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.

Baseline circulating tumor cell (CTC) count as a prognostic marker of PSA response and progression in metastatic castrate sensitive prostate cancer (mCSPC): Results from SWOG S1216, a phase III randomized trial of androgen deprivation plus orteronel (cyp17 inhibitor) or bicalutamide

5506

Background: In mCSPC, androgen deprivation therapy (ADT) combined with chemotherapy or androgen receptor signaling inhibition (ARSI) is the new standard of care. Biomarkers that predict clinical outcomes with these therapies are needed. We hypothesized that CellSearch CTC count, an FDA-cleared biomarker in metastatic castrate resistant PC (mCRPC), may be a valuable biomarker in mCSPC. Methods: In S1216, peripheral blood was drawn with informed consent at registration (baseline), and CTCs were enumerated on the FDA-cleared CellSearch platform (Menarini) per standard manufacturer protocol. CTC counts were analyzed centrally for associations with 2 pre-specified trial intermediate endpoints: 7-month PSA (7mPSA) ≤ 0.2 ng/ml vs. 0.2–4.0 vs. > 4.0, (intermediate endpoint for overall survival, OS); and progression-free survival (PFS) < vs. > 2 years. Because OS data have not matured, analysis was pooled and equal numbers of samples were analyzed from each treatment arm and outcome measure (7mPSA and PFS) as stipulated by the Data Safety Monitoring Committee. Results: From 2014 to 2017, 523 baseline samples were collected. In the 7mPSA analysis (n = 264), CTCs were detected in 38% of men, with a median of 4 CTCs in those with detectable CTCs. In the PFS analysis (n = 336), CTCs were detected in 37% of men, with a median of 3 CTCs in those with detectable CTCs. Adjusting for disease burden (minimal vs. extensive) and ADT status (already initiated or not) at the time of CTC measurement, men with undetectable CTCs were 6.1-fold more likely to attain 7mPSA ≤ 0.2 (OR 6.1, 95% CI 2.1-17.2, p < 0.001) and 3.7-fold more likely to achieve > 2 years PFS (OR 3.7, 95% CI 1.7-8.1, p < 0.001) compared to men with baseline CTCs ≥ 5. Other cutpoints previously validated in mCRPC studies (CTC < 5 vs. ≥5 and CTCs 0 vs. ≥1) also strongly discriminated 7mPSA and PFS with statistical significance in this mCSPC cohort. Conclusions: CTC count at the start of treatment for mCSPC was highly prognostic of 7-month PSA response (intermediate endpoint for OS) and of PFS at 2 years. To our knowledge, this is the first such strong evidence from a prospective phase 3 trial of this magnitude. Additional analyses are planned when the trial is fully reported. Baseline CTC count may serve as a valuable prognostic marker to discriminate men likely to respond favorably to hormonal therapies from those who may benefit from early alternate interventions.

Influence of caseload on survival of patients (pts) with localized prostate cancer (PC) after definitive radiation therapy (DRT)

357

Background: We recently reported a significant all-cause mortality risk reduction associated with higher annual caseload for radical prostatectomy (RP)- (PMID 31398279). Here we explore this relationship in DRT. Methods: National Cancer Database (NCDB) was used to investigate outcomes of DRT in the United States. Beam radiation (BR), radioactive implant (RI) and both (BRRI) were included in analysis. Using overall survival (OS) as primary outcome, the relationship between facility annual caseload (FAC) for all PC pts and facility annual caseload (FARC) for those requiring DRT were examined using Cox model. Four volume groups (VG) were defined as VG1: <50th, VG2: 50th-74th, VG3: 75th-89th and VG4: top 10 percentile of caseload. Results: Between 2004 and 2014, 355,247 pts underwent DRT. At a median follow up of 70.1 (95% CI: 1.0 - 143.1) months (mo), the median OS was 137.3 mo (136.9, 138.1). Using FAC/FARC, 19/14, 27/24, 24/26, and 30/37 % of pts were treated at VG 1 through 4, respectively. For FARC, median OS was 136.8 mo (134.9, 142.2+) for VG1 and 139.7 (137.7, 141.8+) mo for VG4, adjusted hazard ratio (aHR) 1.06 (1.03-1.09), p <0.001. For FAC, median OS was 135.4 (134.1, 138.7) mo for VG1 and not reached for VG4, aHR 1.13 (1.09, 1.16), p <0.001. In subgroups, FARC aHR for VG1 vs VG4 were 1.20 (1.16-1.25) for BR, 0.99 (0.93-1.05) for RI, and 1.15 (1.02-1.31) for BRRI. These numbers for FAC were 1.10 (1.06, 1.14), 1.12 (1.05, 1.19), and 1.24 (1.12, 1.39), respectively. Conclusions: There is a statistically significant OS advantage to DRT at a high annual caseload facility. This effect is more pronounced for BR and is influenced more noticeably by facility all PC caseload rather than DRT.[Table: see text]

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

94

Background: 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. 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 1 episode of grade 4 hypertension (cycle 4) and 2 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. Clinical trial information: NCT02217709.

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.

Association of next generation sequencing characteristics of MIBC specimens with clinical outcomes: The USC experience

397

Background: Muscle invasive bladder cancer (MIBC) is an aggressive disease. Several molecular subtypes have been identified. Commercial next generation sequencing (NGS) panels now provide significant genetic information on tumors. We conducted an exploratory analysis on MIBC tumor samples at our institution with commercial NGS data to evaluate if these assays provide novel prognostic information. Methods: NGS data (FoundationOne) from all locally advanced and metastatic bladder specimens were collected and combined with information on demographics, tumor characteristics (stage, grade, histology). Overall Survival (OS), post-cystectomy disease free survival (DFS), and Progression Free Survival (PFS) data were also compiled. Mutations in 353 genes were examined for alterations in TP53, Rb, FGF3-RAS-RAF and PI3K-mTOR-AKT pathways. Results: 48 samples were analyzed. Most samples were pure TCC (68.8%) followed by Squamous (16.8%) , Adenocarcinoma (6.3%), Small Cell (6.3%) and Plasmacytoid variants (2.1%). Most patients (91.5%) were locally advanced at diagnosis. Pathologic alterations were found in TP53 (54.2%) , Rb (60.4%), FGF3-RAS-RAF(89.6%) and PI3K-mTOR-AKT(70.8%) pathways. Squamous variants were more likely to have TP53 pathway alterations compared with others (100% vs 45% , p < 0.001) and predicted for poor overall survival. TP53 exons did not predict outcomes. In multivariable adjusted cox-regression models Rb alterations appeared to predict for improved post cystectomy DFS (p = 0.01). TP53 mutations predicted for worse PFS (p=0.01) while PI3K-mTOR-AKT pathway alterations were associated with poorer OS (p=0.02) after adjusting for all other predictors. Conclusions: In this limited single institution sample analyzed by commercial available NGS panels, some prognostic information was available. Analysis of a larger population could result in the validation of other predictive or prognostic markers.[Table: see text]

EphB4-EphrinB2 receptor-ligand pair as a novel target in prostate cancer (PC)

275

Background: Studies have shown that EphB4 (B4), a receptor kinase, is upregulated in PC. The ligand for B4, EphrinB2 (B2) has not been studied in PC thus far. In our PTEN null mouse PC model, B4 and B2 are both upregulated in PC, but not in normal prostate. Furthermore, Soluble B4-albumin (sB4) decoy receptor blocks B4-B2 bidirectional signaling, inhibits PI3K/AKT signaling and is currently in phase II clinical trials in multiple tumor types. We thus studied B2 expression in human PCs and normal tissues. Methods: B2 levels were studied in 180 clinically localized human PCs and normal prostates. Tissue staining was performed with specific monoclonal antibody, using LEICA platform. B2 expressions in tumor vessel, tumor cell and stromal cells were scored by a pathologist. In addition, a CRPC patient was treated with sB4 under an IND approved by the FDA and IRB. The patient’s prostate cancer was diagnosed in 2014, Gleason’s score 4+3, treated with radical prostatectomy (pT3bN0) with subsequent metastases bone/bone marrow and progression on sipuleucel T, enzalutamide, abiraterone, docetaxel, cabazitaxel, and carboplatin. Tumor and blood samples were obtained and analyzed after informed consent. Results: B2 was not expressed in any of the 40 normal prostate gland or normal vessels in bladder, pancreas, small intestine, liver, adrenal glands, skeletal muscle, and bone marrow tissues. B2 was expressed 50% of the human prostate cancer tissues, being positive in tumor cells and negative in vascular and stromal cells. Expression was correlated with Gleason score (p = 0.003). B2 was also upregulated in PC cell lines that are characterized for genomic, and epigenomic alterations to study mechanisms of B2 induction. Metastatic tumor tissue from the CRPC patient showed high elevation of B2. After a 4-week course of sB4, PSA level declined by 45% (from 2284 to 1257). PI3K and AR levels in tumor tissue declined compared to baseline. PI3K/AKT/pS6 and AR levels in tumor tissue ex-vivo studies were also reduced with sB4 exposure. Conclusions: B2 is expressed in half of PCs and our experiments suggest a significant role for the EphB4-EphrinB2 pair through regulation of PI3K and AR signaling. Given the central role of AR in PC, sB4 may offer a novel approach to targeting AR.

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.

Relationship between neutrophil lymphocyte ratio (NLR) and MDSC concentration in localized and metastatic castration resistant prostate cancer (mCRPC) patients

338

Background: Human Myeloid Derived Suppressor Cells (MDSCs) have gained recognition as a significant population of cells that arise in cancer patients to mediate immune tolerance. MDSCs have been validated as a prognostic factor in several tumor types. The Neutrophil-Lymphocyte Ratio (NLR) is an easily obtained marker of inflammation that has also been validated as a prognostic marker in tumors including prostate cancer. We measured and compared MDSC concentrations and NLR in a cohort of patients with prostate cancer and also examined thier relationship with PSA Progression, a validated marker of overall survival. Methods: Blood was collected from patients with localized prostate cancer (n = 14) and mCRPC (n = 44) at 0 and 6 months. The percent CD33+ HLA-DRlow HIF1a+, CD33+ HLADRlow C/EBPb+, CD11b+ HLA-DRlow HIF1a+, and CD11b+ HLA-DRlow C/EBPb+cells as a fraction of PBMC were determined and reported. NLRs were obtained within 4 weeks of MDSC measurements. Patients were followed for a period of 2 years; PSA-Progression (PSA-P) was defined as a PSA doubling time of < 3 months in association with an increase of at least > 5ng/mL from PSA nadir Results: Higher Gleason scores were statistically associated with a NLR of greater than 2 (r = 0.07, p = 0.02, 95% CI [0.01-0.14]). Increasing MDSC% did not correlate with increasing Gleason scores (r = 0.13, p = 0.31) or predict PSA-P at 6 months (p = 0.16). MDSC% in patients with mCRPC (4.25%, 95% CI[3.34-5.17]) were significantly higher than localized prostate cancer (1.7%, 95% CI[1.02-2.37]) . There was a highly statistically significant relationship between the percentage of MDSC in PBMC with the neutrophil lymphocyte ratio (r = 0.68, p = 0.001, 95% CI [0.31-1.05]). Conclusions: MDSC concentrations in metastatic prostate cancer patients are significantly higher than those with localized disease and are associated with an increased neutrophil lymphocyte ratio. Although a trend was detected towards MDSC% predicting PSA-P, in this limited sample it was not statistically significant.

MDSC clinical assay for cancer detection and monitoring in renal cell carcinoma

TPS713

Background: Human Myeloid Derived Suppressor Cells (MDSCs) have gained recognition as a significant population of cells that arise in cancer patients to mediate immune tolerance. Some studies have shown MDSC concentrations to be associated with overall survival and response to therapy in renal cell carcinoma. MDSCs comprise a heterogenous population that are yet to be fully characterized. We have identified a set of biomarkers uniquely expressed by the suppressive human MDSC phenotype and have developed an assay targeted to these markers. MDSCs are potentially a relatively cheap and easily performed screening and monitoring tool in cancers. This study will examine how a proprietary clinical assay works in detecting and monitoring MDSCs in blood and urine samples from patients with localized or metastatic renal cell cancer. Methods: The pilot research trial will enroll 63 subjects in a 1:1:1 ratio in three groups, normal controls over age 40 without evidence of any malignancy, patients with metastatic disease and localized renal cell carcinoma prior to nephrectomy. This sample size provides 80% power to detect a 1SD difference in MDSC concentrations in these groups on an F test. Blood and urine samples will be drawn at baseline and at 4 months for comparison. The percent CD33+ HLA-DRlow HIF1a+, CD33+ HLADRlow C/EBPb+, CD11b+ HLA-DRlow HIF1a+, and CD11b+ HLA-DRlow C/EBPb+cells as a fraction of PBMC will be determined. Primary Outcome Measures will be 1. Change in MDSC levels in patients with known localized renal cell carcinoma who undergo surgical treatment. 2. Change in MDSC level in patients with known metastatic renal cell carcinoma who initiate systemic treatment and 3. The direction and magnitude of the changes compared with radiographically assessed tumor burden. Secondary outcome measures are to assess MDSC level measurements in urine cytology analysis at baseline and after treatment to determine whether the two tests correlate in any of the 3 groups of patients defined in this study. Conclusion: This pilot study will examine if a MDSC clinical assay works in detecting and monitoring MDSCs. Recruitment is open to patients at the USC Cancer center and LAC+USC medical center. Clinical trial information: NCT02664883.

Immune checkpoint molecule expression measured using circulating cell-free RNA isolated from the blood of metastatic prostate cancer patients

380

Background: Recent studies have identified panels of immune-related genes linked to progression and survival. Expressions usually are measured using RNA from tissue samples. The aim of the present study was to utilize circulating RNA (cfRNA) isolated from hormone-naïve (HN) and castrate-resistant prostate cancer (CRPC) patients to measure gene expressions of PD-L1, cytotoxic T-lymphocyte associated protein 4 (CTLA-4), T-cell immunoglobulin and mucin domain 3 (TIM-3) and lymphocyte activated gene 3 (LAG-3). Androgen receptor (AR) and AR-variant 7 (AR-v7) expressions were also measured in these samples to test for any possible relationships with the immune checkpoint genes. Methods: Blood samples were collected from 53 metastatic prostate cancer patients. cfRNA was extracted from patients’ plasma and reverse transcribed into complementary DNA. The gene expressions (mRNA levels) of the above genes were determined by quantitative reverse transcription-PCR. Beta-actin was used to normalize gene expressions to total RNA content. Results: Each of the immune signatures tested (PD-L1, TIM-3, LAG-3, CTLA-4) was expressed in over 50% (29/53) of the patients’ blood samples. AR was expressed in 25/53 (47%) samples. Four of these patients (8%) expressed AR-v7, indicating resistance to anti-AR drugs. Patient disease status included: 25% (13/53) CRPC, 74% (39/53) HN, and 1 unknown. Within the CRPC group, a significant negative correlation was found between TIM-3 and CTLA-4 expression (-0.833), and CTLA-4 also correlated with disease progression (0.719). Within the HN group, a significant negative correlation was measured between TIM-3 and PD-L1 (0.589). AR expression did not correlate with other targets measured among all patients or within the CRPC or HN groups. Conclusions: This study demonstrates successful quantitation of immune checkpoint gene expressions as well the AR and AR-v7 genes in plasma of prostate cancer patients. This result opens the possibility of the use of a noninvasive method to measure, monitor and track the dynamic interplay of these genes with changing disease status. Clinical trial information: NCT02853097.

MDSC clinical assay for cancer detection and monitoring in urothelial carcinoma

TPS110

Background: Human Myeloid Derived Suppressor Cells (MDSCs) have gained recognition as a significant population of cells that arise in cancer patients to mediate immune tolerance. Some studies have shown MDSC concentrations to be associated with overall survival and response to therapy in urothelial carcinoma. MDSCs comprise a heterogenous population that are yet to be fully characterized. We have identified a set of biomarkers uniquely expressed by the suppressive human MDSC phenotype and have developed an assay targeted to these markers. MDSCs are potentially a relatively cheap and easily performed screening and monitoring tool in cancers. This study will examine how a proprietary clinical assay works in detecting and monitoring MDSCs in blood and urine samples from patients with or without localized or metastatic bladder cancer. Methods: The pilot research trial will enroll 63 subjects in a 1:1:1 ratio in three groups, normal controls over age 40 without evidence of any malignancy, patients with metastatic disease and localized muscle invasive disease prior to cystectomy. This sample size provides 80% power to detect a 1SD difference in MDSC concentrations in these groups on an F test. Blood and urine samples will be drawn at baseline and at 4 months for comparison. The percent CD33+ HLA-DRlow HIF1a+, CD33+ HLADRlow C/EBPb+, CD11b+ HLA-DRlow HIF1a+, and CD11b+ HLA-DRlow C/EBPb+cells as a fraction of PBMC will be determined. Primary Outcome Measures will be 1. Change in MDSC levels in patients with known localized, muscle-invasive bladder cancer who undergo neoadjuvant and surgical treatment. 2. Change in MDSC level in patients with known metastatic bladder cancer who undergo systemic treatment and 3. The direction and magnitude of the changes compared with radiographically assessed tumor burden. Secondary outcome measures are to assess MDSC level measurements in urine cytology analysis at baseline and after treatment to determine whether the two tests correlate in any of the 3 groups of patients defined in this study. Conclusion: This pilot study will examine if a MDSC clinical assay works in detecting and monitoring MDSCs. Recruitment is open to patients at the USC Cancer center and LAC+USC medical center. Clinical trial information: NCT02735512.

Impact of timing of administration of bone supportive therapy on pain palliation from radium-223

5023

Background: Skeletal-related events (SREs) drive morbidity in patients with metastatic castration-resistant prostate cancer (mCRPC). In the ALSYMPCA study, Radium-223 (Ra223) was found to palliate pain in addition to prolonging survival and reducing SREs. Earlier onset of pain relief was noted when zoledronic acid (ZA) was administered within 24-48 hours of samarium; we evaluated whether the timing of bone supportive therapy (BST) affected pain palliation fromRa223. Methods: We identified patients who received Ra223 at University of Southern California or Mayo Clinic Arizona. Data extracted: Ra223 administration dates, pain scores, pain medications, ZA or denosumab administration dates, alkaline phosphatase (ALP) levels, prostate specific antigen (PSA) levels, and concurrent prostate cancer therapy. Patients were evaluable for pain response if they had at least 2 pain scores documented before and after Ra223 with pain medication use data. Pain response was defined as > 2 point decrease in pain on a 10 point scale; flare was defined as > 2 point increase followed by return to baseline or lower. Results: Of 65 patients, 20 had baseline pain score > 0 and 34 were evaluable. Median #doses Ra223 was 5 (range 2-6). 18 patients received concurrent abiraterone (abi) or enzalutamide (enza), 16 did not. Pain response occurred in 6/6 (100%) patients who received BST within 1 month prior to first Ra223 dose and 4/8 (50%) patients who did not receive BST. Pain flare occurred in 6/21 patients (29%) without BST and 2/13 (15%) with BST. 6/10 (60%) patients with pain response had ALP decline but there was no consistent pattern of ALP changes in patients with flare. 8/8 patients with pain response had no PSA decline (6 increased, 2 stable). 6/12 (50%) and 2/22 (9%) patients on abi/enza had pain response and flare respectively, and 4/8 (50%) and 6/19 (32%) patients without concurrent abi/enza had response/flare. Conclusions: BST within 1 month prior to first Ra223 may be associated with increased likelihood of pain palliation and may prevent pain flare. PSA/ALP changes do not predict pain response. Concurrent use of abi/enza does not increase the likelihood of pain response and may decrease the likelihood of flare.

Impact of resistance exercise on metabolic syndrome (MetS) parameters in men receiving androgen deprivation therapy (ADT) for prostate cancer

223

Background: Cardiovascular disease is the leading cause of death in men with prostate cancer. ADT is effective treatment, but can induce loss of skeletal muscle, plus increase central fat, lipids, and insulin resistance. These changes in MetS components may contribute to excess cardiac risk. We tested whether a resistance exercise program, designed to increase skeletal muscle mass, could offset adverse changes in MetS parameters during ADT. Methods: Men on ADT for at least 12 weeks were randomized to exercise (EX) or no exercise (NOEX). EX was supervised, periodized resistance training followed by stretching 3x/week for 12 weeks, 45 min/session. NOEX did home-based stretching 3x/week. Baseline and post-intervention measurements included weight, waist circumference, lean body mass, lipids, insulin, glucose, hsCRP. Quality of life (QOL) was evaluated with FACT-P and BFI, and muscle biopsies were obtained pre- and post-intervention. Mean of changes from baseline were compared between groups using ANCOVA. Results: 24 men (mean age 65; range 49-81) completed protocol with 100% compliance (n = 12 EX, n = 12 NOEX). Baseline PSA ranged from 0 – 8.1 ng/mL and did not change; subjects had been on ADT for a mean of 17 months (range 3-84). In multivariable analysis controlling for baseline muscle mass, age, and ADT duration, the mean change in waist circumference after 12 weeks was significantly different between EX (-2.05 cm +/- 2.82) and NOEX (+0.69 cm +/- 2.01) groups (p = 0.011, t-test). There were no significant differences for other parameters. However, consistent patterns were noted in: mean fasting glucose -4.59 mg/dL in EX compared with +1.12 mg/dL in NOEX (p = 0.21, t-test) and diastolic blood pressure -2.17 mmHg in EX vs +2.0 mmHg in NOEX (p = 0.27, t-test). In the EX group 5/12 had MetS at baseline which remained stable while the NOEX group increased from 2/12 with MetS at baseline to 3/12 post intervention. Analysis of QOL and muscle biopsies are ongoing. Conclusions: Supervised resistance exercise for 12 weeks is feasible and decreases waist circumference in men receiving ADT for prostate cancer. Longer follow-up may reveal additional impacts of resistance training on MetS. Clinical trial information: NCT01909440.

Randomized phase II trial of abiraterone +/- dasatinib for patients with metastatic castration-resistant prostate cancer (mCRPC)

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Background: Signaling via Src pathway is thought to be a mediator of resistance to androgen targeted therapy in mCRPC. We sought to determine whether adding the Src inhibitor dasatinib (Das) to abiraterone (Abi) would prolong progression free survival (PFS). Methods: Eligible patients had mCRPC which had progressed on androgen targeted therapies but no prior chemotherapy. Abi was prescribed at 1000 mg daily with prednisone 5 mg BID (both arms) and Das 100 mg daily added for Arm B. Primary endpoint was PFS at 24 weeks. Interim analysis planned after 48 subjects randomized but study terminated early due to lack of funding. PFS was evaluated using logrank testing and responses were compared using Fisher’s exact test. Circulating tumor cells (CTC) were evaluated with EPIC platform. Results: 26 men were randomized, 14 to Abi+Das and 12 to Abi. Median age was 67 (56-85), baseline PSA 19.8 (0.84-1387). Only 1 patient had received ketoconazole, none had received enzalutamide. With 30 months median follow-up, median PFS was 15.7 (95% CI:8.2, 31.1+) months for Abi+Das and 9 (95% CI: 4.4, 45.6+) months for Abi (p = 0.30). 86% were progression free at 24 weeks with Abi+Das compared to 75% on Abi. RECIST responses were seen in 5/14 (35%, 95% CI: 17%, 66%) with 2 CR on Abi+Das and 1/12 (8%, 95% CI (0%, 37%) on Abi (p = 0.16). With a specificity of 83%, the probability that the true rate of CR in intervention arm is higher or doubled (ex: 35% vs 17%) is 71%. Grade > 3 toxicities more common on Das arm included hypertension (43% vs 8% Abi), pleural effusion/dyspnea (14% vs 0 Abi), and gastrointestinal (25% vs 8%). CTC were detected at baseline in 8/17 evaluable patients (3/8 Abi, 5/9 Abi+Das), median 2.7 CTC/mL blood (range 0.5-59.7) At week 4, CTC increased in 1/8 (12.5%) on Abi vs 4/9 (44.4%) on Abi+Das but by week 12 CTC increases persisted in 2/8 (25%) on Abi and 1/9 (11%) on Abi+Das. Conclusions: Das did not significantly prolong PFS in combination with Abi although power was limited due to incomplete study cohort. Abi+Das was associated with robust objective responses including RECIST CR. Clinical trial information: NCT01685125.

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.

Single arm phase II study of docetaxel and lapatinib in metastatic urothelial cancer: USC trial 4B-10-4

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Background: Advanced urothelial cancer progressing after first line systemic therapy is fatal. No agent in the second line or later setting has demonstrated improved survival although taxanes, pemetrexed, gemcitabine & vinflunine have activity & are used as palliative therapy. The Her2 pathway is up-regulated in some urothelial cancers and Her2 targeted therapy has enhanced chemotherapy effect in other cancers. We tested docetaxel with lapatinib, a Her1/Her2 TKI in urothelial cancer patients. Methods: Pts with measurable or evaluable urothelial cancerentered a single arm 2-stage phase II clinical trial, with PFS rate at 12 weeks as the primary endpoint in a Simon 2-stage design of 14+26 patients. The goal was a 12 week non progression rate of 60% - seen as promising compared to a rate of < 40% seen as not. In a 2-stage design if ≥ 6 of 14 patients had not progressed by 12 weeks the trial would continue to 40 pts. Secondary endpts: ORR, safety & OS. First 6 patients were given lapatinib 1250mg PO daily & docetaxel 60mg/m2 IV q3wk; docetaxel dose then increased to 75mg/m2 q3wk. Tumor tissue & circulating microenvironment were evaluated. Results: From July 2011 to July 2013, 15 pts were accrued. Median age 65 y, male 80%, ECOG 0 73%, Caucasian 73%, Mets: Liver 20%, Lung 20%, Bone 20%. PFS at 12 weeks 40%+/-13% - the trial was terminated after first stage. Reason off therapy: PD 10 (67%), toxicity 4 (27%). RECIST 1.1 best response: CR 1 (8%), SD 4 (31%), PD 8 (62%). Median OS: 6.3 (2.2, 12.7), PFS 2.0 (1.3, 6.6) months; 2 pts alive, follow up at 6.9 & 8.1 months. Common toxicities: diarrhea 80% (gr3 33%), vomiting 40% (gr3 26.7%), nausea 67% (gr3 26.7%) & fatigue 73.3% (gr3 6.7%). Conclusions: This phase II study of docetaxel with lapatinib in advanced urothelial cancer patients failed to provide sufficient efficacy for us to complete full accrual. One patient had a complete response and molecular correlatives may shed light on what may have predisposed to this. Intercurrently, another trial of maintenance lapatinib or placebo after chemotherapy in Her2+ patients reports no benefit (Powles ASCO 2015). Lapatinib alone or in combination is not recommended as therapy in urothelial cancer patients unless new tractable markers of response are developed. Clinical trial information: NCT01382706.

Association of ARV7 expression with molecular and clinical characteristics in prostate cancer

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Background: Prostate cancer (PC) is the most common cancer in men over the age of 60 and the second leading cause of cancer mortality in the United States. Clinicopathological parameters such as Gleason score, tumor volume, surgical margins, prostate-specific antigen (PSA), Ki-67 index and clinical stage are used as prognostic markers for clinical outcomes. Identification of novel molecular markers could improve our understanding of the clinical behavior of this disease. Androgen receptor isoforms, in particular variant 7 (ARV7 or AR3) have been recently studied for elucidating their potential role in PC progression, associated with epithelial-mesenchymal transition (EMT), disease aggressiveness, increased proliferation and therapeutic resistance. Our study is analyzing the association of ARV7 mRNA expression to clinical characteristics and is analyzing the genomic data to identify differentially altered genes by ARV expression status, summarized as a potential functional network. Methods: We obtained the TCGA public dataset of prostate adenocarcinoma tumors (N=499) that included the clinical data, gene and isoform expression and mutation data. Cases were categorized into ARV7 over-expressing (ARV+) and normal or low expression (ARV –/N) by using a cut-off of upper 25th percentile of the background genomic expression. Analysis was performed in R and Perl by using custom-made scripts. Differentially altered genes and pathways were identified and were summarized as potential functional networks. Results: We categorized 30 out of the 499 tumors as ARV+. ARV7 over-expression was found to be significantly associated with older age at diagnosis (>70), advanced clinical stage, nodal involvement, high Gleason score and a poor therapeutic response. We also observed a trend towards shorter disease-free survival among ARV+ tumors. In addition, ARV+ tumors showed significantly higher number of mutations in 20 key regulatory pathways including Jak-STAT signaling, homologous recombination, ErbB and Wnt signaling pathways. Conclusions: ARV7 overexpression is associated with genomic alterations in key regulatory pathways and poorer clinical outcome in PC patients.

Angiogenic markers during bevacizumab-based treatment in metastatic renal cell carcinoma (RCC)

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Background: Targeting the vascular endothelial growth factor (VEGF) pathway delays progression in mRCC, however innate and acquired resistance limit success. CD105 (endoglin) is a TGFb family receptor which is upregulated after VEGF inhibition, possibly mediating resistance. We studied serum CD105 and TGFb at baseline and after treatment, and tissue levels of TGFbR1 & 2 plus AVCRL, to discover biomarkers for treatment response as part of a randomized trial of bevacizumab (Bev) +/- the anti-endoglin antibody TRC105. Clinical data from the trial were presented at ASCO 2015 (Dorff et al, abstr 4542). Methods: Serum was collected at baseline and before cycles 2&4. ELISA was performed using kits from Abcam. Changes from baseline were evaluated and compared overall and between arms using a general linear mixed effects model. Immunohistochemistry was performed on paraffin embedded tissue samples using antibodies from R&D systems; tissue and baseline ELISA data were evaluated for association with PFS using Kaplan-Meier analysis and the logrank test. Results: 54 subjects (24 on Bev and 28 on Bev+TRC105) had at least one analyzed serum sample; 14 and 19 respectively had both baseline and cycle 2 samples. Mean CD105 was 82.8 (95%CI 64.6, 106.2) at baseline and 59.0 (95%CI 43.2, 80.7) at cycle 2; for 16 patients with cycle 4 data the mean was 39.8, significantly lower than baseline (p = 0.024), but not different between treatment arms. Cycle 2 TGFb levels were not different from baseline (p = 0.66) or between arms (p = 0.17). Baseline serum TGFb below the median ( < 10.6) was associated with higher likelihood of PFS at 12 and 24 weeks; (0.78 vs 0.3 and 0.49 vs 0.19, respectively, p = 0.022); baseline CD105 was not (p = 0.83). Tissue was available for 29 subjects. No tissue markers (TGFbR1 &2 or AVCRL) were associated with longer PFS except, in exploratory analysis, higher TGFbR2 staining in patients treated with TRC105 (p = 0.017). Conclusions: No pharmacodynamics markers for TRC105 therapy were identified. Lower baseline serum TGFb levels may be prognostic of PFS during Bev therapy, supporting the notion that this pathway contributes to resistance. Better PFS in TRC105-treated patients with higher tissue TGFbR2 expression warrants further study. Clinical trial information: NCT01727089.

Randomized phase I/II trial of two schedules of bortezomib and bevacizumab (BBmibmab) in metastatic renal cell cancer: USC trial 4K-05-1

574

Background: VEGF agents are a mainstay of therapy in advanced RCC. Bev has activity in RCC but was licensed with interferon-α, which can produce side effects and reduced QoL. Based on non-overlapping side effect profiles, we studied bortezomib (Bmib), a proteasome inhibitor, with the VEGF ligand monoclonal antibody, bevacizumab (Bmab). Primary objective was to examine safety/toxicity of 2 dose schedules of Bmib with Bmab with secondary aims of efficacy (benchmarked to NCI data) and correlatives. Methods: From 2005 and 2014, 62 RCC patients with clear cell or papillary predominant histology treated with 0-4 prior therapies were screened: 10 screen failed, 4 were ineligible (2 treated, 2 not) leaving 48 eligible patients, of whom 46 were evaluable for safety and efficacy endpoints with 20 in each of the phase II dose schedules. Regimens were randomly allocated, stratified by MSKCC group. Results: Best tolerated doses of Bmib with Bmab 10mg/kg IV q3wks on each regimen were A: 1.3 mg/m2 on D 1, 4, 8 and 11 q3wks & B: 1.8 mg/m2on days 1 and 8 q3wks. MSKCC strata: low, intermediate, high risk in 43, 42%; 48, 49%; 9, 9% for schedules A and B, respectively; other baseline factors were not significantly different between A & B. Overall: nephrectomy 90%; ECOG 0 73%; male 71%; median age 57 years; Caucasian 48%, Hispanic 33%, Black 8%, Asian 10%;. Median cycles both arms: 5. Best RECIST 1.0 response PR: 13%, 13%; SD 52%, 48%; PD 26%, 35%; Reason off therapy: PD 58, 67%; toxicity 25, 17% in arms A, B. Median OS: 33.4, 14.7 months (p=0.69), TTP 11.2, 9.4 months, PFS 7.3, 6.6 months (p=0.61) in arms A, B. Grade 3+ tox: A 14/24 vs. B 13/24, p=1.0. Arm A had numerically more skin toxicities and grade 2/3 hematological tox (Plats and WBCs) compared to arm B but this was not statistically significant. Conclusions: Randomized comparisons of novel agents are feasible in renal cell cancer using risk factor algorithms. This VEGFrTKI contemporaneous series of Bmab based therapy with 2 schedules of Bmib suggests potential better outcomes for schedule A with more frequent dosing of Bmib – further sensitivity analysis is ongoing to determine whether this is explained by histology or therapeutic sequencing or likely to suggest proteasome as a target in RCC. Clinical trial information: NCT00184015.

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.

A Phase II trial of a combination herbal supplement for men with biochemically recurrent prostate cancer

BACKGROUND

Men with biochemical recurrence (BCR) of prostate cancer are typically observed or treated with androgen-deprivation therapy. Non-hormonal, non-toxic treatments to slow the rise of PSA are desirable. We studied a combination herbal supplement, Prostate Health Cocktail (PHC), in prostate cancer cell lines and in a population of men with BCR.

METHODS

PC3, LAPC3 and LNCaP cells were incubated with increasing concentrations of PHC suspension. Men previously treated for prostate cancer with surgery, radiation or both with rising PSA but no radiographic metastases were treated with three capsules of PHC daily; the primary end point was 50% PSA decline. Circulating tumor cells (CTCs) were identified using parylene membrane filters.

RESULTS

PHC showed a strong dose-dependent anti-proliferative effect in androgen-sensitive and independent cell lines in vitro and suppression of androgen receptor expression. Forty eligible patients were enrolled in the clinical trial. Median baseline PSA was 2.8 ng ml(-1) (1.1-84.1) and 15 men (38%) had a PSA decline on study (1-55% reduction); 25 (62%) had rising PSA on study. The median duration of PSA stability was 6.4 months. Two patients had grade 2/3 transaminitis; the only other grade 2 toxicities were hyperglycemia, hypercalcemia and flatulence. There were no significant changes in testosterone or dihydrotestosterone. CTCs were identified in 19 men (47%).

CONCLUSIONS

Although the primary end point was not met, PHC was well tolerated and was associated with PSA declines and stabilization in a significant number of patients. We believe this is the first report of detecting CTCs in men with BCR prostate cancer. Randomized studies are needed to better define the effect of PHC in men with BCR.

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.

Identification of biologic and inflammatory markers for predicting clinical responses to sipuleucel-T in CRPC

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Background: Sip-T prolongs OS in asymptomatic or minimally symptomatic CRPC. We prospectively evaluated biomarkers in men receiving Sip-T to identify predictors of SDP and OS. Methods: Circulating tumor cells (CTC), PSA, prostatic acid phosphatase (PAP), albumin (Alb), hemoglobin (Hb), serum alkaline phosphatase (SAP), LDH, C-reactive protein (CRP) and β2-microglobulin (β2m) were evaluated in a reference lab. SipT product parameters, CD54, CD54 upregulation (UPREG) and total nucleated cells (TNC) were measured by Dendreon. Survival was evaluated using Kaplan-Meier estimates; univariate Cox regression was used to investigate the effect of biomarkers on SDP and OS using 2-sided tests and corrected for multiple comparisons. Results: 92 men who received Sip-T were included. Median age was 69 (48-90). The median follow-up was 14 (1.3 –34.7) mos, and 33% of men had died. 21 men developed SDP at a median of 5.7 (1-19) mos. Univariate analyses of biomarkers and product parameters are shown in the table. In multivariate analysis independent risks factors were LDH (p=.04) and β2m (p=.004) for SDP; LDH (p=.04), PSA (p=.012), age (p=.012) and UPREG (p=.006) for OS. Conclusions: CTC, CRP, LDH are associated with outcomes after Sip-T, similar to findings with hormone or cytotoxic therapy. Correlation of improved OS with low PSA and higher Hgb, albumin and Sip-T immune parameters supports the hypothesis that SipT is more effective with low disease burden. Prediction of early disease progression by β2m and LDH warrants further study. [Table: see text]

Clinical and biologic factors for immune response to sipuleucel-T (SipT) for metastatic castrate-resistant prostate cancer (mCRPC)

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Background: SipT prolongs overall survival of men with asymptomatic or minimally symptomatic mCRPC. Recently, it has been demonstrated that SipT immune parameters correlate with survival. We prospectively collected biological and inflammatory markers as part of an audit to identify possible predictors of immune response in patients (pts) receiving SipT. Methods: Circulating tumor cells (CTC), PSA, prostatic acid phosphatase (PAP), albumin (Alb), hemoglobin (Hb), serum alkaline phosphatase (SAP), LDH, C-reactive protein (CRP) and β2-microglobulin (β2m) were evaluated in reference lab before SipT. Product parameters CD54, CD54 upregulation (UPREG) and total nucleated cells (TNC) were measured by Dendreon. These datasets were analyzed using Spearman coefficients for continuous variables and the Kruskal-Wallis test for categorical variables. Results: 92 pts who received SipT were included. Median age was 69 (48-90). 43% had Gleason 8-9. 42% had ECOG Performance Status (PS) 0, 44% PS 1, and 13% PS 2. 26% had received prior chemotherapy and 18% had used opioids. 84% had bone mets, 42% had lymphadenopathy, 12% had visceral mets. Of clinical factors only PS was inversely correlated with UPREG (p=0.014) and TNC (p= 0.023). Biomarkers which significantly correlated with SipT immune parameters are shown in the Table. Age, location of mets, prior chemotherapy or opioid use did not impact the immune response to SipT Conclusions: Better product parameters correlated with good ECOG PS, lower PSA and SAP, and higher Hgb and Alb, suggesting that SipT induces a greater immune response in men with lower disease burden. The correlation of increased CD54 count with lower CRP, a surrogate for IL-6 activity, warrants investigation. [Table: see text]

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.

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

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.

Final results from a trial of a combination herbal supplement for biochemically recurrent prostate cancer

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Background: No standard exists for the treatment of bcrPC. Concern over deleterious effects of androgen deprivation (ADT) and lack of proven survival benefit in this setting makes initiation of ADT inappropriate for some patients. A non-hormonal, non-toxic agent to reduce PSA would be a welcome alternative to observation. We tested Prostate Health Cocktail (PHC), a supplement containing vitamin D & E, saw palmetto, lycopene, green tea and soy extracts, in this population, to see whether it could decrease PSA. Methods: Eligible men had a rising PSA with doubling time between 3 and 36 months, with no evidence of metastases on CT and bone scan. After IRB approval, 40 men were treated with PHC 3 capsules PO daily for 4 week cycles. PSA was repeated after cycle 1, then every 2 cycles thereafter with imaging only as clinically indicated; the primary endpoint was PSA decline. PSA progression was defined as 25% increase above baseline/nadir AND absolute increase of 5 ng/mL or return to baseline. Circulating tumor cells (CTCs) were measured at baseline and after 3 cycles using parylene membrane filters. Results: 60 men screened, 17 failed (28%). Median age was 67 (range 54-84) and baseline PSA 2.8 ng/mL (1.1-84.1). 23% had primary radiation only, 25% had prostatectomy, and 52% had both; 23% had Gleason 8-10. The median # of cycles was 8 (1-13). 15/40 men (37.5%) had a PSA decline (1.1%-55% maximum decrease). 43% stopped therapy for PSA progression, with median time to progression 10.2 months. Circulating tumor cells were detected in 5 of the first 23 subjects; complete CTC data will be presented. There was no significant change in testosterone or DHT during treatment. Toxicities possibly related to PHC included grade 1 or 2 liver enzyme elevations [transient], grade 1 or 2 gastrointestinal symptoms (9), grade 1 weakness/dizziness/pain (5), and grade 1 fatigue (2). 5 men continue on study, 3 lost to f/u, 16 have developed metastases, median time to mets 31.5 months from bcr. Conclusions: PHC induced PSA declines in 37% of patients with bcrPC, and was not associated with changes in serum androgens or significant toxicities. PHC is a potential alternative to observation in select patients with bcrPC. Clinical trial information: NCT00669656.

Sequential monitoring of androgen receptor expression and copy number variation in castration-resistant prostate cancer (CRPC)

11047

Background: The high-definition circulating tumor cell (HD-CTC) assay provides for an enrichment-free approach to identify and characterize CTCs. Here, we utilized the HD-CTC assay to study androgen receptor (AR) expression combined with single-nucleus sequencing for genome-wide analysis of copy number variation (CNV) in sequential samples obtained from patients with CRPC treated with abiraterone acetate (AA). Methods: Patients were approached for participation in a study to provide peripheral blood at baseline, at 2-5 weeks, and at 9-12 weeks (or at progression). In each sample, 106cells (defined with a DAPI-intact nucleus) were quantitatively examined for the presence of cytokeratin and AR (CTCs) and CD45 (leukocytes). Initial results are available from 9 subjects treated with AA as standard of care. Results: At baseline, the median (range) CTC was 7.8 (1.1-57.2) cells/ml. Using a definition of AR positive (AR+) as >6 standard deviations over mean signal observed in leukocytes, the median (range) of AR+ and total CTCs observed at baseline were 3.1(0-33.8) and 7.8 (1.1-57.2) cells/ml, respectively. Detailed single-nucleus CNV analysis was performed in sequential samples in a single subject (Table). Complex genomic rearrangements were observed including AR amplification and 8p deletion in both AR+ and AR- negative (AR-) cells at baseline. During AA treatment, the frequency of AR+ CTCs decreased along with changes in the CNV pattern including loss of AR amplification. At 10 weeks, disease progression occurred coincident with re-emergence of an AR+ CTC population exhibiting AR amplification and a novel CNV pattern only distantly related to that of the baseline CTCs. While multiple complex abnormalities were noted, MYC amplification was observed at higher frequency in cells present at progression. Conclusions: Overall, our results demonstrate the feasibility of monitoring of CTCs for treatment emergent changes in protein which may be used to better monitoring and predict therapeutic responses in patients with metastatic cancer. [Table: see text]

Quality of life in patients receiving herbal therapy for biochemically recurrent prostate cancer

e16073

Background: Men who experience biochemical recurrence after curative therapy for prostate cancer are often treated with androgen deprivation therapy (ADT), though there is no proven survival benefit in this setting. Side effects of ADT negatively impact quality of life (QOL). There is interest in alternative therapies to control PSA without ADT side effects. In conjunction with clinical testing of prostate health cocktail (PHC), a combination herbal therapy for men with biochemically recurrent prostate cancer, we surveyed QOL in trial subjects who were still receiving PHC (n=11), or had moved on to ADT (n=12) or observation (n=16). Methods: Subjects were surveyed using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) instrument, in which respondents report their level of physical and psychological functioning during the past 7 days. The survey was completed in person, by phone, by mail or via online submission. Results: Of the 40 men (93% of total trial subjects) who responded to the survey, the median age was 66 (range 54-84) and PSA was 2.8 (range 1.1-84). 23% had received radiation as primary treatment, 25% radical prostatectomy, and 52% had received both. One patient was receiving radiation at the time of survey and was excluded. In the Physical Well-Being domain, which assesses energy, feeling ill, nausea, pain and trouble meeting needs, there was a significantly lower score among men receiving ADT (median 25; 95% CI 23.5-26.2) compared to those taking PHC (26.5; CI 24.2-27.8) or being observed (28; 26.4-28) (p =0.006). There was no significant difference among the groups in the other domains, though within the Prostate Cancer-Specific Concerns domain significantly more men indicated they were "not at all" able to have/maintain erections in the ADT group (11/12) compared to PHC (6/11) and observation (5/15) (p=0.009). Conclusions: Decisions about treatment for rising PSA levels after curative-intent therapy must be informed by therapeutic value as well as consideration for QOL. We found that men being treated with ADT have a significantly lower physical function score, and the relatively high QOL for patients on a clinical trial of an herbal supplement was similar to that of patients being observed. Clinical trial information: NCT00669656.

A phase II trial of the aurora kinase A inhibitor MLN8237 in patients with metastatic castrate resistant and neuroendocrine prostate cancer

TPS5096

Background: NEPC can rarely arise de novo but more commonly arises as a mechanism of resistance in the setting of advanced prostate cancer. Transformation to NEPC is likely promoted by potent hormonal therapies and is currently under-recognized. There is no effective therapy for NEPC and most patients (pts) survive less than one year. We have found that Aurora kinase A (AURKA) and N-myc (MYCN) are significantly overexpressed and amplified in NEPC compared to prostate adenocarcinoma, and cooperate to induce neuroendocrine (NE) differentiation in prostate cancer (Beltran et al, Cancer Disc 2011). In preclinical models, aurora kinase inhibition results in dramatic and preferential anti-tumor activity in NEPC. Methods: In this single arm, multi-institutional Phase II trial, pts with metastatic prostate cancer need to meet at least one NEPC entry criterion: 1) histologic diagnosis of small cell or NEPC, 2) >50% immunohistochemical staining for NE markers, 3) development of liver metastases in absence of PSA progression, or 4) serum chromogranin >5x normal or neuron specific enolase >2x normal. Study will be open at 10 institutions including PCCTC sites. After a mandatory on-study research biopsy, pts will be treated with MLN8237, an orally administered Aurora kinase A inhibitor at 50 mg twice daily for 7 days repeated every 21 days. The primary endpoint is objective response rate (ORR). Secondary endpoints include overall survival, progression free survival, PSA response rate, circulating tumor cell response, and serum NE marker response to therapy. A number of correlative studies including AURKA, MYCN, AR, and exome and RNAseq are embedded in this trial in order to molecularly define this aggressive and poorly characterized disease. A Simon 2-stage design will be employed with up to 60 subjects providing 80% power to determine if the true ORR is >30% and 95% power if the true ORR is <15%, assuming a 5% level of significance. A subset of at least 20% meeting histologic entry criteria is embedded.

Targeted next-generation sequencing (NGS) of circulating tumor cells (CTCs) in hormone-sensitive prostate cancer (HSPC)

11040

Background: Recently a succession of new hormonal therapies has emerged, highlighting the need for biomarkers to guide the management of HSPC. Biomarker development in HSPC has been hampered by the absence of primary tumor tissue in men who undergo radiation or present with metastatic disease. CTCs can address this challenge by providing real-time cancer tissue for biomarker analysis in HSPC. To test this approach we conducted a pilot of CTC capture and targeted NGS in HSPC. Methods: Under IRB approval, blood samples from patients with HSPC were labeled with EpCAM ferrofluid and placed into the LiquidBiopsy platform (Cynvenio Biosystems, Inc.), an immunoaffinity-based microfluidic device tailored to query genomic events. CTCs were identified by CK, CD45 and DAPI expression. A matched WBC pellet served as a control representing germline sequence. Amplicon libraries were generated using Life Technologies AmpliSeq 2.0 and sequenced on an Ion Torrent platform. Somatic single nucleotide variants (SNV) present in CTCs but not in WBC were identified. Results: CTCs were detected in all 8 patients with HSPC (CTC median 64.5, range 17-217). Germline variants were consistently detected in matched CTC and WBC samples. Significant SNVs (occurring in > 1% of DNA in a sample) were found in 4 of 8 CTC samples (range 1-5 SNVs/sample, frequency 1.2%-11.9% with 620X-14,422X coverage). Notably, 3 patients had biochemical recurrence only (no clinical metastases) yet still yielded CTCs associated with SNVs in KIT, APC, RET, SMAD4 and PTEN. One patient who had untreated metastatic disease had the highest number of CTCs which harbored 4 SNVs. Conclusions: This pilot demonstrates the feasibility of using CTCs as real-time disease relevant substrate for NGS to identify personalized genomic targets in HSPC. A high number of CTCs were detectable in all patients and CTC germline variants correlated with matched WBC controls. Encouragingly, even with a relatively narrow, primary tumor-derived AmpliSeq platform, cancer relevant SNVs were detected in half of the patients including those with only biochemical recurrence, making targeted NGS of CTCs a promising approach for biomarker discovery and validation in HSPC.

A phase I dose-escalation trial of AEZS-108 in taxane- and castration-resistant prostate cancer (CRPC)

5062

Background: The receptor for luteinizing hormone releasing hormone (LHRH-R) is highly expressed on CRPC cells and is a potential therapeutic target. AEZS-108 is an LHRH-cytotoxic hybrid that covalently couples an LHRH agonist with doxorubicin. We report the completed Phase I trial of AEZS-108 in men with taxane-resistant CRPC. We explored visualization of AEZS-108 internalization into circulating tumor cells (CTCs) exploiting the auto-fluorescence of doxorubicin and also tested LHRH-R expression on CTCs. Methods: This was a dose escalation Phase I trial in men with taxane-resistant CRPC to confirm the dose established in a phase I trial in women. Standard 3+3 design was used with planned expansion at the MTD to ensure 6 patients received 2+ courses without DLT. Eligibility criteria included progression of disease despite prior LHRH agonist and taxane therapy. Patients received AEZS-108 every 21 days until progression or unacceptable toxicity. The primary endpoint was safety. CTCs were captured with a novel slot microfilter and identified by PSA and DAPI staining. AEZS-108 internalization was visualized by fluorescence microscopy. Results: Eighteen men with a median of 2 prior chemotherapy regimens (range 1-5) and a median PSA of 106.4 ng/mL (range 8.4-1624.0) enrolled from November 2010 to August 2012. The dose was escalated from 160 mg/m2 to 210 mg/m2 then to 267 mg/m2. There were 2 DLTs in the 7 men receiving 267 mg/m2 (grade 4 neutropenia), prompting de-escalation to 210 mg/m2 where 1 of 8 men experienced a DLT (grade 4 neutropenic fever), establishing 210 mg/m2 as the MTD. Significant non-hematologic toxicities included a case of grade 3 nausea. No cardiotoxicity was seen on serial evaluation and 6 patients completed 6 cycles. Internalization of AEZS-108 was consistently visualized in CTCs 1-3 hours after dosing. Maximal PSA response was stable or decreased in 8 of 18 men. Conclusions: The MTD of AEZS-108 in men with taxane-resistant CRPC is 210 mg/m2, which is below the MTD reported in women with refractory endometrial, ovarian and breast cancer. The activity of AEZS-108 was promising in this heavily pretreated population. The Phase II portion is currently accruing. Clinical trial information: NCT01240629.

Changes in circulating tumor cells (CTC) and markers of inflammation after sipuleucel-T treatment

40

Background: Sipuleucel-T (SipT) prolongs survival of men with metastatic castrate-resistant prostate cancer (CRPC). We prospectively collected CTC, LDH, and inflammatory markers as part of an audit to investigate changes after SipT treatment compared to baseline. Methods: Men with CRPC had blood drawn routinely before and after SipT treatment. CTC were run using Veridex assay. LDH, C-reactive protein (CRP) and β2-microglobulin (β2m) were measured in a reference lab. Wilcoxon Signed Rank Test was used to compare pre- and post-treatment (median 3.5 weeks after final infusion) levels. Results: 61 men received SipT at USC from June 2010 to July 2012 and were included in the analysis. Median pre-SipT PSA level was 24.9 and 47% had Gleason 8-9; 20% had received chemotherapy. 18 men had detectable CTCs pre SipT (range 1-170). CTC count declined in 7 men, increased in 6 men, and stayed stable in 2 men (3 inevaluable); in 3 cases the change crossed men over from unfavorable ( >5) to favorable count. PSA declines were noted in 10 men (16.4%) ranging from -0.5% to 99%. Change in CTC and PSA was discordant in 4 cases of 13. When CTC stayed stable PSA increased in 5 and decreased in 5 cases. Median CRP was 0.5 pre and 0.23 post SipT (p=0.025) and β2m was 1.74 pre and 2.01 post (p=0.02). Increased CRP was correlated with decreased CTC (r=0.7, p=0.003 Spearman test) but β2m changes were not (r=0.45, p=0.08 Spearman) and there was no correlation between changes in the inflammation markers and PSA decline. LDH did not change significantly. The relationship between infusion reaction, eosinophilia and inflammatory markers will be presented. Conclusions: We found that CTC counts can decline after SipT treatment, including conversion from unfavorable to favorable range, and can change independently of PSA. Correlation of CTCs with outcomes in a prospective study is warranted to explore this as a potential biomarker. [Table: see text]

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.

A phase I trial of AEZS-108 in castration- and taxane-resistant prostate cancer

e15153

Background: The prognosis for patients with castration-resistant prostate cancer (CRPC) remains suboptimal and targeted therapies should be explored. One potential target is the receptor for luteinizing hormone-releasing hormone (LHRH), which is highly expressed on prostate cancer cells. AEZS-108 is an LHRH-cytotoxic hybrid whose rational design covalently couples an LHRH agonist and the cytotoxic doxorubicin. AEZS-108 exploits the presence of LHRH receptors to target delivery of the cytotoxic. We report the phase I trial of AEZS-108 in men with taxane-resistant CRPC. We also report correlative studies of a novel circulating tumor cell (CTC) capture device that will provide enumeration of CTCs and results from AEZS-108 internalization studies that exploit the auto-fluorescence of doxorubicin in captured CTCs. Methods: This is a single-arm, dose-escalation phase I study in men with CRPC to confirm the dose established in a completed phase I trial in females. Eligibility criteria included adequate organ function and progression of disease despite prior therapy with an LHRH agonist and at least one taxane-based regimen. Patients were required to discontinue LHRH agonists to avoid receptor competition. Due to potential cardiotoxicity, patients with an ejection fraction < 50% or prior exposure to doxorubicin or mitoxantrone were excluded. Pituitary function was closely monitored. Patients received AEZS-108 every 21 days for up to 6 cycles until progression or unacceptable toxicity. The primary endpoint was safety. Results: Enrollment began in November 2010 and is ongoing. Currently, 13 patients have been enrolled. The first two planned dose levels had no dose-limiting toxicities observed. Two patients on the third dose level experienced a dose limiting toxicity. The second dose level has been reopened for expansion. There have been no cardiac or pituitary toxicities. At the time of submission, a decrease in PSA was noted in 6 of the 13 patients. Final results detailing safety, response and the suggested dose for the phase II portion will be reported. All correlative studies will also be reported. Conclusions: In general, AEZS-108 has been well tolerated. The phase II portion of the study will begin once the MTD is established.

A combination herbal supplement for biochemically recurrent prostate cancer

24

Background: After curative local therapy, thousands of men will have rising PSA as an early indicator of recurrent prostate cancer. For them, no standard of care exists, and concern over serious side effects of androgen deprivation (ADT) makes delaying ADT common. We tested Prostate Health Cocktail (PHC), which contains vitamins D & E, saw palmetto, lycopene, green tea and soy extracts, in this population, to see whether it could induce PSA declines.

Methods: Eligible men had rising PSA with doubling time (DT) 3-36 months, with no evidence of metastases on CT and bone scans. After IRB approval, 28 men were treated with PHC 3 capsules PO daily for 4 week cycles. PSA was repeated after the first cycle, then every 2 cycles with imaging only as clinically indicated; the primary endpoint was PSA decline. PSA progression was defined as 25% increase and absolute increase of 5 ng/mL or return to baseline. Circulating tumor cells (CTCs) were measured at baseline and after 3 cycles using parylene membrane filters.

Results: The median age was 67 (range 54-84) and baseline PSA was 2.9 ng/mL (1.1-53.2); the median number of cycles was 6 (1-13). Stable PSA was the best response for 23/28 men (83%) and 8/27 men (29.6%) had a PSA decline (1.1%-29.4% maximum decrease). 47% stopped therapy for progression with median time to progression=9.2 months. There was no association between Gleason score or baseline PSA, vitamin D or selenium level and PSA decline. CTCs were detected in 5 of the first 23 subjects. The median PSA for these men was 2.77 ng/mL (range 1.63-16.8). There was no significant change in testosterone or DHT during treatment. Median PSA DT at baseline was 7.8 months (range 3-36). One patient had grade 3 transaminitis in the setting of alcohol consumption, otherwise toxicities were limited to grade 1 or 2 hypercalcemia(1), hyperkalemia(2), hyperglycemia(4), flatulence(4), other GI(5), and rash(1).

Conclusions: PHC demonstrated activity in men with biochemically recurrent prostate cancer, resulting in PSA declines in nearly a third of cases, and was not associated with changes in serum androgens or significant toxicities. For the first time, we are reporting that circulating tumor cells can be detected in men with biochemical recurrence using filter technology.

A phase I trial of AEZS-108 (AN-152) in castration- and taxane-resistant prostate cancer

60

Background: The prognosis for patients with castration-resistant prostate cancer (CRPC) remains suboptimal and targeted therapies should be explored. One potential target is the receptor for luteinizing hormone-releasing hormone (LHRH-R), which is highly expressed on prostate cancer cells. AEZS-108 (AN-152) is an LHRH-cytotoxic hybrid whose rational design covalently couples an LHRH agonist and the cytotoxic doxorubicin. AEZS-108 exploits the presence of these receptors to target delivery of the cytotoxic. We report the phase I trial of AEZS-108 in men with taxane-resistant CRPC. We also report correlative studies of a novel circulating tumor cell (CTC) capture device that will provide both enumeration of CTCs and LHRH-R expression on captured CTCs as well as results from AEZS-108 internalization studies that exploit the auto-fluorescence of doxorubicin in captured CTCs.

Methods: This is a single-arm, dose-escalation phase I study in men with CRPC to confirm the dose established in a completed phase I trial in females. Eligibility criteria included adequate organ function and progression of disease despite prior therapy with an LHRH agonist and at least one taxane-based regimen. Patients were required to discontinue LHRH agonists to avoid receptor competition. Patients received AEZS-108 every 21 days until progression or unacceptable toxicity for up to 6 cycles. The primary endpoint was safety.

Results: Enrollment began in November 2010 and completed in September 2011. Twelve patients were accrued onto 3 dose levels. No DLTs have been noted. At the time of submission, a decrease in PSA was noted in 5 of the 10 evaluable patients. The grade 3 or 4 toxicities were primarily hematologic. Final reports detailing toxicity, RECIST response and PSA response will be reported. All correlative studies will also be reported.

Conclusions: AEZS-108 is well tolerated and has demonstrated early signs of antitumor activity in men with CRPC. We will report the recommended dose for the planned phase II study.

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.