Baseline Circulating Tumor Cell Count as a Prognostic Marker of PSA Response and Disease Progression in Metastatic Castrate-Sensitive Prostate Cancer (SWOG S1216).

PURPOSE: In metastatic castrate-sensitive prostate cancer (mCSPC), combined androgen axis inhibition is a standard of care. Noninvasive biomarkers that guide initial therapy decisions are needed. We hypothesized that CellSearch circulating tumor cell (CTC) count, an FDA-cleared assay in metastatic castrate-resistant prostate cancer (mCRPC), is a relevant biomarker in mCSPC. EXPERIMENTAL DESIGN: SWOG S1216 is a phase III prospective randomized trial of androgen deprivation therapy (ADT) combined with orteronel or bicalutamide for mCSPC. CellSearch CTC count was measured at registration (baseline). Prespecified CTC cut-off points of 0, 1-4, and ≥5 were correlated with baseline patient characteristics and, in a stratified subsample, were also correlated with two prespecified trial secondary endpoints: 7-month PSA ≤0.2 ng/mL versus 0.2-4.0 versus >4.0 (intermediate endpoint for overall survival); and progression-free survival (PFS) ≤ versus >2 years. RESULTS: A total of 523 patients submitted baseline samples, and CTCs were detected (median 3) in 33%. Adjusting for two trial stratification factors (disease burden and timing of ADT initiation), men with undetectable CTCs had nearly nine times the odds of attaining 7-month PSA ≤ 0.2 versus > 4.0 [OR 8.8, 95% confidence interval (CI), 2.7-28.6, P < 0.001, N = 264] and four times the odds of achieving > 2 years PFS (OR 4.0, 95% CI, 1.9-8.5, P < 0.001, N = 336) compared with men with baseline CTCs ≥5. CONCLUSIONS: Baseline CTC count in mCSPC is highly prognostic of 7-month PSA and 2-year PFS after adjusting for disease burden and discriminates men who are likely to experience poor survival outcomes.

A phase I study of intravenous fenretinide (4-HPR) for patients with malignant solid tumors.

BACKGROUND: Fenretinide is a synthetic retinoid that can induce cytotoxicity by several mechanisms. Achieving effective systemic exposure with oral formulations has been challenging. An intravenous lipid emulsion fenretinide formulation was developed to overcome this barrier. We conducted a study to establish the maximum tolerated dose (MTD), preliminary efficacy, and pharmacokinetics of intravenous lipid emulsion fenretinide in patients with advanced solid tumors. METHODS: Twenty-three patients with advanced solid tumors refractory to standard treatments received fenretinide as a continuous infusion for five consecutive days in 21-day cycles. Five different dose cohorts were evaluated between doses of 905 mg/m2 and 1414 mg/m2 per day using a 3 + 3 dose escalation design. A priming dose of 600 mg/m2 on day 1 was introduced in an attempt to address the asymptomatic serum triglyceride elevations related to the lipid emulsion. RESULTS: The treatment-related adverse events occurring in ≥ 20% of patients were anemia, hypertriglyceridemia, fatigue, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) increase, thrombocytopenia, bilirubin increase, and dry skin. Five evaluable patients had stable disease as best response, and no patients had objective responses. Plasma steady-state concentrations of the active metabolite were significantly higher than with previous capsule formulations. CONCLUSION: Fenretinide emulsion intravenous infusion had a manageable safety profile and achieved higher plasma steady-state concentrations of the active metabolite compared to previous capsule formulations. Single-agent activity was minimal but combinatorial approaches are under evaluation.

Phase 2 trial of monoamine oxidase inhibitor phenelzine in biochemical recurrent prostate cancer.

PURPOSE: Monoamine oxidase A (MAOA) influences prostate cancer growth and metastasis in pre-clinical models. We examined effects of phenelzine (a monoamine oxidase inhibitor) in patients with biochemical recurrent castrate-sensitive prostate cancer. MATERIALS AND METHODS: An open-label single arm clinical trial enrolled subjects with biochemical recurrent prostate cancer defined by PSA ≥ 0.4 ng/ml (post prostatectomy) or PSA ≥ 2 ng/ml above nadir (post-radiation therapy); no evidence of metastasis on imaging; and normal androgen levels. Subjects received phenelzine 30 mg orally twice daily. Mood symptoms were assessed with the hospital anxiety depression score (HADS) questionnaire. The primary endpoint was the proportion of patients who achieved a PSA decline of ≥50% from baseline. RESULTS: Characteristics of the 20 eligible patients enrolled included: mean ± SD age 66.9 ± 4.8 years and PSA 4.7 ± 5.8 ng/dl. Maximal PSA declines ≥30% and ≥50% were observed in 25% (n = 5/20) and 10% (n = 2/20) of subjects, respectively. At 12 weeks, 17 subjects remained on treatment with PSA declines ≥30% and ≥50% of 24% (n = 4/17) and 6% (n = 1/17), respectively. Common toxicities observed included dizziness (grade 1 = 45%, grade 2 = 35%), hypertension (grade ≥ 2 = 30%), and edema (grade 1 = 25%, grade 2 = 10%). There was one episode of grade 4 hypertension (cycle 4) and two episodes of grade 3 syncope (cycle 12 and cycle 14) requiring treatment discontinuation. HADS questionnaires demonstrated a significant decrease in anxiety with no change in depressive symptoms on treatment. CONCLUSIONS: Phenelzine demonstrated efficacy in patients with biochemical recurrent castrate-sensitive prostate cancer. Most treatment-related toxicities were mild, but rare significant and reversible cardiovascular toxicities were observed. Therapies directed at MAOA may represent a new avenue for treatment in patients with recurrent prostate cancer.

Influence of the facility caseload on the subsequent survival of men with localized prostate cancer undergoing radical prostatectomy.

BACKGROUND: Several studies have investigated the relationship between experience measured by caseload and oncological outcomes, economics, and access to care for prostate cancer care. Oncological outcomes have been limited to biochemical failure after radical prostatectomy. Questions remain regarding the more definitive measures of outcomes and their relationship with caseload. METHODS: The National Cancer Database was used to investigate the outcomes of radical prostatectomy in the United States. With overall survival (OS) as the primary outcome, the relationship between the facility annual caseload (FAC) for all prostate cancer encounters and the facility annual surgical caseload (FASC) for those requiring radical prostatectomy was examined with a Cox proportional hazards model. Four volume groups were defined by caseload: <50th percentile (volume group 1 [VG1]), 50th to 74th percentiles (volume group 2 [VG2]), 75th to 89th percentiles (volume group 3 [VG3]), and ≥90th percentile (volume group 4 [VG4]). By FAC/FASC, 11%/8%, 17%/18%, 25%/26%, and 47%/49% of patients were treated in VG1 through VG4, respectively. RESULTS: Between 2004 and 2014, 488,389 patients underwent radical prostatectomy. At a median follow-up of 60.75 months, the median OS was not reached. There was a significant OS benefit as the caseload increased. For FAC, the adjusted OS difference between VG1 and VG4 at 90th percentile survivorship reached 13.2 months (hazard ratio [HR], 1.30; 95% CI, 1.23-1.36; P < .0001). For FASC, this was 11.3 months (HR, 1.25; 95% CI, 1.192-1.321; P < .0001). CONCLUSIONS: There is a statistically significant OS advantage from performing radical prostatectomy at a facility with a high annual caseload. Caseload measured by all prostate cancer encounters is a better predictor of favorable outcomes than the number of surgeries performed at a facility. LAY SUMMARY: An in-depth analysis of 488,389 cases of radical prostatectomy performed in more than 1000 facilities over a 10-year period showed better survival when surgery was performed in facilities with more experience and greater caseload. A survival difference of up to 13 months was observed when comparing patients treated at less experienced versus more experienced centers.   Experience across all stages of prostate cancer was a stronger predictor of survival outcome than just the number of surgeries performed.

Randomized Phase II Trial of Abiraterone Alone or With Dasatinib in Men With Metastatic Castration-resistant Prostate Cancer (mCRPC).

BACKGROUND: Signaling via the Src pathway is thought to be a mediator of resistance to androgen targeted therapy in prostate cancer. We studied whether adding the Src inhibitor dasatinib to abiraterone would delay progression. PATIENTS AND METHODS: Eligible patients had metastatic castration-resistant prostate cancer (mCRPC), without prior chemotherapy. Abiraterone was prescribed at 1000 mg daily with prednisone 5 mg twice daily in both arms, and dasatinib 100 mg daily was added for Arm B. The primary endpoint was progression-free survival (PFS). The interim analysis was planned after 48 subjects, but the study was terminated early. PFS was evaluated using a 1-sided log rank test. The Fisher exact test was used for other categorical data analyses. Circulating tumor cells (CTCs) were identified with the Epic platform. RESULTS: With 26 men randomized and a median follow up of 41.8 months, the median PFS was 15.7 months (95% confidence interval, 8.2-49.0+ months) for Arm B and 9.0 months (95% confidence interval, 4.4-30.7 months) for Arm A (P = .15). Response Evaluation Criteria in Solid Tumors responses were seen in 5 (36%) of 14 patients, including 2 complete responses (CRs) on Arm B, and 2 (17%) of 12 responses without CR on Arm A (P = .39). Grade ≥ 3 toxicities more common in Arm B included hypertension, pleural effusion/dyspnea, and gastrointestinal effects. CTCs were detected at baseline in 10 of 19 evaluable patients (median, 2.7/mL blood [range 0.41-59.7]). At week 4, CTCs increased in 1 (10%) of 10 patients on Arm A and 4 (44%) of 9 patients on Arm B. CONCLUSION: Dasatinib did not significantly prolong PFS in combination with abiraterone, although power was limited owing to the incomplete study cohort. Treatment with the combination was associated with robust objective responses, including Response Evaluation Criteria in Solid Tumors CRs.

Frequencies and expression levels of programmed death ligand 1 (PD-L1) in circulating tumor RNA (ctRNA) in various cancer types.

BACKGROUND: Precision medicine and prediction of therapeutic response requires monitoring potential biomarkers before and after treatment. Liquid biopsies provide noninvasive prognostic markers such as circulating tumor DNA and RNA. Circulating tumor RNA (ctRNA) in blood is also used to identify mutations in genes of interest, but additionally, provides information about relative expression levels of important genes. In this study, we analyzed PD-L1 expression in ctRNA isolated from various cancer types. Tumors inhibit antitumor response by modulating the immune checkpoint proteins programmed death ligand 1 (PD-L1) and its cognate receptor PD1. The expression of these genes has been implicated in evasion of immune response and resistance to targeted therapies. METHODS: Blood samples were collected from gastric (GC), colorectal (CRC), lung (NSCLC), breast (BC), prostate cancer (PC) patients, and a healthy control group. ctRNA was purified from fractionated plasma, and following reverse transcription, levels of PD-L1 expression were analyzed using qPCR. RESULTS: PD-L1 expression was detected in the plasma ctRNA of all cancer types at varying frequencies but no PD-L1 mRNA was detected in cancer-free individuals. The frequencies of PD-L1 expression were significantly different among the various cancer types but the median relative PD-L1 expression values were not significantly different. In 12 cases where plasma and tumor tissue were available from the same patients, there was a high degree of concordance between expression of PD-L1 protein in tumor tissues and PD-L1 gene expression in plasma, and both methods were equally predictive of response to nivolumab. CONCLUSIONS: PD-L1 mRNA can be detected and quantitated in ctRNA of cancer patients. These results pave the way for further studies aimed at determining whether monitoring the levels of PD-L1 mRNA in blood can identify patients who are most likely to benefit from the conventional treatment.

Novel Gene Expression Signature Predictive of Clinical Recurrence After Radical Prostatectomy in Early Stage Prostate Cancer Patients.

BACKGROUND: Current clinical tools have limited accuracy in differentiating patients with localized prostate cancer who are at risk of recurrence from patients with indolent disease. We aimed to identify a gene expression signature that jointly with clinical variables could improve upon the prediction of clinical recurrence after RP for patients with stage T2 PCa. METHODS: The study population includes consented patients who underwent a radical retropubic prostatectomy (RP) and bilateral pelvic lymph node dissection at the University of Southern California in the PSA-era (1988-2008). We used a nested case-control study of 187 organ-confined patients (pT2N0M0): 154 with no recurrence ("controls") and 33 with clinical recurrence ("cases"). RNA was obtained from laser capture microdissected malignant glands representative of the overall Gleason score of each patient. Whole genome gene expression profiles (29,000 transcripts) were obtained using the Whole Genome DASL HT platform (Illumina, Inc). A gene expression signature of PCa clinical recurrence was identified using stability selection with elastic net regularized logistic regression. Three existing datasets generated with the Affymetrix Human Exon 1.0ST array were used for validation: Mayo Clinic (MC, n = 545), Memorial Sloan Kettering Cancer Center (SKCC, n = 150), and Erasmus Medical Center (EMC, n = 48). The areas under the ROC curve (AUCs) were obtained using repeated fivefold cross-validation. RESULTS: A 28-gene expression signature was identified that jointly with key clinical variables (age, Gleason score, pre-operative PSA level, and operation year) was predictive of clinical recurrence (AUC of clinical variables only was 0.67, AUC of clinical variables, and 28-gene signature was 0.99). The AUC of this gene signature fitted in each of the external datasets jointly with clinical variables was 0.75 (0.72-0.77) (MC), 0.90 (0.86-0.94) (MSKCC), and 0.82 (0.74-0.91) (EMC), whereas the AUC for clinical variables only in each dataset was 0.72 (0.70-0.74), 0.86 (0.82-0.91), and 0.76 (0.67-0.85), respectively. CONCLUSIONS: We report a novel gene-expression based classifier identified using agnostic approaches from whole genome expression profiles that can improve upon the accuracy of clinical indicators to stratify early stage localized patients at risk of clinical recurrence after RP. Prostate 76:1239-1256, 2016. © 2016 Wiley Periodicals, Inc.

Predictors of time to biochemical recurrence in a radical prostatectomy cohort within the PSA-era.

INTRODUCTION: We sought to determine predictors for early and late biochemical recurrence following radical prostatectomy among localized prostate cancer patients. METHODS: The study included localized prostate cancer patients treated with radical prostatectomy (RP) at the University of Southern California from 1988 to 2008. Competing risks regression models were used to determine risk factors associated with earlier or late biochemical recurrence, defined using the median time to biochemical recurrence in this population (2.9 years after radical prostatectomy). RESULTS: The cohort for this study included 2262 localized prostate cancer (pT2-3N0M0) patients who did not receive neoadjuvant or adjuvant therapies. Of these patients, 188 experienced biochemical recurrence and a subset continued to clinical recurrence, either within (n=19, 10%) or following (n=13, 7%) 2.9 years after RP. Multivariable stepwise competing risks analysis showed Gleason score ≥7, positive surgical margin status, and ≥pT3a stage to be associated with biochemical recurrence within 2.9 years following surgery. Predictors of biochemical recurrence after 2.9 years were Gleason score 7 (4+3), preoperative prostate-specific antigen (PSA) level, and ≥pT3a stage. CONCLUSIONS: Higher stage was associated with biochemical recurrence at any time following radical prostatectomy. Particular attention may need to be made to patients with stage ≥pT3a, higher preoperative PSA, and Gleason 7 prostate cancer with primary high-grade patterns when considering longer followup after RP.

Phase I, dose-escalation study of the targeted cytotoxic LHRH analog AEZS-108 in patients with castration- and taxane-resistant prostate cancer.

PURPOSE: AEZS-108, formerly AN-152, is a cytotoxic hybrid molecule consisting of a luteinizing hormone-releasing hormone (LHRH) agonist moiety covalently coupled to doxorubicin, allowing it to deliver doxorubicin selectively to cells expressing LHRH receptors. LHRH receptors are expressed on the cell membrane of many tumors, including prostate cancer. This phase I study determined the maximum tolerated dose (MTD) of AEZS-108 in men with taxane- and castration-resistant prostate cancer (CRPC) while providing additional information on the safety profile and efficacy of this agent. EXPERIMENTAL DESIGN: AEZS-108 was administered as an intravenous infusion every 21 days until progression or unacceptable toxicity in cohorts of 3 or 6 patients until the MTD was reached. Blood was collected for capture of circulating tumor cells (CTC) to visualize internalization of AEZS-108, an autofluorescent molecule. RESULTS: The MTD of AEZS-108 in this cohort was 210 mg/m(2), which was lower than that seen in a phase I study conducted in women with endometrial or ovarian cancers. The dose-limiting toxicity was persistent neutropenia. Three patients had a PSA response with an additional 10 patients maintaining PSA stable disease. Of the 10 patients evaluable by RECIST criteria, 9 achieved stable disease. AEZS-108 internalization in CTCs was routinely visualized using its autofluorescence. CONCLUSION: These findings show that AEZS-108 has an acceptable safety profile and a signal of efficacy, lowering PSA in heavily pretreated patients with prostate cancer, and that internalization of AEZS-108 in prostate cancer CTCs may be a viable pharmacodynamic marker. A phase II study in men with prostate cancer is ongoing.

Epidermal growth factor receptor-targeted therapy in squamous cell carcinoma of the penis: a report of 3 cases.

OBJECTIVE: To describe 3 cases of advanced refractory penile cancer treated with targeted therapy against the epidermal growth factor receptor (EGFR). MATERIALS AND METHODS: We identified 3 patients with advanced penile cancer who had disease progression after platinum chemotherapy refractory and who subsequently received EGFR-targeted therapy. Their tumor tissue was evaluated for expression of EGFR by immunohistochemistry and messenger ribonucleic acid quantitation and was also tested for the presence of human papillomavirus deoxyribonucleic acid by line hybridization. K-ras mutation was evaluated by polymerase chain reaction for 6 mutations in codon 12 and 1 mutation in codon 13. RESULTS: One patient responded to cetuximab and remains disease-free 42 months after presentation. One patient responded to panitumumab, then suffered relapse. One other progressed through EGFR-targeted therapy. EGFR expression by immunohistochemistry was 1-2+ in all cases, and messenger ribonucleic acid expression ranged from 4.08 to 7.33. No K-ras mutations or human papillomavirus deoxyribonucleic acid was detected. CONCLUSION: We report 3 cases in which EGFR-targeted therapy was used to treat platinum-refractory penile cancer patients. Because 2 of the 3 had clinical benefit, future prospective trials of EGFR-targeted therapy in penile cancer are warranted.

Efficacy of oxaliplatin plus pemetrexed in chemotherapy pretreated metastatic castration-resistant prostate cancer.

BACKGROUND: Although new androgen-targeted therapies offer prolonged survival in metastatic castration-resistant prostate cancer (CRPC), most men still face progressive disease and require additional therapy. Oxaliplatin and pemetrexed have each shown modest activity in the treatment of CRPC. Given their favorable nonoverlapping toxicity profiles, we studied them in combination. PATIENTS AND METHODS: Men with CRPC whose disease had progressed on 1 or 2 previous chemotherapy regimens, including a taxane, were eligible. All participants received oxaliplatin 120 mg/m(2) and pemetrexed 500 mg/m(2) intravenously every 21 days. The primary end point was response rate; objective responses were determined using Response Evaluation Criteria in Solid Tumors (RECIST), version 1.0, criteria and the Prostate Cancer Working Group (1999) criteria. Secondary end points included progression-free survival and OS. RESULTS: Forty-seven men received a median of 6 cycles (range, 1-21). The overall response rate was 30% (95% confidence interval [CI], 18%-45%), including 10 men with RECIST responses of the 40 who had measurable disease (25%). Overall, 64% had a prostate-specific antigen (PSA) decline and 74% of men had clinical disease control (partial response or stable disease as their best response). Median progression-free survival was 5.8 months (95% CI, 3.8-7.6), with a median OS of 11.9 months. Six of 15 evaluable patients (40%) experienced a pain response. Nineteen patients (40%) experienced a grade 3 or 4 hematologic toxicity, and 16 (34%) experienced a grade 3 nonhematologic toxicity. One patient died while participating in the study. CONCLUSION: Combination oxaliplatin and pemetrexed (PemOx) is an effective and tolerable second- or third-line treatment for men with CRPC.

Baseline 18F-FDG PET/CT parameters as imaging biomarkers of overall survival in castrate-resistant metastatic prostate cancer.

UNLABELLED: The aim of this prospective investigation was to assess the association of parameters derived from baseline (18)F-FDG PET/CT with overall survival (OS) in men with castrate-resistant metastatic prostate cancer. METHODS: Eighty-seven men with castrate-resistant metastatic prostate cancer underwent (18)F-FDG PET/CT and were followed prospectively for OS. Median follow-up in patients who were alive was 22.2 mo (range, 1.6-62.5 mo). OS was defined as the time between the PET/CT imaging or the start of chemotherapy, whichever was later, and death, with patients who were alive censored at the last follow-up date. PET parameters included maximum standardized uptake value (SUV(max)) of the most active lesion, sum of SUV(max), and average SUV(max) of all metabolically active lesions, after subtraction of patient-specific background-liver average SUV. Comparison of OS was based on univariate and multivariable Cox regression analyses of continuous PET parameters adjusted for standard clinical parameters (age, serum prostate-specific antigen level, alkaline phosphatase, use of pain medication, prior chemotherapy, and Gleason score at initial diagnosis). Survival curves based on Kaplan-Meier estimates are presented. RESULTS: Among the 87 patients, 61 were dead at the time of last follow-up. Median OS was 16.5 mo (95% confidence interval [CI], 12.1-23.4 mo), and the OS probability at 24 mo was 39% ± 6%. For the univariate analysis, the hazard ratios associated with each unit increase were 1.01 (95% CI, 1.006-1.02) for sum of SUV(max) (P = 0.002), 1.11 (95% CI, 1.03-1.18) for maximum SUV(max) (P = 0.010), and 1.13 (95% CI, 0.99-1.30) for average SUV(max) (P = 0.095). For the multivariable analysis adjusting for relevant clinical parameters, the continuous parameter sum of SUV(max) remained significant (P = 0.053), with a hazard ratio of 1.01 (95% CI, 1.001-1.02). When sum of SUV(max) was grouped into quartile ranges, there was poorer survival probability for the patients in the fourth-quartile range than for those in the first-quartile range, with a univariate hazard ratio of 3.8 (95% CI, 1.8-7.9). CONCLUSION: Sum of SUV(max) derived from (18)F-FDG PET/CT contributes independent prognostic information on OS in men with castrate-resistant metastatic prostate cancer, and this information may be useful in assessing the comparative effectiveness of various conventional and emerging treatment strategies.

Prospective evaluation of 18F-NaF and 18F-FDG PET/CT in detection of occult metastatic disease in biochemical recurrence of prostate cancer.

PURPOSE: This study aimed to perform a prospective evaluation of 18F-NaF and 18F-FDG PET/CT in the detection of occult metastatic disease in men with prostate cancer and biochemical relapse. METHODS: Thirty-seven men with prostate-specific antigen (PSA) relapse (median, 3.2 ng/mL; range, 0.5-40.2 ng/mL) after definitive therapy for localized prostate cancer [26 radical prostatectomy (RP), 11 external beam radiation therapy] and negative conventional imaging underwent 18F-FDG and 18F-NaF PET/CT on 2 separate days within the same week. Studies were interpreted by 2 experienced radiologists in consensus for abnormal uptake suspicious for metastatic disease. The reference standard was a combination of imaging and clinical follow-up. Rank of PSA values for positive and negative PET/CT was compared using analysis of variance adjusting for primary therapy. Association between PSA and scan positivity in patients with RP was evaluated using Wilcoxon rank sum test. RESULTS: Result of the 18F-FDG PET/CT scan was positive for nodal disease in 2 patients. True-positive detection rate for occult osseous metastases by 18F-NaF PET/CT was 16.2%. Median PSA levels for positive versus negative PET/CT scans were 4.4 and 2.9 ng/mL, respectively, with the difference marginally significant in prostatectomized men (P=0.072). Percentages of patients with either 18F-NaF- or 18F-FDG-positive PET/CT in RP and external beam radiation therapy were 10% (n=10) and undefined (n=0) for a PSA of 2 ng/mL or less, 29% (n=7) and 50% (n=2) for PSA greater than 2 ng/mL but 4 ng/mL or less, 60% (n=5) and 40% (n=5) for PSA greater than 4 ng/mL but 10 ng/mL or less, and 25% (n=4) and 25% (n=4) for PSA greater than 10 ng/mL, respectively. CONCLUSIONS: In biochemical relapse of prostate cancer, 18 F-NaF PET/CT is useful in the detection of occult osseous metastases, whereas the yield of 18F-FDG PET/CT is relatively limited. 18F-NaF PET/CT positivity tends to associate with increasing PSA level in prostatectomized men and may occur in lower PSA ranges than conventionally recognized.

Immune response to sipuleucel-T in prostate cancer.

Historically, chemotherapy has remained the most commonly utilized therapy in patients with metastatic cancers. In prostate cancer, chemotherapy has been reserved for patients whose metastatic disease becomes resistant to first line castration or androgen deprivation. While chemotherapy palliates, decreases serum prostate specific antigen and improves survival, it is associated with significant side effects and is only suitable for approximately 60% of patients with castrate-resistant prostate cancer. On that basis, exploration of other therapeutic options such as active secondary hormone therapy, bone targeted treatments and immunotherapy are important. Until recently, immunotherapy has had no role in the treatment of solid malignancies aside from renal cancer and melanoma. The FDA-approved autologous cellular immunotherapy sipuleucel-T has demonstrated efficacy in improving overall survival in patients with metastatic castrate-resistant prostate cancer in randomized clinical trials. The proposed mechanism of action is reliant on activating the patients' own antigen presenting cells (APCs) to prostatic acid phosphatase (PAP) fused with granulocyte-macrophage colony stimulating factor (GM-CSF) and subsequent triggered T-cell response to PAP on the surface of prostate cancer cells in the patients body. Despite significant prolongation of survival in Phase III trials, the challenge to health care providers remains the dissociation between objective changes in serum PSA or on imaging studies after sipleucel-T and survival benefit. On that basis there is an unmet need for markers of outcome and a quest to identify immunologic or clinical surrogates to fill this role. This review focuses on the impact of sipuleucel-T on the immune system, the T and B cells, and their responses to relevant antigens and prostate cancer. Other therapeutic modalities such as chemotherapy, corticosteroids and GM-CSF and host factors can also affect immune response. The optimal timing for immunotherapy, patient selection and best sequencing with other prostate cancer therapies remain to be determined. A better understanding of immune response may help address these issues.

Vaccine therapy with sipuleucel-T (Provenge) for prostate cancer.

As the most common malignancy among North American males, prostate cancer causes more than 30,000 deaths each year. After local and hormonal treatments, a great number of patients ultimately progressed to castrate-resistant prostate cancer (CRPC), in which chemotherapy provides a small survival advantage, but with significant toxicities. In the past decade, prostate cancer has become a target for several immunotherapeutic approaches. Sipuleucel-T (Provenge®, or APC8015) is a novel cancer vaccine developed from autologous dendritic cells (DC) loaded with engineered fusion protein of prostatic acid phosphatase (PAP) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Phase I and Phase II trials show that the vaccine is safe and effective in creating immune responses toward the fusion-protein target antigen, PAP-GM-CSF also call PA2024. Recent Phase III studies also demonstrated sipuleucel-T's efficacy in prolonging median survival in patients with CRPC, despite little or no effect on clinical disease progression or surrogates such as serum PSA kinetics. Subsequently, the United States Food and Drug Administration approved sipuleucel-T for the treatment of asymptomatic or minimally symptomatic CRPC in April 2010. Filings are projected with international regulatory agencies in 2011. While the development of sipuleucel-T provides an option for patients with early CRPC, it also introduces physicians and researchers to new unanswered questions regarding its optimal clinical use and questions about mechanism of action and combination and sequencing with other agents.

The relationship between proangiogenic gene expression levels in prostate cancer and their prognostic value for clinical outcomes.

BACKGROUND: Androgens stimulate the expression of vascular endothelial growth factor (VEGF) through activation of hypoxia inducible factor (HIF). These genes play a major role in cancer angiogenesis. This study assesses the relationship among expression levels for the androgen receptor (AR), HIF1a, VEGF-A, and VEGF-C genes in human prostate cancer tissue and their impact on prostate cancer outcomes. It also examines the impact of pre-operative androgen deprivation therapy (ADT) on the expression of these genes. METHODS: Radical prostatectomy specimens were obtained from 138 patients with D1 prostate cancer from the University of Southern California prostatectomy database; 30% received pre-operative and 23% received post-operative ADT. Gene expression levels were determined by quantitative real-time PCR. Specimens were stratified into three groups for each gene based on expression levels, and groups were compared for clinical outcomes (PSA and clinical recurrence, overall survival). RESULTS: There was a significant correlation in expression levels amongst all genes. Patients treated with pre-operative ADT had significantly lower HIF1a expression, mean 2.64 (CI 2.34-2.94) than patients not treated, mean 3.25 (CI 2.97-3.53, P = 0.006), adjusting for age, PSA, Gleason score, and stage. Higher VEGF-A expression was significantly associated with better overall survival (HR 0.49, P = 0.015). The risk of developing clinical recurrence was significantly lower with higher VEGF-C expression (HR 0.4, P = 0.014). CONCLUSIONS: Significant correlation was noted among AR, HIF1a, VEGF-A, and VEGF-C. This study shows that ADT is associated with lower HIF1a gene expression in human prostate cancer tissue and documents prognostic value for VEGF-A and VEGF-C expression levels.

Clinical and correlative results of SWOG S0354: a phase II trial of CNTO328 (siltuximab), a monoclonal antibody against interleukin-6, in chemotherapy-pretreated patients with castration-resistant prostate cancer.

PURPOSE: Interleukin-6 (IL-6) facilitates cancer cell survival via pleotrophic effects. We conducted a multicenter phase II study of CNTO328 (siltuximab) as second-line therapy for men with castration-resistant prostate cancer. EXPERIMENTAL DESIGN: Eligible men had castration-resistant prostate cancer treated with one prior chemotherapy. Subjects were treated with 6 mg/kg CNTO328 i.v. every 2 weeks for 12 cycles. Response was assessed after every three cycles. Primary end point was prostate-specific antigen (PSA) response rate defined as a 50% reduction. Accrual was planned in two stages, with 20 eligible patients in the first stage and 40 overall. Plasma cytokines and growth factors were measured by Luminex. RESULTS: Fifty-three eligible subjects had all received prior taxane therapy. Two (3.8%; 95% CI, 0.5-13.0%) had PSA response. None of the 31 patients with measurable disease had a RECIST (Response Evaluation Criteria in Solid Tumors) response but 7 (23%) had stable disease. With median follow-up of 14.8 months, median progression-free survival was 1.6 months (95% CI, 1.6-1.7) and median overall survival was 11.6 months (95% CI, 7.5-19.0). Grade 3/4 toxicities included disseminated intravascular coagulation (1), central nervous system ischemia (1), elevated aspartate aminotransferase (1), gastritis/esophagitis (2), thrombocytopenia (2), pain (2), leukopenia (1), and neuropathy (2). Median baseline IL-6 levels were 12.5 pg/mL (interquartile range, 2.5-41.5). Patients with IL-6 >12.5 pg/mL had worse survival than those with levels <12.5 pg/mL (53% versus 94%; P = 0.02). After treatment, IL-6 levels were >250-fold higher. Thirty-two of 38 patients had a decline in C-reactive protein plasma levels at 6 weeks. CONCLUSIONS: CNTO328 resulted in a PSA response rate of 3.8% and a RECIST stable disease rate of 23%. Declining C-reactive protein levels during treatment may reflect biological activity. Despite evidence of CNTO-mediated IL-6 inhibition, elevated baseline IL-6 levels portended a poor prognosis.

Gene profiling and pathway analysis of neuroendocrine transdifferentiated prostate cancer cells.

BACKGROUND: Neuroendocrine (NE) cells are present in both normal prostate and prostate cancer. In addition, NE differentiation can be induced by various factors, such as IL-6, in vitro and in vivo. However, the mechanism of this differentiation and the role of NE cells in prostate cancer are not well understood. In this study, we evaluated the gene expression and analyzed the pathways in prostate cancer cells exposed to various NE differentiation inducing factors in vitro. METHODS: Gene expression signatures between control LNCaP cells and each treatment induced NE cell line were compared using Affymetrix GeneChip with network and pathway analysis. RESULTS: All treatments were able to transdifferentiate LNCaP cells into NE phenotype as shown by morphology changes and NE marker measurements. Of the 54,675 oligonucleotide-based probe sets in microarray, 44,975 were mapped into the Ingenuity Pathway Analysis database and were filtered according to the t-test P value. At P < 0.002, the number of genes that were differentially expressed included 302 of the IL-6 treated cells, 201 of genistein, 233 of epinephrine, and 191 of the charcoal stripped serum ones. A pooled data approach also showed 346 differentially expressed genes at the same P value. Gene ontology analysis showed that cancer-related function had the highest significance. CONCLUSIONS: Despite some overlap, each NE transdifferentiation inducing treatment was associated with a changed expression of a unique set of genes, and such gene profiling may help to elucidate the molecular mechanisms involved in NE transdifferentiation of prostate cancer cells.

A phase II study of high-dose calcitriol combined with mitoxantrone and prednisone for androgen-independent prostate cancer.

OBJECTIVE: To evaluate the preliminary efficacy, safety, and impact on quality of life (QoL) of high-dose calcitriol (DN-101) combined with mitoxantrone and glucocorticoids in androgen-independent prostate cancer (AIPC). PATIENTS AND METHODS: Nineteen patients with metastatic AIPC and no previous chemotherapy received DN-101 180 microg orally on day 1 and mitoxantrone 12 mg/m(2) intravenously on day 2 every 21 days with continuous daily prednisone 10 mg orally for a maximum of 12 cycles. A confirmed decline in prostate-specific antigen (PSA) levels by half was the primary endpoint. QoL was evaluated using the European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire, and pain and analgesic use were evaluated. RESULTS: Five of 19 patients (26%; 95% confidence interval, CI, 9-51) achieved a >/=50% decline in PSA level. The median (95% CI) time to PSA progression was 16 (6-26) weeks. The overall median (95% CI) survival was 16 (6-26) months; 47 (21-73)% of patients achieved an analgesic response. Toxicity was similar to that expected with mitoxantrone and prednisone alone. The QoL analysis suggested a decrease in physical functioning and increase in fatigue, insomnia, and diarrhoea. CONCLUSIONS: DN-101 given every 3 weeks does not add significant activity to mitoxantrone and prednisone in AIPC, as measured by the PSA decline. The high rate of analgesic response is encouraging. The addition of DN-101 does not appear to increase the toxicity of mitoxantrone.

Both beta-actin and GAPDH are useful reference genes for normalization of quantitative RT-PCR in human FFPE tissue samples of prostate cancer.

BACKGROUND: Beta-actin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) have been frequently considered as constitutive house keeping genes for RT-PCR and used to normalize changes in specific gene expressions. However, these expressions have been shown to be affected by the sample type and experimental conditions. We investigated which housekeeping gene is useful to study gene expression of paraffin embedded human tissue samples of prostate cancer. METHODS: Fifteen pairs of cancer and corresponding normal tissue were obtained from patients with prostate cancer. We evaluated gene expression of beta-actin, GAPDH, androgen receptor (AR), and heat-shock 70-kd protein 5 (HSPA5) using laser captured microdissection and quantitative RT-PCR. AR and HSPA5 gene expression were normalized to each of these reference genes using the 2(-DeltaDeltaCt) method of relative quantification. The quantity 2(Ct(normal)-Ct(cancer)) divided by ratio of cDNA(cancer)/cDNA (normal) was used for comparing differences between cancer and normal tissue in GAPDH and beta-actin expression. RESULTS: Ct value of beta-actin was significantly correlated with that of GAPDH (r = 0.443, P = 0.014). AR and HSPA5 gene expression levels using beta-actin for normalization were significantly correlated with these gene expression levels using GAPDH (AR; r = 0.689, P = 0.004, HSPA5; r = 0.879, P < 0.001). Both reference genes were expressed more highly in cancer tissue than in normal tissue, with that of GAPDH being significantly different between cancer tissue and normal tissue (P = 0.029). CONCLUSIONS: The good correlation between gene expression values obtained when using beta-actin and GAPDH as reference genes suggests that either gene is a valid denominator for gene expression studies in prostate cancer.