A phase 1 safety and bioimaging trial of antibody DS-8895a against EphA2 in patients with advanced or metastatic EphA2 positive cancers.

Ephrin type-A 2 (EphA2) is a transmembrane receptor expressed in epithelial cancers. We report on a phase I dose escalation and biodistribution study of DS-8895a, an anti-EphA2 antibody, in patients with advanced EphA2 positive cancers. DS-8895a was administered at 1, 3, 10 or 20 mg/kg every 2 weeks to determine safety, pharmacokinetics and anti-tumor efficacy. All patients underwent 89Zr trace-labelled infusion of DS-8895a (89Zr-DS-8995a) positron emission tomography imaging to determine the biodistribution of DS-8895a, and correlate findings with EphA2 expression, receptor saturation and response. Nine patients were enrolled on study. Of patients enrolled, seven patients received at least one infusion of DS-8895a: four patients received 1 mg/kg dose (Cohort 1) and three patients received 3 mg/kg dose (Cohort 2). Median age was 67.0 years (range 52-81), majority male (71%), and median number of prior systemic therapies was three (range 0-8). The primary cancer diagnosis was colorectal cancer (two patients) and one patient each had gastric, head and neck, high-grade serous adenocarcinoma, lung, and pancreatic cancers. No dose-limiting toxicities or treatment-related adverse events reported. The best response for the patients in Cohort 1 was stable disease and in Cohort 2 was progressive disease. 89Zr-DS-8895a demonstrated no normal tissue uptake and specific low-grade uptake in most tumours. DS-8895a had limited therapeutic efficacy at doses evaluated and 89Zr-DS-8895a demonstrated low tumour uptake. The biodistribution data from this study were key in halting further development of DS-8895a, highlighting the importance of biodistribution studies in drug development. (Trial registration: ClinicalTrials.gov Identifier NCT02252211).

Phase II study of everolimus (RAD001) monotherapy as first-line treatment in advanced biliary tract cancer with biomarker exploration: the RADiChol Study.

BACKGROUND: Advanced biliary tract cancers (BTCs) have a poor prognosis and limited treatment options. This exploratory phase II study aimed to evaluate the activity of the mTOR inhibitor everolimus in advanced BTC and explore prognostic biomarkers. METHODS: Patients with advanced BTCs, who had not received chemotherapy for advanced disease, were enroled to receive everolimus (10 mg daily). The primary endpoint was disease control rate (DCR) at 12 weeks. Secondary endpoints included overall response rate, progression-free survival (PFS), overall survival (OS) and adverse events. Activation status of the RAS and phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathways was assessed by DNA sequencing and immunohistochemistry on archival tumour tissue. RESULTS: The study enroled 27 patients and the DCR at 12 weeks was 48%. Median PFS was 5.5 months (95% confidence interval (CI): 2.1-10.0 months) and median OS was 9.5 months (95% CI: 5.5-16.6 months). DCR at 12 weeks was significantly worse for gall bladder carcinoma compared to other anatomical sites, and there was a trend towards a worsened PFS and OS. Treatment was well tolerated. KRAS (12%) and PIK3CA mutations (12%) were uncommon. Immunohistochemical staining for PI3K/AKT/mTOR pathways did not significantly correlate with outcome. CONCLUSION: In unselected patients, everolimus demonstrated clinical activity as first-line monotherapy in advanced BTC.

Digital PCR of Genomic Rearrangements for Monitoring Circulating Tumour DNA.

Identifying circulating tumour DNA (ctDNA) for monitoring of cancer therapy is dependent on the development of readily designed, sensitive cancer-specific DNA markers. Genomic rearrangements that are present in the vast majority of cancers provide such markers.Tumour DNA isolated from two fresh-frozen lung tumours underwent whole genome sequencing. Genomic rearrangements were detected using a new computational algorithm, GRIDSS. Four genomic rearrangements from each tumour were chosen for further study using rearrangement-specific primers. Six of the eight rearrangements tested were identified as tumour-specific, the remaining two were present in the germline. ctDNA was quantified using digital PCR for the tumour genomic rearrangements in patient blood. Interestingly, one of the patients had no detectable ctDNA either prior to or post surgery although the rearrangements were readily detectable in the tumour DNA.This study demonstrates the feasibility of using digital PCR based on genomic rearrangements for the monitoring of minimal residual disease. In addition, whole genome sequencing provided further information enabling therapeutic choices including the identification of a cryptic EGFR exon 19 deletion in one patient and the identification of a high somatic mutation load in the other patient. This approach can be used as a model for all cancers with rearranged genomes.

Global protein profiling reveals anti-EGFR monoclonal antibody 806-modulated proteins in A431 tumor xenografts.

An important mediator of tumorigenesis, the epidermal growth factor receptor (EGFR) is expressed in almost all non-transformed cell types, associated with tumor progression, angiogenesis and metastasis. The significance of the EGFR as a cancer therapeutic target is underscored by the clinical development of several different classes of EGFR antagonists, including monoclonal antibodies (mAb) and tyrosine kinase inhibitors. Extensive preclinical studies have demonstrated the anti-tumor effects of mAb806 against tumor xenografts overexpressing EGFR. EGF stimulation of A431 cells induces rapid tyrosine phosphorylation of intracellular signalling proteins which regulate cell proliferation and apoptosis. Detailed understanding of the intracellular signalling pathways and components modulated by mAbs (such as mAb806) to EGFR, and other growth factor receptors, remain limited. The use of fluorescence 2D difference gel electrophoresis (2D DIGE), coupled with sensitive MS-based protein profiling in A431 tumor (epidermoid carcinoma) xenografts, in combination with mAb806, revealed proteins modulating endocytosis, cell architecture, apoptosis, cell signalling pathways and cell cycle regulation, including Dynamin-1-like protein, cofilin-1 protein, and 14-3-3 protein zeta/delta. Further, we report various proteins, including Interferon-induced protein 53 (IFI53), and Oncogene EMS1 (EMS1) which have roles in the tumor microenvironment, regulating cancer cell invasiveness, angiogenesis and formation of metastases. These findings contribute to understanding the underlying biological processes associated with mAb806 therapy of EGFR-positive tumors, and identifying further potential protein markers that may contribute in assessment of the treatment response.

Villin expression is frequently lost in poorly differentiated colon cancer.

Colorectal cancers (CRCs) are classified as having microsatellite instability (MSI) or chromosomal instability (CIN); herein termed microsatellite stable (MSS). MSI colon cancers frequently display a poorly differentiated histology for which the molecular basis is not well understood. Gene expression and immunohistochemical profiling of MSS and MSI CRC cell lines and tumors revealed significant down-regulation of the intestinal-specific cytoskeletal protein villin in MSI colon cancer, with complete absence in 62% and 17% of MSI cell lines and tumors, respectively. Investigation of 577 CRCs linked loss of villin expression to poorly differentiated histology in MSI and MSS tumors. Furthermore, mislocalization of villin from the membrane was prognostic for poorer outcome in MSS patients. Loss of villin expression was not due to coding sequence mutations, epigenetic inactivation, or promoter mutation. Conversely, in transient transfection assays villin promoter activity reflected endogenous villin expression, suggesting transcriptional control. A screen of gut-specific transcription factors revealed a significant correlation between expression of villin and the homeobox transcription factor Cdx-1. Cdx-1 overexpression induced villin promoter activity, Cdx-1 knockdown down-regulated endogenous villin expression, and deletion of a key Cdx-binding site within the villin promoter attenuated promoter activity. Loss of Cdx-1 expression in CRC lines was associated with Cdx-1 promoter methylation. These findings demonstrate that loss of villin expression due to Cdx-1 loss is a feature of poorly differentiated CRCs.

Sox9 drives columnar differentiation of esophageal squamous epithelium: a possible role in the pathogenesis of Barrett's esophagus.

The molecular mechanism underlying the development of Barrett's esophagus (BE), the precursor to esophageal adenocarcinoma, remains unknown. Our previous work implicated sonic hedgehog (Shh) signaling as a possible driver of BE and suggested that bone morphogenetic protein 4 (Bmp4) and Sox9 were downstream mediators. We have utilized a novel in vivo tissue reconstitution model to investigate the relative roles of Bmp4 and Sox9 in driving metaplasia. Epithelia reconstituted from squamous epithelial cells or empty vector-transduced cells had a stratified squamous phenotype, reminiscent of normal esophagus. Expression of Bmp4 in the stromal compartment activated signaling in the epithelium but did not alter the squamous phenotype. In contrast, expression of Sox9 in squamous epithelial cells induced formation of columnar-like epithelium with expression of the columnar differentiation marker cytokeratin 8 and the intestinal-specific glycoprotein A33. In patient tissue, A33 protein was expressed specifically in BE, but not in normal esophagus. Expression of Cdx2, another putative driver of BE, alone had no effect on reconstitution of a squamous epithelium. Furthermore, epithelium coexpressing Cdx2 and Sox9 had a phenotype similar to epithelium expressing Sox9 alone. Our results demonstrate that Sox9 is sufficient to drive columnar differentiation of squamous epithelium and expression of an intestinal differentiation marker, reminiscent of BE. These data suggest that Shh-mediated expression of Sox9 may be an important early event in the development of BE and that the potential for inhibitors of the hedgehog pathway to be used in the treatment of BE and/or esophageal adenocarcinoma could be tested in the near future.

Paracrine IL-6 Signaling Confers Proliferation between Heterogeneous Inflammatory Breast Cancer Sub-Clones.

Inflammatory breast cancer (IBC) describes a highly aggressive form of breast cancer of diverse molecular subtypes and clonal heterogeneity across individual tumors. Accordingly, IBC is recognized by its clinical signs of inflammation, associated with expression of interleukin (IL)-6 and other inflammatory cytokines. Here, we investigate whether sub-clonal differences between expression of components of the IL-6 signaling cascade reveal a novel role for IL-6 to mediate a proliferative response in trans using two prototypical IBC cell lines. We find that SUM149 and SUM 190 cells faithfully replicate differential expression observed in a subset of human IBC specimens between IL-6, the activated form of the key downstream transcription factor STAT3, and of the HER2 receptor. Surprisingly, the high level of IL-6 produced by SUM149 cells activates STAT3 and stimulates proliferation in SUM190 cells, but not in SUM149 cells with low IL-6R expression. Importantly, SUM149 conditioned medium or co-culture with SUM149 cells induced growth of SUM190 cells, and this effect was abrogated by the IL-6R neutralizing antibody Tocilizumab. The results suggest a novel function for inter-clonal IL-6 signaling in IBC, whereby IL-6 promotes in trans proliferation of IL-6R and HER2-expressing responsive sub-clones and, therefore, may provide a vulnerability that can be exploited therapeutically by repurposing of a clinically approved antibody.

Expression of EGFR and conformational forms of EGFR in malignant pleural mesothelioma and its impact on survival.

AIM: Conformational forms of the epidermal growth factor receptor (EGFR) are pro-tumorigenic. The prevalence and impact of conformational forms of EGFR in malignant mesothelioma (MM) is unknown. We investigated expression of EGFR and conformational forms of EGFR by immunohistochemistry using EGFR-targeting monoclonal antibodies (mAb). In addition, EGFR gene amplification was investigated by fluorescent in-situ hybridization (FISH). Findings were correlated with survival. METHODS: Patients treated between 1988 and 2014 were identified from the thoracic surgery database of the Austin Hospital, Melbourne, Australia. Tissue microarrays (TMAs) were constructed, subjected to wild type (wt) EGFR IHC staining and FISH analysis. Conformational and mutation forms of EGFR were detected by IHC using mAb806, and LMH-151 which detects EGFRVIII. `H-scores` were derived and EGFR expression correlated with survival by Kaplan-Meier and log rank analysis. RESULTS: WtEGFR expression was seen in 93 % (299/321) of cases with overexpression (defined as an H-score ≥200) seen in more than half of cases (64 %). EGFR overexpression in MM was seen more commonly in the epithelioid subtype. EGFR overexpression was not associated with true EGFR amplification, although multiple copies were appreciated in samples with polysomy. EGFR expression did not correlate with survival. A conformational form of EGFR associated with EGFR dysregulation was found in 8.2 % of cases, and patients with these tumors had a trend towards a poorer outcome. No cases of the EGFRVIII mutation were identified. CONCLUSION: MM consistently demonstrated high expression of EGFR, with a subset of tumors showing conformational EGFR forms consistent with EGFR dysregulation, but withoutEGFR amplification or EGFR VIII mutation. wtEGFR expression did not influence survival. The impact of EGFR conformation on survival warrants further investigation.

Analysis of angiogenic and stromal biomarkers in a large malignant mesothelioma cohort.

BACKGROUND: Malignant mesothelioma (MM) is an aggressive malignancy of the pleura and other mesothelial membranes. Agents targeting vascular endothelial growth factor (VEGF) such as bevacizumab; and multi-kinase inhibitors such as nintedanib [angiokinase inhibitor of VEGF, platelet-derived growth factor (PDGF) receptor and fibroblast growth factor receptor (FGFR)] have recently demonstrated efficacy in MM. METHODS: Tissue microarrays (TMAs) were created from formalin-fixed, paraffin-embedded tissue samples obtained from 326 patients with MM who were treated surgically. PDGF-CC, FGFR-1, VEGF and CD31 expression were analysed by immunohistochemical (IHC) staining. The H-score method assigned a score of 0-300 to each sample, based on the percentage of cells stained at different intensities. CD31 was evaluated via Chalkley's method to evaluate microvessel density. We evaluated the association between expression of the biomarkers, clinicopathological factors and outcomes, in patients with MM. RESULTS: CD31 high (≥5) was seen in only 31/302 (10.3%) irrespective of histology. PDGF-CC high (≥150) was seen in 203 /310 (65%) of all samples. VEGF high (≥80) was seen in 219/322 (68%) of all MM with 143/209 (68%) of epithelioid histology. FGFR-1 high (≥40) was seen in 127/310 (41%) of all MM. There was no association of VEGF and FGFR-1 IHC with survival nor differences between histological subtypes. There was a non-significant trend towards poorer survival in epithelioid tumours with increased PDGF-CC expression (OS 18.5 vs 13.2 months; HR 0.7928; 95% CI 0.5958 to 1.055, P = 0.1110). High CD31 score was associated with significantly poorer survival (OS 12 vs 8.6 months; HR 0.48; 95% CI 0.2873 to 0.7941, P = 0.0044). Of the 31 patients with high CD31 scores; 23/31 (74%) were also high for PDGF-CC and 20/31 (64%) with high VEGF scores. CD31 was found to be an independent prognostic factor in multivariate analysis (HR 1.540; 95% CI 1.018 to 2.330; p = 0.041). CONCLUSIONS: High CD31 was an independent poor prognostic factor and high PDGF-CC expression was associated with poor survival in MM. Abrogating these pathways may have prognostic implications.

Mesenchyme to epithelial transition protein expression, gene copy number and clinical outcome in a large non-small cell lung cancer surgical cohort.

BACKGROUND: In non-small cell lung cancer (NSCLC), mesenchyme to epithelial transition (MET) protein abundance increases with disease stage and is implicated in resistance to tyrosine kinase inhibitors. To better clarify the impact of MET overexpression on tumor behavior, we investigated a large cohort of patients who underwent curative surgical resection to determine whether MET gene amplification or protein abundance was prognostic. METHODS: Tissue microarrays (TMAs) were constructed using triplicate 1 mm cores of FFPE primary NSCLC specimens. TMAs underwent immunohistochemical (IHC) staining with the SP44 clone (Ventana) and cores were considered positive if >50% of tumor exhibited 2+ staining. The highest of triplicate values was used. MET gene amplification was detected using either SISH using Ventana's MET DNP probe or FISH using the D7S486/CEP 7 Abbott Probe. DNA was subjected to mutational profiling using Sequenom's LungCarta panel. RESULTS: Data from two institutions comprising 763 patients (516; 68%) male were generated, including 360 stage I, 226 stage II, 160 stage III and 18 resected stage IV. High MET protein expression was detected in 25% (193/763), and was significantly more common in adenocarcinomas than squamous cell carcinoma (P<0.01). MET gene copy number (GCN) correlated with high MET protein expression by IHC (P=0.01). Increased MET protein expression was associated with EGFR and KRAS mutations (P<0.01 for both). Once polysomy was excluded, true MET gene amplification was detected in only 8/763 (1%) of samples. In multivariate analysis, neither MET protein abundance nor GCN were correlated to overall patient survival. CONCLUSIONS: MET expression by IHC and GCN amplification was not prognostic in this large Caucasian surgical series. MET's primary role remains as a therapeutic target.

A phase I biodistribution and pharmacokinetic trial of humanized monoclonal antibody Hu3s193 in patients with advanced epithelial cancers that express the Lewis-Y antigen.

PURPOSE: We report a first-in-man trial of a humanized antibody (hu3S193) against the Le(y) antigen. EXPERIMENTAL DESIGN: Patients with advanced Le(y)-positive cancers received four infusions of hu3S193 at weekly intervals, with four dose levels (5, 10, 20, and 40 mg/m(2)). The first infusion of hu3S193 was trace labeled with Indium-111, and biodistribution, pharmacokinetics, tumor uptake, and immune response were evaluated in all patients. RESULTS: A total of 15 patients (7 male/8 female; age range, 42-76 years; 6 breast, 8 colorectal cancer, and 1 non-small-cell lung cancer) were entered into the study. Transient grade 1 to 2 nausea and vomiting was observed following infusion of hu3S193 at the 40 mg/m(2) dose level only. There was one episode of dose-limiting toxicity with self-limiting Common Toxicity Criteria grade 3 elevated alkaline phosphatase observed in one patient with extensive liver metastases. The biodistribution of (111)In-hu3S193 showed no evidence of any consistent normal tissue uptake, and (111)In-hu3S193 uptake was observed in cutaneous, lymph node, and hepatic metastases. Hu3S193 displayed a long serum half-life (T(1/2)beta = 189.63 +/- 62.17 h). Clinical responses consisted of 4 patients with stable disease and 11 patients with progressive disease, although one patient experienced a 89% decrease in a lymph node mass, and one patient experienced inflammatory symptoms in cutaneous metastases, suggestive of a biological effect of hu3S193. No immune responses (human anti-human antibody) to hu3S193 were observed. CONCLUSION: Hu3S193 is well tolerated and selectively targets tumors, and the long half-life and biological function in vivo of this antibody makes it an attractive potential therapy for patients with Le(y)-expressing cancers.

Metabolic response evaluation for colorectal liver metastases and correlation to pathologic response and tumour markers.

BACKGROUND: Tumour metabolic response to chemotherapy is increasingly recognized as a prognostic indicator for colorectal cancer liver metastases (CRCLM). However, its clinical role and the underlying biological mechanism of its prognostic ability are unclear. This study compares metabolic to pathologic response for CRCLM, and correlates metabolic response to tumour expression of six key biomarkers. METHODS: Thirty-seven patients who had positron emission tomography imaging before and after pre-operative chemotherapy prior to liver resection for CRCLM were included. Metabolic response was assessed according to the positron emission tomography response criteria in solid tumours (PERCIST) and correlated to recurrence-free and overall survival. PERCIST was compared to tumour regression grading, computed tomography (CT) response, tumour necrosis and mucin and immunohistochemical expression of Ki-67, hypoxia inducible factor 1α, vascular endothelial growth factor, p53, p16 and vimentin. Area under the receiver operating characteristic curve (AUC), Kaplan-Meier survival, Spearman's correlation (rs ) and multivariate Cox regression analyses were used. RESULTS: PERCIST correlated significantly to 2-year mortality (AUC = 0.162, P < 0.01) and 2-year recurrence (AUC = 0.284, P = 0.03). Metabolically responsive tumours conferred a better overall survival (P = 0.01) and recurrence-free survival (P = 0.03). Tumour regression grading did not stratify for outcome. Metabolic response was significantly correlated to Ki-67 and p16 expression (rs = 0.559 and rs = -0.549, respectively). Multivariate analysis revealed only PERCIST to be correlated to death and recurrence. CONCLUSION: Pre-operative PERCIST assessment of CRCLM was more prognostic than pathologic and CT response assessment. Metabolic non-response correlated with tumour proliferation and loss of tumour suppression.

Development of monoclonal anti-PDGF-CC antibodies as tools for investigating human tissue expression and for blocking PDGF-CC induced PDGFRα signalling in vivo.

PDGF-CC is a member of the platelet-derived growth factor (PDGF) family that stimulates PDGFRα phosphorylation and thereby activates intracellular signalling events essential for development but also in cancer, fibrosis and neuropathologies involving blood-brain barrier (BBB) disruption. In order to elucidate the biological and pathological role(s) of PDGF-CC signalling, we have generated high affinity neutralizing monoclonal antibodies (mAbs) recognizing human PDGF-CC. We determined the complementarity determining regions (CDRs) of the selected clones, and mapped the binding epitope for clone 6B3. Using the monoclonal 6B3, we determined the expression pattern for PDGF-CC in different human primary tumours and control tissues, and explored its ability to neutralize PDGF-CC-induced phosphorylation of PDGFRα. In addition, we showed that PDGF-CC induced disruption of the blood-retinal barrier (BRB) was significantly reduced upon intraperitoneal administration of a chimeric anti-PDGF-CC antibody. In summary, we report on high affinity monoclonal antibodies against PDGF-CC that have therapeutic efficacy in vivo.

DUSP5 is methylated in CIMP-high colorectal cancer but is not a major regulator of intestinal cell proliferation and tumorigenesis.

The ERK signalling pathway regulates key cell fate decisions in the intestinal epithelium and is frequently dysregulated in colorectal cancers (CRCs). Variations in the dynamics of ERK activation can induce different biological outcomes and are regulated by multiple mechanisms, including activation of negative feedback loops involving transcriptional induction of dual-specificity phosphatases (DUSPs). We have found that the nuclear ERK-selective phosphatase DUSP5 is downregulated in colorectal tumours and cell lines, as previously observed in gastric and prostate cancer. The DUSP5 promoter is methylated in a subset of CRC cell lines and primary tumours, particularly those with a CpG island methylator phenotype (CIMP). However, this epigenetic change alone could not account for reduced DUSP5 expression in CRC cells. Functionally, DUSP5 depletion failed to alter ERK signalling or proliferation in CRC cell lines, and its transgenic overexpression in the mouse intestine had minimal impact on normal intestinal homeostasis or tumour development. Our results suggest that DUSP5 plays a limited role in regulating ERK signalling associated with the growth of colorectal tumours, but that methylation the DUSP5 gene promoter can serve as an additional means of identifying CIMP-high colorectal cancers.

The Immune Microenvironment, Genome-wide Copy Number Aberrations, and Survival in Mesothelioma.

INTRODUCTION: Results of recent clinical studies of immune checkpoint inhibitors in malignant pleural mesothelioma (MPM) have dampened initial enthusiasm. However, the immune environment and targets of these treatments such as programmed cell death protein 1 and its ligand programmed death ligand 1 (PD-L1) have not been well characterized in MPM. Using a large cohort of patients, we investigated PD-L1 expression, immune infiltrates, and genome-wide copy number status and correlated them to clinicopathological features. METHODS: Tissue microarrays were constructed and stained with PD-L1(clone E1L3N [Cell Signaling Technology, Danvers, MA]), cluster of differentiation 4, cluster of differentiation 8, and forkhead box P3 antibodies. PD-L1 positivity was defined as at least 5% membranous staining regardless of intensity, and high PD-L1 positivity was defined as at least 50%. Genomic DNA from a representative subset of 113 patients was used for genome-wide copy number analysis. The percent genome alteration was computed as a proxy for genomic instability, and statistical analyses were used to relate copy number aberrations to other variables. RESULTS: Among 329 patients evaluated, PD-L1 positivity was detected in 130 of 311 (41.7%), but high PD-L1 positivity was seen in only 30 of 311 (9.6%). PD-L1 positivity correlated with nonepithelioid histological subtype and increased infiltration with cluster of differentiation 4-positive, cluster of differentiation 8-positive, and forkhead box P3-positive lymphocytes. High PD-L1-positive expression correlated with worse prognosis (hazard ratio = 2.37, 95% confidence interval: 1.57-3.56, p < 0.001) in univariate analysis but not in multivariate analysis. Higher percent genome alteration was associated with epithelioid histological subtype and poorer survival (hazard ratio = 1.59, 95% confidence interval: 1.01-2.5, p = 0.04) but not PD-L1 expression. CONCLUSIONS: PD-L1 expression was associated with nonepithelioid MPM, poor clinical outcome, and increased immunological infiltrates. Increased genomic instability did not correlate with PD-L1 expression but was associated with poorer survival.

Correlation of hypoxic cell fraction and angiogenesis with glucose metabolic rate in gliomas using 18F-fluoromisonidazole, 18F-FDG PET, and immunohistochemical studies.

UNLABELLED: PET offers a noninvasive means to assess neoplasms, in view of its sensitivity and accuracy in staging tumors and potentially in monitoring treatment response. The aim of this study was to evaluate newly diagnosed primary brain tumors for the presence of hypoxia, as indicated by the uptake of 18F-fluoromisonidazole (18F-FMISO) and to examine the relationship of hypoxia to the uptake of 18F-FDG and molecular markers of hypoxia. METHODS: Seventeen patients with suspected primary glioma were enrolled prospectively in this study. Sixteen patients had histology, with 2 having metastatic disease. All patients had PET studies with 18F-FMISO and 18F-FDG and MRI studies. Immunohistochemistry was undertaken with tumor markers of angiogenesis and hypoxia. Patients were monitored for disease progression and statistical analysis of data was performed. RESULTS: Of the 14 patients with histology, 8 died with a median time of 16 mo (range, 2-30 mo) until death. Of those who died, 7 had positive and 1 had negative 18F-FMISO uptake. 18F-FMISO uptake was observed in all high-grade gliomas but not in low-grade gliomas. A significant relationship was found between 18F-FDG or 18F-FMISO uptake and expression of VEGF-R1 and Ki67 expression. Other immunohistochemical markers demonstrated a trend toward increased uptake but none was significant. CONCLUSION: 18F-FMISO PET provides a noninvasive assessment of hypoxia in glioma and was prognostic for treatment outcomes in the majority of patients. 18F-FMISO PET may have a role not only in directing patients toward targeted hypoxic therapies but also in monitoring response to such therapies.

Lack of correlation of hypoxic cell fraction and angiogenesis with glucose metabolic rate in non-small cell lung cancer assessed by 18F-Fluoromisonidazole and 18F-FDG PET.

UNLABELLED: PET offers a noninvasive means to assess neoplasms, in view of its sensitivity and accuracy in staging tumors and potentially in monitoring treatment response. The aim of this study was to evaluate newly diagnosed non-small cell lung cancer (NSCLC) for the presence of hypoxia, as indicated by the uptake of (18)F-Fluoromisonidazole ((18)F-FMISO), and to examine the relationship of hypoxia to the uptake of (18)F-FDG, microvessel density, and other molecular markers of hypoxia. METHODS: Twenty-one patients with suspected or biopsy-proven NSCLC were enrolled prospectively in this study. All patients had PET studies with (18)F-FMISO and (18)F-FDG. Seventeen patients subsequently underwent surgery, with analysis performed for tumor markers of angiogenesis and hypoxia. RESULTS: In the 17 patients with resectable NSCLC (13 men, 4 women; age range, 51-77 y), the mean (18)F-FMISO uptake in tumor was significantly lower than that of (18)F-FDG uptake (P < 0.0001) and showed no correlation with (18)F-FDG uptake (r = 0.26). The mean (95% confidence interval [CI]) (18)F-FMISO SUV(max) (maximum standardized uptake value) was 1.20 [0.95-1.45] compared with the mean [95% CI] (18)F-FDG SUV(max) of 5.99 [4.62-7.35]. The correlation between (18)F-FMISO uptake, (18)F-FDG uptake, and tumor markers of hypoxia and angiogenesis was poor. A weakly positive correlation between (18)F-FMISO and (18)F-FDG uptake and Ki67 was found. CONCLUSION: The hypoxic cell fraction of primary NSCLC is consistently low, and there is no significant correlation in NSCLC between hypoxia and glucose metabolism in NSCLC assessed by (18)F-FDG. These findings have direct implications in understanding the role of angiogenesis and hypoxia in NSCLC biology.

Treatment of human tumor xenografts with monoclonal antibody 806 in combination with a prototypical epidermal growth factor receptor-specific antibody generates enhanced antitumor activity.

Monoclonal antibody (mAb) 806 is a novel epidermal growth factor receptor (EGFR) antibody with significant antitumor activity that recognizes a mutant EGFR commonly expressed in glioma known as delta2-7 EGFR (de2-7 EGFR or EGFRvIII) and a subset of the wild-type (wt) EGFR found in cells that overexpress the receptor. We have used two human xenograft mouse models to examine the efficacy of mAb 806 in combination with mAb 528, a prototypical anti-EGFR antibody with similar specificity to cetuximab. Treatment of nude mice, bearing s.c. or i.c. tumor human xenografts expressing the wt or de2-7 EGFR, with mAbs 806 and 528 in combination resulted in additive and in some cases synergistic, antitumor activity. Interestingly, mAb 528 was also effective against xenografts expressing the ligand independent de2-7 EGFR when used as a single agent, showing that its antitumor activity is not merely mediated through inhibition of ligand binding. When used as single agents, neither mAbs 806 or 528 induced down-regulation of the de2-7 EGFR either in vitro or in vivo. In contrast, the combination of antibodies produced a rapid and dramatic decrease in the total cell surface de2-7 EGFR both in vitro and in xenografts. Consistent with this decrease in total cell surface de2-7 EGFR, we observed up-regulation of the cell cycle inhibitor p27(KIP1) and a decrease in tumor cell proliferation as measured by Ki-67 immunostaining when the antibodies were used in combination in vivo. Thus, mAb 806 can synergize with other EGFR-specific antibodies thereby providing a rationale for its translation into the clinic.

A phase I trial of humanized monoclonal antibody A33 in patients with colorectal carcinoma: biodistribution, pharmacokinetics, and quantitative tumor uptake.

PURPOSE: To determine the in vivo characteristics of huA33, a CDR-grafted humanized antibody against the A33 antigen, we have conducted an open-label, dose escalation, biopsy-based phase I trial of huA33 in patients with colorectal carcinoma. EXPERIMENTAL DESIGN: Patients with colorectal carcinoma were infused with [131I]huA33 (400 MBq: 10 mCi) and [125I]huA33 (40 MBq: 1 mCi) 1 week before surgery. There were four huA33 dose levels (0.25, 1.0, 5.0, and 10 mg/m2). Adverse events, pharmacokinetics, biodistribution, tumor biopsies, and immune responses to huA33 were evaluated. RESULTS: There were 12 patients entered into the trial (6 males and 6 females; age range, 39-66 years). No dose-limiting toxicity was observed. The biodistribution of huA33 showed excellent uptake of [131I]huA33 in metastatic colorectal carcinoma. Pharmacokinetic analysis showed no significant difference in terminal half-life (T1/2beta) between dose levels (mean +/- SD, 86.92 +/- 22.12 hours). Modeling of colon uptake of huA33 showed a T1/2 of elimination of 32.4 +/- 8.1 hours. Quantitative tumor uptake ranged from 2.1 x 10(-3) to 11.1 x 10(-3) %ID/g, and tumor/normal tissue and tumor/serum ratios reached as high as 16.3:1 and 4.5:1, respectively. Biosensor analysis detected low-level human anti-human antibody responses in four patients following huA33 infusion. CONCLUSIONS: huA33 shows selective and rapid localization to colorectal carcinoma in vivo and penetrates to the center of large necrotic tumors, and colon elimination half-life of huA33 is equivalent to basal colonocyte turnover. The excellent targeting characteristics of this humanized antibody indicate potential for the targeted therapy of metastatic colorectal cancer in future trials.