Elevated IL-33 expression is associated with pediatric eosinophilic esophagitis, and exogenous IL-33 promotes eosinophilic esophagitis development in mice.

We tested whether the T helper (Th) type 2 (Th2) cell agonist and allergenic ligand IL-33 was associated with eosinophilic esophagitis (EoE) development in a pediatric cohort and whether IL-33 protein could induce disease symptoms in mice. Biopsies from EoE patients or controls were used to measure IL-33 mRNA and protein expression. Increased expression of IL-33 mRNA was found in the esophageal mucosa in EoE. IL-33 protein was detected in cells negative for CD45, mast cells, and epithelial cell markers near blood vessels. Circulating levels of IL-33 were not increased. The time course for IL-33 gene expression was quantified in an established Aspergillus fumigatus allergen mouse model of EoE. Because IL-33 induction was transient in this model and chronicity of IL-33 expression has been demonstrated in humans, naive mice were treated with recombinant IL-33 for 1 wk and esophageal pathology was evaluated. IL-33 application produced changes consistent with phenotypically early EoE, including transmural eosinophilia, mucosal hyperproliferation, and upregulation of eosinophilic genes and chemokines. Th2 cytokines, including IL-13, along with innate lymphoid cell group 2, Th1/17, and M2 macrophage marker genes, were increased after IL-33 application. IL-33-induced eosinophilia was ablated in IL-13 null mice. In addition, IL-33 induced a profound inhibition of the regulatory T cell gene signature. We conclude that IL-33 gene expression is associated with pediatric EoE development and that application of recombinant protein in mice phenocopies the early clinical phase of the human disease in an IL-13-dependent manner. IL-33 inhibition of esophageal regulatory T cell function may induce loss of antigenic tolerance, thereby providing a mechanistic rationale for EoE development.

Highly prevalent colorectal cancer-infiltrating LAP⁺ Foxp3⁻ T cells exhibit more potent immunosuppressive activity than Foxp3⁺ regulatory T cells.

Although elevated CD4⁺Foxp3⁺ regulatory T cell (Treg) frequencies within tumors are well documented, the functional and phenotypic characteristics of CD4⁺Foxp3⁺ and CD4⁺Foxp3⁻ T cell subsets from matched blood, healthy colon, and colorectal cancer require in-depth investigation. Flow cytometry revealed that the majority of intratumoral CD4⁺Foxp3⁺ T cells (Tregs) were Helios⁺ and expressed higher levels of cytotoxic T-lymphocyte antigen 4 (CTLA-4) and CD39 than Tregs from colon and blood. Moreover, ∼30% of intratumoral CD4⁺Foxp3⁻ T cells expressed markers associated with regulatory functions, including latency-associated peptide (LAP), lymphocyte activation gene-3 (LAG-3), and CD25. This unique population of cells produced interleukin-10 (IL-10) and transforming growth factor-ß (TGF-ß), and was ∼50-fold more suppressive than Foxp3⁺ Tregs. Thus, intratumoral Tregs are diverse, posing multiple obstacles to immunotherapeutic intervention in colorectal malignancies.

Cytokine and angiogenic factors associated with efficacy and toxicity of pazopanib in advanced soft-tissue sarcoma: an EORTC-STBSG study.

BACKGROUND: Pazopanib has activity in relapsed non-adipocytic soft-tissue sarcomas (STS). A series of serum cytokines and angiogenic factors (CAFs) at baseline and changes in soluble vascular endothelial growth factor receptor-2 (sVEGFR2) or placental-derived growth factor (PlGF) levels during treatment were explored for their association with outcome. METHODS: Twenty-three baseline CAFs, and sVEGFR2 and PlGF changes were measured in 85 and 32 patients, respectively. Associations between baseline CAF levels and efficacy parameters, plus between-week 12 sVEGFR2 and PlGF levels and pazopanib-specific toxicities were investigated. RESULTS: At baseline, low interleukin (IL)-12 p40 subunit and MPC3 levels were associated with better progression-free survival (PFS) at 12 weeks (PFS(12wks)), low basic nerve growth factor and hepatocyte growth factor with a better PFS, and low inter-cellular adhesion molecule-1 and IL-2 receptor alpha with prolonged overall survival (OS; all P<0.05). Pazopanib decreased sVEGFR2 and increased PlGF levels. Low sVEGFR2 and high PlGF levels at week 12 were associated with higher-grade hypertension, with TSH elevations and with poorer PFS(12wks), and OS (both P<0.05). CONCLUSION: Several baseline CAFs were related to outcome parameters. Low sVEGFR2 and high PlGF at week 12 associate with several pazopanib-specific toxicities and poorer efficacy. If confirmed, these factors may be used as early markers for response to and toxicity from pazopanib, enabling further individualisation of STS treatment.

A Phase I study of the angiogenesis inhibitor SU5416 (semaxanib) in solid tumours, incorporating dynamic contrast MR pharmacodynamic end points.

SU5416 (Z-3-[(2,4-dimethylpyrrol-5-yl)methylidenyl]-2-indolinone; semaxanib) is a small molecule inhibitor of the vascular endothelial growth factor receptor (VEGFR2). A Phase I dose escalation study was performed. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was used as a pharmacodynamic assessment tool. In all, 27 patients were recruited. SU5416 was administered twice weekly by fixed rate intravenous infusion. Patients were treated in sequential cohorts of three patients at 48, 65, 85 110 and 145 mg m-2. A further dose level of 190 mg m-2 after a 2-week lead in period at a lower dose was completed; thereafter, the cohort at 145 mg m-2 was expanded. SU5416 showed linear pharmacokinetics to 145 mg m-2 with a large volume of distribution and rapid clearance. A significant degree of interpatient variability was seen. SU5416 was well tolerated, by definition a maximum-tolerated dose was not defined. No reproducible changes were seen in DCE-MRI end points. Serial assessments of VEGF in a cohort of patients treated at 145 mg m-2 did not show a statistically significant treatment-related change. Parallel assessments of the impact of SU5416 on coagulation profiles in six patients showed a transient effect within the fibrinolytic pathway. Clinical experience showed that patients who had breaks of therapy longer than a week could not have treatment reinitiated at a dose of 190 mg m-2 without unacceptable toxicity. The 145 mg m-2 dose level is thus the recommended dose for future study.

Phase I/II study of DHA-paclitaxel in combination with carboplatin in patients with advanced malignant solid tumours.

DHA-paclitaxel is a conjugate of paclitaxel and the fatty acid, docosahexaenoic acid. Preclinical studies have demonstrated increased activity, relative to paclitaxel, with the potential for an improved therapeutic ratio. We conducted a phase I study to determine the maximum tolerated doses of DHA-paclitaxel and carboplatin when administered in combination. Two cohorts of patients were treated: carboplatin AUC 5 with DHA-paclitaxel 660 mg m(-2) and carboplatin AUC 5 with DHA-paclitaxel 880 mg m(-2). Both drugs were given on day 1 every 21 days. A total of 15 patients were enrolled with a median age of 59 years (range 33-71). All patients had advanced cancer refractory to standard treatment, performance status 0-2 and were without major organ dysfunction. A total of 54 cycles of treatment were delivered. No dose-limiting toxicity (DLT) was seen in the first cohort of three patients. In an expanded second cohort, neutropenia was the main DLT, occurring in the first cycle of treatment in five of 12 patients: three of these patients and one additional patient also experienced dose-limiting grade 3 transient rises in liver transaminases. No alopecia was seen and one patient developed clinically significant neuropathy. One partial response was seen in a patient with advanced adenocarcinoma of the oesophago-gastric junction and 12 patients had stable disease with a median time to progression of 184 days (range 60-506 days). The recommended phase II dose in pretreated patients is Carboplatin AUC 5 and DHA-paclitaxel 660 mg m(-2) given every 21 days. Further studies with Carboplatin AUC 5 and DHA-paclitaxel 880 mg m(-2), given every 28 days, are warranted in chemo-naive patients.

Phase I and pharmacokinetic study of XR11576, an oral topoisomerase I and II inhibitor, administered on days 1-5 of a 3-weekly cycle in patients with advanced solid tumours.

XR11576 is an oral topoisomerase I and II inhibitor. The objectives of this phase I study were to assess the dose-limiting toxicities (DLTs), to determine the maximum tolerated dose (MTD) and to describe the pharmacokinetics (PKs) of XR11576 when administered orally on days 1-5 every 3 weeks to patients with advanced solid tumours. Patients were treated with escalating doses of XR11576 at doses ranging from 30 to 180 mg day(-1). For PK analysis, plasma sampling was performed during the first and second courses of treatment and XR11576 concentrations were assayed using a validated high-performance liquid chromatographic assay with mass spectrometric detection. In all, 21 patients received a total of 47 courses. The MTD was reached at 180 mg day(-1), with diarrhoea and fatigue as DLT. Nausea and vomiting, although not qualifying for DLT, was ubiquitous. Only in combination with an extensive prophylactic antiemetic regimen consisting of a combination of both dexamethasone and a 5HT3 antagonist was treatment with XR11576 at 120 mg day(-1) tolerable. The systemic exposure of XR11576 increased more than proportionally with increasing dose, with a large interpatient variability. No objective responses were seen; four patients experienced stable disease for periods of 12-30 weeks. In this study, the DLTs of XR11576 were diarrhoea and fatigue. The recommended dose for phase II studies of XR11576 is 120 mg administered orally, on days 1-5 every 21 days. Alternative regimens are currently being explored.

A phase II study of ET-743/trabectedin ('Yondelis') for patients with advanced gastrointestinal stromal tumours.

Primary or secondary resistance to imatinib may occur in patients with gastrointestinal stromal tumours (GISTs) while these tumours have repeatedly been shown to be highly resistant to conventional doxorubicin- and ifosfamide-containing regimens. The investigation of new drugs is therefore warranted in GIST. A phase II study was conducted between May 1999 and November 2000 in eight centres of the EORTC STBSG group to establish the efficacy and safety of ET743 ('Yondelis') in GIST previously untreated with cytotoxic chemotherapy before the imatinib era. ET-743 was given was given at 1.5 mg/m(2) per course as a 24-h continuous intravenous infusion every 3 weeks. Twenty-eight patients were included, 16 males and 12 females. Median age was 54 years (range 25-73 years). Median performance status was 0 (range 0-1). 17 (63%), 4 (12%) and 7 (25%) patients, received 0-2, 3-5, and > or = 6 courses of ET-743, respectively. The best response was stable disease in 9 (33%) patients, and disease progression in 18 patients (67%), with a median time to disease progression and overall survival of 51 days and 589 days, respectively. The treatment was well tolerated: there were grades 3-4 neutropenia, thrombocytopenia, and transaminase increases in 13 (48%), 1 (4%) and 16 (59%) patients, respectively. There were no toxic deaths. ET-743 at this dose and schedule is not an effective treatment for advanced GIST.

Use of c-KIT/PDGFRA mutational analysis to predict the clinical response to imatinib in patients with advanced gastrointestinal stromal tumours entered on phase I and II studies of the EORTC Soft Tissue and Bone Sarcoma Group.

Previous studies have shown that activating mutations of c-KIT/PDGFRA, potential therapeutic targets for imatinib mesylate, are implicated in the pathophysiology of gastrointestinal stromal tumours (GISTs). In this study, GISTs from 37 patients enrolled in an European Organisation for Research and Treatment of Cancer (EORTC) phase I/II clinical study of imatinib were examined for mutations of c-KIT/PDGFRA in order to explore whether the mutational status of the tumour predicts the clinical response to therapy. Mutations were screened by denaturing high-pressure liquid chromatography (DHPLC) and characterised by bi-directional DNA sequencing. Activating mutations of c-KIT or PDGFRA were found in 29 (78%) and 2 (6%) GISTs, respectively. Most c-KIT mutations involved exon 11 (n=24; 83%), all but one being an in-frame deletion; no isolated point mutations were found. The other c-KIT mutations included exon 9 AY 502-503 duplication (n=4; 14%) and exon 13 Lys-->Glu(642) missense mutation (n=1; 3%). Two tumours with no detectable c-KIT mutations demonstrated PDGFRA Asp-->Glu(842) amino acid substitutions. Patients with GISTs harbouring exon 11 mutations were more likely to achieve a partial response (PR) on imatinib therapy (83%) than all of the others (23%). The overall survival and progression-free survival rates for the entire group at 106 weeks were 78.3% and 46.9%, respectively. Based on a Kaplan-Meier analysis, patients with GISTs harbouring c-KIT mutations had longer median survival times and were less likely to progress than the other patients. These findings indicate that the mutational status of the c-KIT/PDGFRA oncoproteins could be useful to predict the clinical response of patients imatinib therapy.