Changes in tumor blood flow as measured by Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) may predict activity of single agent bevacizumab in recurrent epithelial ovarian (EOC) and primary peritoneal cancer (PPC) patients: an exploratory analysis of a Gynecologic Oncology Group Phase II study.

OBJECTIVE: To explore feasibility of measuring tumor blood flow as marker for antiangiogenic activity using DCE-MRI (Dynamic Contrast-Enhanced Magnetic Resonance Imaging) in women with recurrent EOC/PPC treated with bevacizumab. METHODS: In a phase II study, 62 patients with recurrent/persistent EOC/PPC were treated with bevacizumab (15 mg/kg IV q21 days) until disease progression. DCE-MRI was performed pre-cycle 1 and 4 of bevacizumab. Images were analyzed retrospectively by a single experienced blinded radiologist. Tumor and muscle contrast enhancement was measured by region of interest signal intensity within the same DCE-MRI images. Flow rates were obtained with concentration of dye as a function of time. Relative blood flow (RBF) was calculated as a ratio of average blood flow into tumor to muscle tissue. Associations between RBF and characteristics/outcomes were explored. RESULTS: Sixty-two patients were eligible for study. Unfortunately, only 14 (23%) patients had imaging data available for analysis at baseline and 13 of those same patients (21%) had imaging data available for analysis pre-cycle 4. The RBF distribution was similar from pre-cycle 1 to 4. RBF remained stable for the majority of the cases (median change -0.21). Baseline RBF was not significantly associated with being progression-free at 6 months, microvessel density, 17 month overall survival, tumor response, or platinum sensitivity. However, increases in blood flow rates were associated with likelihood to be progression-free at 6 months. CONCLUSION: Functional imaging of tumor blood flow is a potential research endpoint that may be explored further. Consideration should be given to timing of endpoint and standardizing the technique.

A phase II study of docetaxel plus lycopene in metastatic castrate resistant prostate cancer.

We carried out a phase II study to investigate the activity of docetaxel plus lycopene in advanced castrate resistant adenocarcinoma of the prostate. Patients were chemotherapy and biological therapy naive. Docetaxel 75 mg/m2 was given every 21 days with daily oral lycopene 30 mg. The primary endpoint was a ≥50% reduction in PSA. Secondary endpoints were median time to PSA progression, duration of response and overall survival. Thirteen patients were initiated on protocol therapy. Median age was 77 (range 55-90). Twelve patients (92%) had bone metastases. Four patients (30%) had both bone and visceral metastases. PSA response was seen in 10 patients (76.9% [95% confidence interval (CI), 46.2-94.9%]). Two patients had stable disease (SD), yielding a disease control rate of 92%. Median time to PSA progression was 8 months [95% CI, 3.5-8.7]. Median duration of response (DOR) was 7.3 months [95% CI, 4.8-13.2]. Median overall survival at 5 years was 35.1 months [95% CI 25.7-57.7]. No new safety signals were noted. No patients experienced grade 3 or above anemia. One patient (7%) experienced febrile neutropenia. A PSA response rate of 76.9% and median survival of 35.1 months compares favorably to the 45% PSA response rate and 17.4 months median survival reported for the TAX 237 trialists. While our study was limited due to small sample size, our results suggest that the combination of docetaxel and lycopene merits further study.

Anti-angiogenic effects of resveratrol mediated by decreased VEGF and increased TSP1 expression in melanoma-endothelial cell co-culture.

Resveratrol, a naturally occurring polyphenol, has been reported to be an anti-tumor and chemopreventive agent. Recent data show that it may also exert anti-angiogenic effects. We hypothesized that the anti-angiogenic activity of resveratrol may be caused by modulation of tumor cell release of thrombospondin-1 (TSP1) and vascular endothelial growth factor (VEGF) into the extracellular matrix, leading to vascular endothelial cell (VEC) apoptosis. We therefore evaluated the effects of resveratrol on melanoma cell lines co-cultured with vascular endothelial cells in monolayer and in three dimensional spheroids. We found that resveratrol stimulated isolated VEC proliferation, while it caused growth inhibition of VECs grown with melanoma cells in three-dimensional co-culture. This effect was associated with increased melanoma cell expression of tumor suppressor protein 53 and matrix protein TSP1, as well as decreased hypoxia-driven expression of hypoxia inducible factor-1α and inhibition of VEGF production.

Prospective evaluation of an in vitro radiation resistance assay in locally advanced cancer of the uterine cervix: a Southwest Oncology Group Study.

OBJECTIVES: To investigate the feasibility of performing a fresh-tissue, in vitro radiation resistance assay (IVRRA) in a cooperative group setting and to assess the association of IVRRA results with clinical outcomes. METHODS: Women with Stages IIB-IVA carcinoma of the uterine cervix without obvious para-aortic lymphadenopathy on imaging were eligible. Primary tumor biopsies were shipped to a central testing facility where agar-based cell suspensions were exposed to 300 cGy of RT ± cisplatin and cultured for 5 days. ³H-thymidine incorporation was used to determine percent cell inhibition (PCI) of test specimen compared to that of the untreated control. Tumors were considered to exhibit extreme radiation resistance (ERR), intermediate radiation resistance (IRR) or low radiation resistance (LRR) based on a standard data set from 39 previously studied specimens. Standardized doses of external beam radiation and intracavitary brachytherapy, when feasible, in addition to platinum-based chemotherapy were mandated. Progression-free survival (PFS) was the primary endpoint. Clinical response and overall survival (OS) were secondary endpoints. Clinical investigators were blinded to assay data and vice versa. RESULTS: Thirty-six patients were enrolled, but analysis was limited to 17 patients whose specimens were adequate for IVRRA. The median follow-up time among patients still alive at last contact was 40 months (range: 0-56 months). There was no association between IVRRA and response. In the Cox model, IRR/ERR tumors showed worse PFS [HR = 11.2 (95% CI 1.3-96, p = 0.03)] and worse OS [HR=11.7 (95% CI 1.4-99.6, p = 0.03)] compared to LRR tumors when IVRRA was performed with RT alone, but there were no associations between IVRRA and PFS or OS when cisplatin was added to the IVRRA. CONCLUSIONS: IVRRA (RT alone) results correlated with PFS and OS in this prospective trial, but follow-up trials are indicated to address feasibility and to confirm results in an expanded cohort. If confirmed, IVRRA could potentially direct molecular identification of novel targeted therapeutic approaches which might counteract radiation resistance.

Prognostic relevance of carbonic anhydrase-IX in high-risk, early-stage cervical cancer: a Gynecologic Oncology Group study.

OBJECTIVES: This study aimed to determine whether carbonic anhydrase-IX (CA-IX) was associated with progression-free survival (PFS) and overall survival (OS) in women with high-risk, early-stage cervical cancer treated with adjuvant pelvic radiotherapy with or without radiosensitizing chemotherapy. METHODS: CA-IX expression was detected using an immunohistochemistry assay and categorized as low when 80% tumor cells display CA-IX staining. Associations between CA-IX expression and clinical characteristics, angiogenesis marker expression, and clinical outcome were evaluated. RESULTS: High CA-IX expression was observed in 35/166 (21.1%) of cases. CA-IX expression was not associated with age, race, stage, cell type, grade, positive margins, parametrial extensions, positive lymph nodes, or lymphovascular space invasion but was associated with tumor size categorized as <2 , 2-2.9 , or >or=3 cm (high expression: 4.7% vs. 23.2% vs. 32.5%, P=0.003) and cervical invasion confined to the inner two-thirds compared with the outer third of the cervix (high expression: 6.1% vs. 23.7%, P=0.028). CA-IX expression was not associated with immunohistochemical expression of p53, CD31, CD105, thrombospondin-1, or vascular endothelial growth factor-A. Women with high versus low CA-IX expression had similar PFS (P=0.053) and significantly worse OS (P=0.044). After adjusting for prognostic clinical covariates, high CA-IX expression was an independent prognostic factor for PFS (hazard ratio [HR]=2.12; 95% confidence interval [CI]=1.13-3.95; P=0.019) and OS (HR=2.41; 95% CI=1.24-4.68; P=0.009). CONCLUSIONS: Tumor hypoxia measured by immunohistochemical expression of CA-IX is an independent prognostic factor for both PFS and OS in high-risk, early-stage cervical cancer.

Predictive and prognostic angiogenic markers in a gynecologic oncology group phase II trial of bevacizumab in recurrent and persistent ovarian or peritoneal cancer.

OBJECTIVE: Potential predictive/prognostic angiogenic markers were prospectively examined in a phase II trial of bevacizumab in epithelial ovarian cancer (EOC)/primary peritoneal cancer (PPC). METHODS: Recurrent/persistent EOC/PPC patients were treated with bevacizumab (15 mg/kg IV q21days) until disease progression. Validated-immunohistochemistry (IHC) assays were performed on pre-cycle 1/4 tumor biopsies for CD31-microvessel density (MVD), VEGF-histoscore (HS), p53-HS, and TSP1 image analysis score (IA). Pre-cycle 1/4 serum and plasma VEGF were quantified using a validated-ELISA. RESULTS: CD31-MVD and serum VEGF, evaluated pre-cycle 1 in 41/61 and 51/61 eligible patients, respectively, did not appear to be correlated. High CD31-MVD, categorized at the median, appeared to be associated with tumor response, a 13-month shorter median survival, and an increased risk of death (unadjusted hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.067-4.467). In addition, each standard deviation (SD) increase in CD31-MVD appeared to be associated with worse survival in unadjusted and adjusted analyses. IHC and plasma biomarkers did not change with bevacizumab treatment except for serum VEGF, which appeared to decrease during bevacizumab treatment. This decrease was not associated with response. High pre-cycle 1 serum VEGF, categorized at the median, was associated with 22-month shorter median survival and an increased risk of death (unadjusted HR = 2.7, 95% CI = 1.369-5.191). Categorized p53 appeared to be associated with unadjusted survival and each SD increase in TSP1-IA appeared to be associated with a decreased risk of progression in unadjusted and adjusted analyses. CONCLUSIONS: Despite the limitations in sample size and exploratory nature of the study, angiogenic markers in tumor and serum may provide prognostic value in recurrent/persistent EOC/PPC, and are being prospectively evaluated in the GOG phase III trial of carboplatin, paclitaxel and bevacizumab/placebo in previously untreated EOC/PPC.

Markers of angiogenesis in high-risk, early-stage cervical cancer: A Gynecologic Oncology Group study.

OBJECTIVES: To determine whether markers of tumor angiogenesis were associated with progression-free survival (PFS) and overall survival (OS) in women with high-risk, early-stage cervical cancer treated on a phase III trial. METHODS: One hundred seventy-three tumor specimens were analyzed by semi-quantitative immunohistochemical (IHC) staining for vascular endothelial growth factor (VEGF, pro-angiogenesis factor), thrombospondin-1 (TSP-1, anti-angiogenesis factor), CD31 (non-specific endothelial marker), and CD105 (tumor-specific endothelial marker). Tumoral histoscores (HS) were calculated for VEGF using the formula: [% cells positivex(intensity+1)]. TSP-1 specimens were categorized as negative or positive. CD31 and CD105 microvessel density (MVD) "hotspots" were counted in three 20x high-power fields. Associations between angiogenesis markers and survival were evaluated. RESULTS: TSP-1 expression was observed in 65% of cases while 66% expressed high VEGF (>or=200), 34% exhibited high CD31 (CD31>or=110) and 66% displayed high CD105 (CD105>or=28). In univariate analyses CD31 MVD, but not tumor TSP-1, was associated with improved PFS (HR=0.37; 95% CI=0.18-0.76; p=0.007) and OS (HR=0.37; 95% CI=0.17-0.79; p=0.010). After adjusting for prognostic clinical covariates, high CD31 MVD, but not TSP-1, VEGF or CD105 MVD, was an independent prognostic factor for PFS (HR=0.36; 95% CI=0.17-0.75; p=0.006) and OS (HR=0.36; 95% CI=0.17-0.79; p=0.010). CONCLUSIONS: Tumor angiogenesis measured by CD31 MVD is an independent prognostic factor for both PFS and OS in high-risk, early-stage cervical cancer. We hypothesize that this finding may be explained by improved treatment response in well-vascularized, well-oxygenated tumors.

HIF Inactivation of p53 in Ovarian Cancer Can Be Reversed by Topotecan, Restoring Cisplatin and Paclitaxel Sensitivity.

Ovarian cancer growth under hypoxic conditions results in hypoxia-inducible factor-1α (HIF1α) stabilization. HIF1α is an adverse prognostic factor that may contribute to worse outcomes via its capacity to bind to p53, potentially blocking p53-mediated apoptosis. We determined whether HIF1α-p53 binding occurred in hypoxic ovarian cancer cell lines, and if this blocked p53 transcriptional activity. Topotecan (TPT), used in the treatment of ovarian cancer, inhibits HIF1α translation via a topoisomerase-1 (TOPO1)-dependent mechanism. We examined if TPT knockdown of HIF1α restored p53 transcriptional function. TPT effects on HIF1α and p53-related transcriptional targets were assessed by PCR. Associations between TPT effects and TOPO1 expression levels were examined by Western blots and knockdown by siRNA. RNA-binding protein immunoprecipitation was used to assess if TOPO1 was resident on HIF1α mRNA. We determined if sublethal doses of TPT, used to knockdown HIF1α, reversed hypoxia-related cisplatin and paclitaxel resistance (XTT assay). Flow cytometry was used to assess HIF1α-mediated upregulation of ABCB1 and ABCB5 efflux pump expression. We found that HIF1α binding to, and inhibition of, p53 transcriptional activity in hypoxic ovarian cancer cells was associated with drug resistance. TPT-mediated downregulation of HIF1α in hypoxic cells required TOPO1 resident on HIF1α mRNA, restored p53 transcriptional activity, downregulated ABCB1/ABCB5 cell surface expression, and reversed hypoxia-related cisplatin and paclitaxel resistance. IMPLICATIONS: TPT-mediated reduction of HIF1α accumulation in hypoxic ovarian cancer cell lines restores p53 tumor-suppressor function, offering a novel approach to reverse chemoresistance. Further clinical investigation is warranted.

Reactive oxygen species: a breath of life or death?

New insights into cancer cell-specific biological pathways are urgently needed to promote development of rationally targeted therapeutics. Reactive oxygen species (ROS) and their role in cancer cell response to growth factor signaling and hypoxia are emerging as verdant areas of exploration on the road to discovering cancer's Achilles heel. One of the distinguishing and near-universal hallmarks of cancer growth is hypoxia. Unregulated cellular proliferation leads to formation of cellular masses that extend beyond the resting vasculature, resulting in oxygen and nutrient deprivation. The resulting hypoxia triggers a number of critical adaptations that enable cancer cell survival, including apoptosis suppression, altered glucose metabolism, and an angiogenic phenotype. Ironically, recent investigations suggest that oxygen depletion stimulates mitochondria to elaborate increased ROS, with subsequent activation of signaling pathways, such as hypoxia inducible factor 1alpha, that promote cancer cell survival and tumor growth. Because mitochondria are key organelles involved in chemotherapy-induced apoptosis induction, the relationship between mitochondria, ROS signaling, and activation of survival pathways under hypoxic conditions has been the subject of increased study. Insights into mechanisms involved in ROS signaling may offer novel avenues to facilitate discovery of cancer-specific therapies. Preclinical and clinical evaluation of agents that modify ROS signaling in cancer offers a novel avenue for intervention. This review will cover recent work in ROS-mediated signaling in cancer cells and its potential as a target for developmental therapeutics.

The effect of bevacizumab (Avastin) on neuroimaging of brain metastases.

BACKGROUND: Bevacizumab is FDA approved to treat colon cancer and is currently used off label for metastatic breast, kidney, and lung cancers. Bevacizumab is a monoclonal antibody that binds to, and inactivates, VEGF and is believed to be antiangiogenic. CASE DESCRIPTION: The authors report the case of a 54-year-old woman with metastatic infiltrating ductal breast carcinoma who developed left occipital and right parietal intraaxial contrast-enhancing masses on surveillance magnetic resonance imaging (MRI). After surgical resection, she was placed on bevacizumab for control of systemic disease. Six months later, a nonenhancing right occipital lesion was detected on MRI. After stopping bevacizumab therapy, the patient underwent microsurgical resection of the lesion. Histopathologic examination was consistent with metastatic breast cancer indistinguishable from her previously resected enhancing brain metastasis. Six weeks after stopping bevacizumab therapy and 3 weeks after microsurgical resection, a new contrast-enhancing mass was noted on magnetic resonance in the right temporal lobe. CONCLUSION: This case is unique in that we have neuroimaging on prebevacizumab, concurrent bevacizumab, and postbevacizumab brain metastases in the same patient with a single cancer primary, thus, assuring that alterations in neuroimaging characteristics are consistent with bevacizumab effect. As an internal control, it provides strong support for the premise that bevacizumab therapy can confound the diagnosis of brain metastases because of its effect on tumor enhancement.

Phase II study of pazopanib in combination with paclitaxel in patients with metastatic melanoma.

PURPOSE: This phase II study evaluated the safety and clinical activity of pazopanib, a potent and mutlitargeted tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptors (VEGFRs)-1, -2 and -3, platelet-derived growth factor receptor (PDGFR)-α and ß, and cKit, in combination with metronomic paclitaxel in patients with metastatic melanoma. EXPERIMENTAL DESIGN: Sixty chemotherapy-naive patients received pazopanib at a starting dose of 800 mg daily in combination with metronomic dosing of paclitaxel 80 mg/m2 weekly thrice every 4 weeks. The primary endpoint was 6-month progression-free survival (PFS) rate, while secondary endpoints included 1-year overall survival rate, RECIST response rates, progression-free survival rates and median overall survival. Prior BRAF-targeted therapy or checkpoint inhibitors were permitted. RESULTS: The 6-month PFS rate was 68%, with a 1-year OS rate of 48%. Objective response rate was 37% comprising one complete and 20 partial responses. Stable disease at 8 weeks was noted in 32 patients (55%) with an overall clinical benefit rate of 93%. Six-month median progression-free survival was 8 months and median OS was 12.7 months. The most frequently (> 15%) reported non-hematologic, treatment-related adverse events were fatigue, diarrhea, hypertension, transaminitis and peripheral neuropathy. Treatment-related non-fatal bowel perforation, a known class effect, occurred in one patient. No significant association was noted between plasma levels of pazopanib and response. CONCLUSIONS: The combination of pazopanib and metronomic paclitaxel was well-tolerated, demonstrating significant activity in metastatic melanoma. Further evaluation of this combination is warranted.

In vitro drug response and molecular markers associated with drug resistance in malignant gliomas.

PURPOSE: Drug resistance in malignant gliomas contributes to poor clinical outcomes. We determined the in vitro drug response profiles for 478 biopsy specimens from patients with the following malignant glial histologies: astrocytoma (n = 71), anaplastic astrocytoma (n = 39), glioblastoma multiforme (n = 259), oligodendroglioma (n = 40), and glioma (n = 69). EXPERIMENTAL DESIGN: Samples were tested for drug resistance to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), cisplatin, dacarbazine, paclitaxel, vincristine, and irinotecan. Biomarkers associated with drug resistance were detected by immunohistochemistry, including multidrug resistance gene-1, glutathione S-transferase pi (GSTP1), O(6)-methylguanine-DNA methyltransferase (MGMT), and mutant p53. RESULTS: In vitro drug resistance in malignant gliomas was independent of prior therapy. High-grade glioblastomas showed a lower level of extreme drug resistance than low-grade astrocytomas to cisplatin (11% versus 27%), temozolomide (14% versus 27%), irinotecan (33% versus 53%), and BCNU (29% versus 38%). A substantial percentage of brain tumors overexpressed biomarkers associated with drug resistance, including MGMT (67%), GSTP1 (49%), and mutant p53 (41%). MGMT and GSTP1 overexpression was independently associated with in vitro resistance to BCNU, whereas coexpression of these two markers was associated with the greatest degree of BCNU resistance. CONCLUSIONS: Assessment of in vitro drug response and profiles of relevant tumor-associated biomarkers may assist the clinician in stratifying patient treatment regimens.

The relationship of molecular markers of p53 function and angiogenesis to prognosis of stage I epithelial ovarian cancer.

PURPOSE: Multiple angiogenic factors may influence tumor progression and metastasis. Several are modified by the p53 gene. We sought to identify molecular markers for high-risk stage I epithelial ovarian cancers. EXPERIMENTAL DESIGN: Seventy-seven consecutive stage I epithelial ovarian cancers were evaluated for p53, CD31 microvessel density, thrombospondin-1, vascular endothelial growth factor (VEGF), p21 immunohistochemical staining, and p53 gene mutations. Molecular marker impact upon disease-specific survival, disease recurrence, and distant recurrence was evaluated with Cox regression. RESULTS: There were 12 deaths from disease. Twelve of the 77 tumors contained p53 mutations-10 missense and 3 null (one tumor had two mutations). Fesddration Internationale des Gynaecologistes et Obstetristes substage (IA/IB versus IC; P < 0.001) and VEGF staining (P = 0.02) were significant in bivariate models with relationship to disease-specific survival. Stage (P = 0.0004), grade (P = 0.008), histology (P = 0.0025), p53 dysfunction (positive stain and/or mutation; P = 0.048), and microvessel density (P = 0.04) were significant in bivariate models with relationship to time to recurrence. In multivariate analyses among stage IC patients, failure to receive chemotherapy and microvessel density were associated with disease-specific survival, time to recurrence, and time to distant recurrence with hazard ratios of 4.8 to 44.1. CONCLUSIONS: The p53-dependent molecular markers of angiogenesis are of limited utility in developing a clinical strategy for postoperative management of stage I ovarian carcinoma. Microvessel density impacts survival and metastasis for high-risk stage IC disease. Adjuvant chemotherapy is necessary, but not sufficient, for cure of high-risk stage I epithelial ovarian cancers.

Docetaxel and vinorelbine plus GM-CSF in malignant melanoma.

Patients having locoregional or metastatic melanoma have a poor prognosis, with 50% to 100% of patients dying from the disease within 5 years. Current chemotherapy regimens offer limited benefits to these patients, and more effective and less toxic treatments are needed. We therefore piloted a study of docetaxel (Taxotere), vinorelbine (Navelbine), granulocyte-macrophage colony-stimulating factor (GM-CSF, sargramostim [Leukine]), or the DVS regimen, in patients with stage IV melanoma. Eight patients were treated after previous biochemotherapy and two patients were given the regimen as an initial treatment. The DVS regimen consisted of docetaxel at 40 mg/m2 i.v. over 1 hour, vinorelbine at 30 mg/m2 i.v. over 6 to 10 minutes every 14 days, and GM-CSF at 250 mg/m2 SC on days 2 to 12. No grade 3 or 4 toxicities were encountered. Of the 10 patients evaluable for response, 5 were partial responders (50% response rate). Time to progression for the 10 cases ranged from 2 to 26+ months (median: 8 months). The DVS regimen was active against advanced melanoma in both previously treated and untreated patients. A larger study to confirm the activity of the DVS regimen for stage IV melanoma is currently under way.

Breast cancer chemoprevention phase I evaluation of biomarker modulation by arzoxifene, a third generation selective estrogen receptor modulator.

PURPOSE: Arzoxifene, a new selective estrogen receptor modulator with strong breast antiestrogen activity and absence of uterine agonist activity, was explored as a potential chemoprevention agent. We performed a multi-institutional evaluation of arzoxifene in women with newly diagnosed ductal carcinoma in situ or T1/T2 invasive cancer. EXPERIMENTAL DESIGN: In a Phase IA trial, 50 pre- or postmenopausal women were randomized to 10, 20, or 50 mg of arzoxifene daily in the interval between biopsy and re-excision or were enrolled as no-treatment controls. In a Phase IB trial, 76 postmenopausal women were randomized to 20 mg of arzoxifene versus matched placebo. Serum specimens collected at entry and at re-excision were assayed for various hormones and growth factors. Tissue from biopsies (estrogen receptor + and/or progesterone receptor +) and re-excision specimens was evaluated immunohistochemically for proliferation (Ki-67 by MIB-1 and proliferating cell nuclear antigen) and other biomarkers. RESULTS: In both trials, increases in serum sex hormone binding globulin were noted, as were decreases in insulin-like growth factor (IGF)-I and the IGF-I:IGF binding protein-3 ratio (P < 0.007 versus control/placebo). For 45 evaluable women in Phase IA, decreases in proliferation indices were more prevalent for arzoxifene (particularly 20 mg) than for controls. For 58 evaluable women in Phase IB, a decrease in estrogen receptor expression for arzoxifene was observed compared with no change with placebo (P = 0.0068). However, decreases in proliferation indices for arzoxifene were not statistically different from placebo, perhaps due to a confounding effect of stopping hormone replacement therapy before entry. CONCLUSION: Given the favorable side effect profile and the biomarker modulations reported here, arzoxifene remains a reasonable candidate for additional study as a breast cancer chemoprevention agent.

Assay-assisted treatment selection for women with breast or ovarian cancer.

Although women suffering from advanced cancer of the breast or ovary are unlikely to be cured, several active agents are available that can prolong their lives. The use of these agents is based on demonstrated benefit in large randomized clinical trials, and the clinical activity of these chemotherapy regimens is initially high, with 60%-70% of patients responding. Unfortunately, their benefit in the second-line setting is often limited, with less than 30% of patients showing significant disease response. Thus some 70% of patients may undergo ineffective treatment during the course of their disease, while still suffering from significant chemotherapy-related toxicity. Having some foreknowledge of a given agent's expected result before its administration would therefore benefit the individual patient. In vitro drug response testing, first developed to assist in the selection of antibiotics for patients with bacterial infections, has recently been demonstrated to accurately predict how cancer patients will respond to chemotherapy. This review discusses the historical development of in vitro testing for cancer patients, some of the pitfalls encountered, and offers an assessment of their current utility. Results of various clinical trials that evaluated correlations between in vitro tumor response and clinical outcomes are described. These data suggest that in vitro drug response assays can accurately predict drug resistance and can identify patients who are more or less likely to benefit from a given agent.

Measurement of volumetric and vascular changes with dynamic contrast enhanced MRI for cancer therapy monitoring.

Longitudinal dynamic contrast enhanced MRI studies were undertaken to monitor therapy induced volumetric and vascular changes. Three study components are presented in this work: one animal tumor chemotherapy study (R3230 AC adenocarcinoma treated with Taxotere), one patient with invasive lobular breast cancer undergoing neoadjuvant chemotherapy (AC regimen), and one patient with brain metastasis of primary breast cancer undergoing radiation therapy (40 Gray whole brain irradiation). In the animal study two contrast media with different molecular weights, Gadodiamide and Gadomer-17, were used. Only Gadomer-17 revealed significant changes in vascular properties. The responders showed decreased V(b) (vascular volume index) and K(2) (out-flux transport rate), which preceded tumor regression. The control tumors showed increased V(b) and K(2), before tumor growth became much faster. In the patient undergoing neoadjuvant therapy, the tumor was shrinking by 45% after 2 cycles of treatment, then again by 45% after 2 additional cycles. K(2) was decreasing over time with treatment. In the patient with brain metastasis, the 2 follow-up studies were much longer apart to monitor the regression and relapse of lesions. The pre-treatment volumes of lesions in the group without recurrence were significantly smaller compared to those with recurrence. In summary, the tumor volume was more sensitive than the vascular parameters measured by the small extracellular contrast medium for the assessment of therapy response and prediction of recurrence. The vascular properties measured by macromolecular contrast medium may have the potential to serve as early therapeutic efficacy indicators.

Pharmacokinetics of single-agent axitinib across multiple solid tumor types.

PURPOSE: Axitinib, a potent and selective inhibitor of vascular endothelial growth factor receptors, showed antitumor activity as a single agent against several solid tumor types in Phase II and III trials. This study was conducted to evaluate axitinib pharmacokinetics across a variety of solid tumors. METHODS: The current study analyzed the pharmacokinetics of axitinib in 110 patients with non-small cell lung cancer (NSCLC), thyroid cancer, or melanoma from three Phase II trials plus 127 healthy volunteers, using nonlinear mixed-effects modeling. Boxplots of maximum observed plasma concentration (C max) and area under the plasma concentration-time curve (AUC) of data from these tumor populations was compared to C max and AUC from the final population pharmacokinetic model developed for metastatic renal cell carcinoma (mRCC) to compare axitinib pharmacokinetics across different tumor types. RESULTS: Axitinib disposition based on data from 237 subjects was best described using a two-compartment model with first-order absorption and lag time. Population estimates for systemic clearance, central volume of distribution, absorption rate constant, absolute bioavailability, and lag time were 20.1 L/h, 56.2 L, 1.26/h(-1), 0.663, and 0.448 h, respectively. Statistically significant covariates included gender on clearance, and body weight on central volume of distribution. However, predicted changes due to gender and body weight were found not clinically meaningful. The final analysis indicated that the pharmacokinetic model for mRCC was able to successfully describe axitinib pharmacokinetics in patients with NSCLC, thyroid cancer, and melanoma. CONCLUSION: The pharmacokinetics of axitinib appears to be similar across a variety of tumor types.

A phase II study of gemcitabine and oxaliplatin in advanced transitional cell carcinoma of the bladder.

Cisplatin-based chemotherapy is recommended for use as first-line treatment for patients with advanced transitional cell carcinoma of the bladder. Unfortunately, 30-50 % of patients are ineligible for cisplatin due to renal insufficiency. Oxaliplatin is a less nephrotoxic platin which can be used for patients with impaired renal function. We carried out a phase II study of gemcitabine (1,200 mg/m²) in combination with oxaliplatin (100 mg/m²) given on days 1 and 14 every 28 days (GEMOX) in predominantly cisplatin-'unfit' stage IV transitional cell bladder cancer patients to determine whether this combination exhibited a clinical activity profile similar to cisplatin plus gemcitabine. Eighteen patients with a median GFR of 49 ml/min were enrolled. GEMOX treatment led to a 36 % response rate in assessable patients. Median progression-free survival was 4.9 months, with a median overall survival (OS) of 10.4 months and a one-year survival rate of 44.4 %. GEMOX in bladder cancer patients exhibited a tolerable side effects profile, with thrombocytopenia as the most frequent grade 3/4 toxicity. These findings suggest that GEMOX is an active combination in advanced bladder cancer patients with reduced renal function.

Thrombospondin-1 expression in melanoma is blocked by methylation and targeted reversal by 5-Aza-deoxycytidine suppresses angiogenesis.

BACKGROUND: Reversibility of aberrant methylation via pharmacological means is an attractive target for therapies through epigenetic reprogramming. To establish that pharmacologic reversal of methylation could result in functional inhibition of angiogenesis, we undertook in vitro and in vivo studies of thrombospondin-1 (TSP1), a known inhibitor of angiogenesis. TSP1 is methylated in several malignancies, and can inhibit angiogenesis in melanoma xenografts. We analyzed effects of 5-Aza-deoxycytidine (5-Aza-dC) on melanoma cells in vitro to confirm reversal of promoter hypermethylation and restoration of TSP1 expression. We then investigated the effects of TSP1 expression on new blood vessel formation and tumor growth in vivo. Finally, to determine potential for clinical translation, the methylation status of TSP1 promoter regions of nevi and melanoma tissues was investigated. RESULTS: 5-Aza-dC reduced DNA (cytosine-5)-methyltransferase 1 (DNMT1) protein, reversed promoter hypermethylation, and restored TSP1 expression in five melanoma cell lines, while having no effect on TSP1 protein levels in normal human melanocytes. In in vivo neovascularization studies, mice were implanted with melanoma cells (A375) either untreated or treated with 5Aza-dC. Vessels at tumor sites were counted by an observer blinded to treatments and the number of tumor vessels was significantly decreased at pretreated tumor sites. This difference occurred before a significant difference in tumor volumes was seen, yet in further studies the average tumor volume in mice treated in vivo with 5-Aza-dC was decreased by 55% compared to untreated controls. Knockdown of TSP1 expression with shRNA enhanced tumor-induced angiogenesis by 68%. Analyses of promoter methylation status of TSP1 in tumors derived from untreated and treated mice identified 67% of tumors from untreated and 17% of tumors from treated mice with partial methylation consistent with the methylation specific PCR analysis of A375 cells. Examination of methylation patterns in the promoter of TSP1 and comparison of aberrantly methylated TSP1 in melanoma with non-malignant nevi identified a significantly higher frequency of promoter methylation in tumor samples from melanoma patients. CONCLUSIONS: Pharmacological reversal of methylation silenced TSP1 had functional biological consequences in enhancing angiogenesis inhibition and inducing antitumor effects to decrease murine melanoma growth. Angiogenesis inhibition is an additional mechanism by which epigenetic modulators can have antitumor effects.