of seminoma. No patient with stage IIA/B that received prophylactic MSCV RT (n=11) experienced MSCV relapse. Among patients that did not receive prophylactic MSCV RT, 2 of 13 (15%) with stage IIA and 3 of 6 (50%) with stage IIB experienced MSCV relapse. MCE occurred in 10 pts (20%) at a median of 18 years (range 7-30) after RT. SM occurred in 5 pts (10%) at a median of 27 years (range 20-34) after RT. Conclusions: Infradiaphragmatic RT alone was associated with a significant risk of MSCV failure, particularly in patients with stage IIB disease, suggesting that chemotherapy may be the optimal treatment in this patient cohort. Most MCE and SM events occurred more than 20 years after RT, highlighting the importance of vigilant long-term follow-up.

265 Background: UC response to CT is not durable. Angiogenesis may play a role in the progression of UC. We evaluated whether maintenance sunitinib delays progression after response to CT. Methods: Pts with ECOG PS 0-2, adequate organ function, stable disease, partial or complete response (SD, PR, CR) after 4-6 cycles of CT for advanced UC were randomized to oral sunitinib 50 mg/day, 28 days on, 14 days off (6-week cycle) or placebo. Disease was assessed every 12 wks. At progression, placebo pts were offered open label sunitinib. Primary endpoint: progression rate at 6 months (ms); secondary endpoints: safety, objective response rate, survival, VEGF/sVEGFR2 serum level changes. Using a randomized selection design 42 pts/arm has 90% probability of selecting sunitinib if true reduction in 6-ms progression rate is 15% (from 50% to 35%). Results: Study was closed early due to slow accrual. 54 pts with median age 69 years, median ECOG PS 1, 70% with bladder primary, 26 with SD, 23 with PR, 5 with CR to CT were randomized to sunitinib (26) or placebo (28). The median number of cycles was 2/arm (sunitinib 0-15, placebo 0-13). The 6-ms progression rate was 81% (95%CI 61-93%), median time-to-progression (TTP) 5 ms (0.3-22.2, 95%CI 2.4-6.3) for sunitinib and 75% (95%CI 55-89%), 2.7 ms (0.8-19.6, 95%CI 2.5-7.4) for placebo. Response rate in pts with SD at enrollment was 9% for sunitinib and 7% for placebo. Most common G3/4 AEs on sunitinib were diarrhea (15.4%/0%), fatigue (15.4%/3.8%), thrombocytopenia (15.4%/7.7%), hypertension (11.5%/0%). 16 placebo pts received sunitinib with best response 1 PR (6.25%), 6 SD (37.5%), 5 PD (31.25%); 4 not response evaluable. Median TTP was 3.4 ms (0.1-22, 95%CI 1.6-5.5). 11 pts had G3/4 AEs, 5 pts discontinued sunitinib due to AEs (4 related, 1 unrelated). Placebo pts had no change in VEGF/sVEGFR2 over time. Sunitinib pts had no change in VEGF but sVEGFR2 significantly decreased after 1 cycle (p<0.0001) and at progression (p=0.0002). VEGF/sVEGFR2 did not correlate with TTP. Conclusions: Maintenance sunitinib was feasible but did not improve 6-ms progression rate; open label sunitinib had limited activity. sVEGFR-2 decreased on sunitinib.

175 Background: The efficient delivery of adjuvant and salvage therapy after radical prostatectomy in patients with prostate cancer is hampered by a lack of biomarkers to assess the risk of clinically significant recurrence and progression. Methods: Mayo Clinic Radical Prostatectomy Registry (RP) patient specimens were selected from a case-control cohort with 14 years median follow-up for training and initial validation of an expression biomarker genomic classifier (GC). An independent, blinded case-cohort study of high-risk RP subjects was used to validate GC, comparing the performance of GC to a multivariate logistic regression clinical model (CM) and GC combined with clinical variables (genomic-clinical classifier, GCC) for predicting clinical recurrence (defined as positive bone or CT scan within 5 years after biochemical recurrence). The concordance index (c-index) and Cox model were used to evaluate discrimination and estimate the risk of clinical recurrence. Results: In the training subset (n=359), both GC and GCC had a c-index of 0.90 whereas CM had a c-index of 0.76. In the internal validation set (n=186), GC and GCC had a c-index of 0.76 and 0.75, while CM had a c-index of 0.69. In an independent high-risk study (n=219), GC and GCC had a c-index of 0.77 and 0.76, while CM had a c-index of 0.68. In subset analysis of Gleason score 7 patients within the high-risk group, GC and GCC showed improved discrimination with c-index of 0.78 and 0.76, respectively compared to 0.70 for CM. In the high-risk group, the risk of recurrence by GC model score quartiles at 5 years after RP was estimated at 1%, 5%, 5% and 18%. Conclusions: The GC model shows improved performance over CM in the prediction of clinical recurrence in a high-risk cohort and in subset analysis of Gleason score 7 patients. The addition of clinical variables to the GC model did not significantly contribute to classifier performance in patients with high-risk features. We are further testing the performance of the GC and GCC models and their usefulness in guiding decision-making (e.g., for the adjuvant therapy setting) in additional studies of prostate cancer clinical risk groups.

137 Background: LUTS are one of the most common reasons patients visit urologists. These symptoms have not been typically associated with the development of prostate cancer (CaP). However, we hypothesized that visiting a physician for LUTS may modify the diagnostic intensity for CaP compared to population controls. Methods: We examined data from a longitudinal, population-based cohort of 2,447 men between 40 and 79 years old who were followed prospectively from 1990 to 2010. Participants completed the American Urological Association Symptom Index (AUASI) every two years. Self-reported moderate/severe LUTS were defined as an AUASI score >7 (n=1627). Data including the treatment for LUTS (n=874), prostate biopsy (PBx), family history of CaP and diagnosis of CaP were obtained through self-report and review of medical records. Associations between self-reported LUTS, treatment for LUTS, and risk of PBx or CaP were estimated using multivariate Cox proportional hazard models. Results: An interaction was noted between age and LUTS and PBx and CaP diagnosis. In younger men, the diagnosis and treatment of LUTS was associated with increased risk of PBx (HR 2.39: 95% CI 1.83, 3.13) and CaP (HR 3.47: 95% CI 2.38, 5.07). Conversely in older men, treatment for LUTS was associated with a decreased risk of PBx and CaP (Table). Self reported LUTS was not significantly associated with CaP diagnosis in younger men and was protective in older men (Table). Conclusions: There is a differential effect of LUTS on prostate cancer testing and diagnosis when stratified by age. The reason for this difference is unclear, but appears to be due largely to diagnostic intensity rather than a true biologic association between LUTS and CaP. [Table: see text]

104 Background: Currently there are no serum predictive markers of response to AA. We used a proteomic based analytic approach to identify candidates. Methods: Serum from three non-localized prostate cancer cohorts was analyzed. The first included15 paired untreated hormone-sensitive “pre-AA” and 3-month “post-AA” specimens; the second included 10 “early AA failure” (median time to AA failure:11 months) and the third included 10 “late AA failure” specimens (median time to AA failure: 95 months). Proteomic analysis was performed with isobaric mass tags for relative and absolute quanititation (iTRAQ) analyzed by reverse-phase liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). Differentially expressed candidate proteins were identified by comparisons of (i) paired pre/post-AA proteomes and (ii) post-AA proteome with the combined AA failure cohorts at a False Discovery Rate of 0.2. ELISA assays were used to verify candidate markers in a second stored aliquot of first cohort specimens. This cohort was followed for AA failure. Association of post-AA ELISA levels of candidate markers with time to AA failure was performed using Cox proportional hazards regression, summarized as relative risk (RR) for AA failure. Results: Median PSA in pre/post-AA first cohort were 3.15 ng/ml and 0.29 ng/ml. Median PSA in the second and third cohorts were 27.3 and 4.3 ng/ml. Between post-AA and AA failure cohorts, 149 proteins were differentially expressed. Between early and late AA failure 98 proteins were differentially expressed; 47 proteins were common in both comparisons. ELISA assays verified expression levels of 2/47 proteins in the first cohort; zinc alpha-2 macroglobulin (ZAG), and Neuropilin-2 (NPL2). Median change in ZAG decreased by 2073.5 ng/ml (post versus pre-AA) while median change in NPL2 levels increased by 2.9 ng/ml. After a median follow-up of 43 months from the post-AA time-point, 4/15 first cohort subjects had failed AA. The RR of AA failure for ZAG levels below the median change was 3.8 (95% CI: 0.4-37) and 3.0 (95% CI: 0.3-29) for NPL2. Conclusions: A global proteomic analysis identified ZAG and NPL2 as candidate serum predictive markers of AA response which needs further validation.

LBA385 Background: Regorafenib (BAY 73-4506) is an oral multikinase inhibitor of a broad range of angiogenic, oncogenic, and stromal kinases. The phase III CORRECT trial was conducted to evaluate efficacy and safety of regorafenib in pts with mCRC who had progressed after all approved standard therapies. Methods: Enrollment criteria included documented mCRC and progression during or ≤3 months after last standard therapy. Pts were randomized 2:1 to receive regorafenib (160 mg od po, 3 weeks on/1 week off) plus BSC, or placebo (PL) plus BSC. Pts continued on treatment until progression, death, or unacceptable toxicity. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), overall response rate (ORR), disease control rate (DCR), safety, and quality of life. Results: From May 2010 to March 2011, 760 pts were randomized (regorafenib: 505; PL: 255). Baseline characteristics were balanced between two arms. Preliminary results are available from a pre-planned formal interim analysis. The estimated hazard ratio (HR) for OS was 0.773 (95% CI: 0.635, 0.941; 1-sided p=0.0051). Median OS was 6.4 mos (95% CI: 5.9, 7.3) for regorafenib and 5.0 mos (95% CI: 4.4, 5.8) for PL. The estimated HR for PFS was 0.493 (95% CI: 0.418, 0.581; 1-sided p < 0.000001). Median PFS was 1.9 mos (95% CI: 1.88, 2.17) for regorafenib and 1.7 mos (95% CI: 1.68, 1.74) for PL. ORR was 1.6% for regorafenib and 0.4% for PL. DCR was 44% for regorafenib and 15% for PL (p < 0.000001). Since the prespecified OS efficacy boundary was crossed (nominal α: 0.0093), the Data Monitoring Committee recommended to unblind the study and pts on PL were allowed to cross over to regorafenib. The most frequent grade 3+ AEs in the regorafenib arm were hand-foot skin reaction (17%), fatigue (15%), diarrhea (8%), hyperbilirubinemia (8%), and hypertension (7%). Updated results will be presented. Conclusions: Statistically significant benefit in OS and PFS was observed for regorafenib over PL in pts with mCRC who have failed all approved standard therapies. No new or unexpected safety signal was found.

535 Background: Prior ARIES analyses showed that BV-treated mCRC patients (pts) receiving chemotherapy (CT)/biologics + BV within 2 months (mo) after 1st progressive disease (PD) had longer post-progression survival (PPS) than pts receiving only CT/biologics. The present analysis evaluated whether this effect of BV was consistent when used with common 2L CT regimens— irinotecan- (iri-) and oxaliplatin- (ox-) based—in mCRC pts exposed to 1L BV in ARIES. Methods: ARIES enrolled mCRC pts receiving 1L CT + BV. No tx regimens or assessments were protocol specified. This analysis evaluated 1L BV-treated mCRC pts who had PD, survived ≥2 mo after PD, and received 2L iri- or ox-based tx. PPS was estimated by Kaplan-Meier methods. Cox regression was used to estimate hazard ratios (HRs), while adjusting for covariates (eg, 1L time to progression). Results: Of 1550 1L pts in ARIES, 1074 had 1st PD and survived ≥2 mo after PD. Of these 1074, 390 and 114 received 2L iri- and ox-based tx, respectively, ± BV ( table ). Baseline characteristics were generally similar between groups. The incidence of targeted adverse events (TAEs) was as expected and similar between the BV and No BV groups over time. In pts receiving 2L iri- or ox-based CT tx, PPS in BV-treated pts was longer compared to those not on BV. Analyses may be limited by small pt numbers in some groups. Conclusions: Consistent with prior ARIES analyses, the continued use of BV after 1st PD was associated with prolonged PPS regardless of the 2L CT backbone used. [Table: see text]