Pathway analysis of glioblastoma tissue after preoperative treatment with the EGFR tyrosine kinase inhibitor gefitinib--a phase II trial.

Amplification of the epidermal growth factor receptor (EGFR) gene is one of the most common oncogenic alterations in glioblastoma (45%) making it a prime target for therapy. However, small molecule inhibitors of the EGFR tyrosine kinase showed disappointing efficacy in clinical trials for glioblastoma. Here we aimed at investigating the molecular effects of the tyrosine kinase inhibitor gefitinib on the EGFR signaling pathway in human glioblastoma. Twenty-two patients selected for reoperation of recurrent glioblastoma were treated within a phase II trial for 5 days with 500 mg gefitinib before surgery followed by postoperative gefitinib until recurrence. Resected glioblastoma tissues exhibited high concentrations of gefitinib (median, 4.1 μg/g), 20 times higher than respective plasma. EGFR-pathway activity was evaluated with phosphorylation-specific assays. The EGFR was efficiently dephosphorylated in treated patients as compared to a control cohort of 12 patients. However, no significant effect on 12 pathway constituents was detected. In contrast, in vitro treatment of a glioblastoma cell line, BS-153, with endogenous EGFRwt amplification and EGFRvIII expression resulted not only in dephosphorylation of the EGFR, but also of key regulators in the pathway such as AKT. Treating established xenografts of the same cell line as an in vivo model showed dephosphorylation of the EGFR without affecting downstream signal transductors, similar to the human glioblastoma. Taken together, gefitinib reaches high concentrations in the tumor tissue and efficiently dephosphorylates its target. However, regulation of downstream signal transducers in the EGFR pathway seems to be dominated by regulatory circuits independent of EGFR phosphorylation.

Access of extracellular cations to their binding sites in Na,K-ATPase: role of the second extracellular loop of the alpha subunit.

Na,K-ATPase, the main active transport system for monovalent cations in animal cells, is responsible for maintaining Na(+) and K(+) gradients across the plasma membrane. During its transport cycle it binds three cytoplasmic Na(+) ions and releases them on the extracellular side of the membrane, and then binds two extracellular K(+) ions and releases them into the cytoplasm. The fourth, fifth, and sixth transmembrane helices of the alpha subunit of Na,K-ATPase are known to be involved in Na(+) and K(+) binding sites, but the gating mechanisms that control the access of these ions to their binding sites are not yet fully understood. We have focused on the second extracellular loop linking transmembrane segments 3 and 4 and attempted to determine its role in gating. We replaced 13 residues of this loop in the rat alpha1 subunit, from E314 to G326, by cysteine, and then studied the function of these mutants using electrophysiological techniques. We analyzed the results using a structural model obtained by homology with SERCA, and ab initio calculations for the second extracellular loop. Four mutants were markedly modified by the sulfhydryl reagent MTSET, and we investigated them in detail. The substituted cysteines were more readily accessible to MTSET in the E1 conformation for the Y315C, W317C, and I322C mutants. Mutations or derivatization of the substituted cysteines in the second extracellular loop resulted in major increases in the apparent affinity for extracellular K(+), and this was associated with a reduction in the maximum activity. The changes produced by the E314C mutation were reversed by MTSET treatment. In the W317C and I322C mutants, MTSET also induced a moderate shift of the E1/E2 equilibrium towards the E1(Na) conformation under Na/Na exchange conditions. These findings indicate that the second extracellular loop must be functionally linked to the gating mechanism that controls the access of K(+) to its binding site.

Effect of inspiratory threshold loading on ventilatory kinetics during constant-load exercise.

Humoral factors play an important role in the control of exercise hyperpnea. The role of neuromechanical ventilatory factors, however, is still being investigated. We tested the hypothesis that the afferents of the thoracopulmonary system, and consequently of the neuromechanical ventilatory loop, have an influence on the kinetics of oxygen consumption (VO2), carbon dioxide output (VCO2), and ventilation (VE) during moderate intensity exercise. We did this by comparing the ventilatory time constants (tau) of exercise with and without an inspiratory load. Fourteen healthy, trained men (age 22.6 +/- 3.2 yr) performed a continuous incremental cycle exercise test to determine maximal oxygen uptake (VO2max = 55.2 +/- 5.8 ml x min(-1) x kg(-1)). On another day, after unloaded warm-up they performed randomized constant-load tests at 40% of their VO2max for 8 min, one with and the other without an inspiratory threshold load of 15 cmH2O. Ventilatory variables were obtained breath by breath. Phase 2 ventilatory kinetics (VO2, VCO2, and VE) could be described in all cases by a monoexponential function. The bootstrap method revealed small coefficients of variation for the model parameters, indicating an accurate determination for all parameters. Paired Student's t-tests showed that the addition of the inspiratory resistance significantly increased the tau during phase 2 of VO2 (43.1 +/- 8.6 vs. 60.9 +/- 14.1 s; P < 0.001), VCO2 (60.3 +/- 17.6 vs. 84.5 +/- 18.1 s; P < 0.001) and VE (59.4 +/- 16.1 vs. 85.9 +/- 17.1 s; P < 0.001). The average rise in tau was 41.3% for VO2, 40.1% for VCO2, and 44.6% for VE. The tau changes indicated that neuromechanical ventilatory factors play a role in the ventilatory response to moderate exercise.

Evaluation der Nationalen Krebsbekämpfungsprogramme, Phase I, 1999. Studie 3: Konzeptualisierung und Stand der Umsetzung der vier Krebsbekämpfungsprogramme

[Table des matières] 1. Zusammenfassung und Empfehlungen. 2. Einleitung. 2.1. Hintergrund der Nationalen Krebsbekämpfungsprogramme. 2.2. Grundlagen der Konzeptualisierung der vier Programme. 3. Nationales Programm zur Bekämpfung des Brustkrebses, des Hautkrebses, des Lungkrebses, des Darmkrebses : Beschreibung und beurteilung der Konzeptualisierung des Programms und Schlussfolgerungen und Empfehlungen. 4. Programmübergreifende Aspekte. 5. Chronologische Ubersicht der vier nationalen Krebsbekämpfungsprogramme. 6. Liste des Interviews, welche im Rahmen der Studie 3 der Evaluation der Nationalen Krebsbekämpfungs-Programme durchgeführt wurden. 7. Geplante Realisierung von Zielen in den Bereichen : Gesundheitsförderung und Prävention, Sekundärprävention, Therapie und Nachsorge durch das Programm Brustkrebs. 8. Evaluationsstudien. 9. Raster Umsetzung der Programmbausteine.

Reciprocal regulation of brain and muscle Arnt-like protein 1 and peroxisome proliferator-activated receptor alpha defines a novel positive feedback loop in the rodent liver circadian clock.

Recent evidence has emerged that peroxisome proliferator-activated receptor alpha (PPARalpha), which is largely involved in lipid metabolism, can play an important role in connecting circadian biology and metabolism. In the present study, we investigated the mechanisms by which PPARalpha influences the pacemakers acting in the central clock located in the suprachiasmatic nucleus and in the peripheral oscillator of the liver. We demonstrate that PPARalpha plays a specific role in the peripheral circadian control because it is required to maintain the circadian rhythm of the master clock gene brain and muscle Arnt-like protein 1 (bmal1) in vivo. This regulation occurs via a direct binding of PPARalpha on a potential PPARalpha response element located in the bmal1 promoter. Reversely, BMAL1 is an upstream regulator of PPARalpha gene expression. We further demonstrate that fenofibrate induces circadian rhythm of clock gene expression in cell culture and up-regulates hepatic bmal1 in vivo. Together, these results provide evidence for an additional regulatory feedback loop involving BMAL1 and PPARalpha in peripheral clocks.

EORTC study 26041-22041: phase I/II study on concomitant and adjuvant temozolomide (TMZ) and radiotherapy (RT) with PTK787/ZK222584 (PTK/ZK) in newly diagnosed glioblastoma.

BACKGROUND: Glioblastoma is a highly vascularised tumour with a high expression of both vascular endothelial growth factor (VEGF) and VEGFR. PTK787/ZK222584 (PTK/ZK, vatalanib), a multiple VEGF receptor inhibitor, blocks the intracellular tyrosine kinase activity of all known VEGF receptors and is therefore suitable for long-term therapy of pathologic tumour neovascularisation. PATIENTS AND METHODS: The study was designed as an open-label, phase I/II study. A classic 3+3 design was selected. PTK/ZK was added to standard concomitant and adjuvant treatment, beginning in the morning of day 1 of radiotherapy (RT), and given continuously until disease progression or toxicity. PTK/ZK doses started from 500 mg with subsequent escalations to 1000 and 1250 mg/d. Adjuvant or maintenance PTK after the end of radiochemotherapy was given at a previously established dose of 750 mg twice daily continuously with TMZ at the standard adjuvant dose. RESULTS: Twenty patients were enrolled. Dose-limiting toxicities at a once daily dose of 1250 mg were grade 3 diarrhoea (n=1), grade 3 ALT increase (n=2), and myelosuppression with grade 4 thrombocytopenia and neutropenia (n=1). The recommended dose of PTK/ZK in combination with radiotherapy and temozolomide (TMZ) is 1000 mg once a day. This treatment is safe and well tolerated. CONCLUSION: In our phase I study once daily administration of up to 1000 mg of PTK/ZK in conjunction with concomitant temozolomide and radiotherapy was feasible and safe. Prolonged administration of this oral agent is manageable. The planned randomised phase II trial was discontinued right at its onset due to industry decision not to further develop this agent.

Appropriate end-points for right results in the age of antiangiogenic agents: Future options for phase II trials in patients with recurrent glioblastoma.

The progression-free survival rate at 6months (PFS-6) has long been considered the best end-point for assessing the efficacy of new agents in phase II trials in patients with recurrent glioblastoma. However, due to the introduction of antiangiogenic agents in this setting, and their intrinsic propensity to alter neuroradiological disease assessment by producing pseudoregression, any end-point based on neuroradiological modifications should be reconsidered. Further, statistically significant effects on progression-free survival (PFS) only should not automatically be considered reliable evidence of meaningful clinical benefit. In this context, because of its direct and unquestionable clinical relevance, overall survival (OS) represents the gold standard end-point for measuring clinical efficacy, despite the disadvantage that it is influenced by subsequent therapies and usually takes longer time to be evaluated. Therefore, while awaiting novel imaging criteria for response evaluation and/or new imaging tools to distinguish between 'true' and 'pseudo'-responses to antiangiogenic agents, the measurement of OS or OS rates should be considered primary end-points, also in phase II trials with these agents.

Efficacy of cetuximab in metastatic castration-resistant prostate cancer might depend on EGFR and PTEN expression: results from a phase II trial (SAKK 08/07).

PURPOSE: The EGF receptor (EGFR) is overexpressed in the majority of metastatic castration-resistant prostate cancers (mCRPC) and might represent a valid therapeutic target. The combination of docetaxel and cetuximab, the monoclonal antibody against EGFR, has not been tested in patients with prostate cancer. EXPERIMENTAL DESIGN: Patients with mCRPC progressing during or within 90 days after at least 12 weeks of docetaxel were included in this phase II trial. Treatment consisted of docetaxel (75 mg/m(2) every 3 weeks or 35 mg/m(2) on days 1, 8, 15 every 4 weeks) in combination with cetuximab (400 mg/m(2) on day 1 and then 250 mg/m(2) weekly). The primary endpoint was progression-free survival (PFS) at 12 weeks defined as the absence of prostate-specific antigen (PSA), radiographic, or clinical progression. Evaluation of known biomarkers of response and resistance to cetuximab (EGFR, PTEN, amphiregulin, epiregulin) was conducted. RESULTS: Thirty-eight patients were enrolled at 15 Swiss centers. Median age was 68 years and median PSA was 212 ng/mL. PFS at 12 weeks was 34% [95% confidence interval (CI), 19%-52%], PFS at 24 weeks was 20%, and median overall survival (OS) was 13.3 months (95% CI, 7.3-15.4). Seven patients (20%) had a confirmed ≥ 50% and 11 patients (31%) a confirmed ≥ 30% PSA decline. About 47% of enrolled patients experienced grade 3 and 8% grade 4 toxicities. A significantly improved PFS was found in patients with overexpression of EGFR and persistent activity of PTEN. CONCLUSIONS: EGFR inhibition with cetuximab might improve the outcome of patients with mCRPC. A potential correlation between EGFR overexpression, persistent expression of PTEN, and EGFR inhibition should be investigated further.

Y-90 Ibritumomab Tiuxetan (Zevalin (R)) Consolidation of First Remission In Advanced Stage Follicular Non Hodgkin's Lymphoma Updated Results After a Median Follow up of 662 Months From the International, Randomized, Phase III First Line Indolent Trial (FIT) In 414 Patients

The FIT trial was conducted to evaluate the safety and efficacy of 90Y-ibritumomab tiuxetan (0.4 mCi/kg; maximum dose 32 mCi) when used as consolidation of first complete or partial remission in patients with previously untreated, advanced-stage follicular lymphoma (FL). Patients were randomly assigned to either 90Y-ibritumomab treatment (n = 207) or observation (n = 202) within 3 months (mo) of completing initial induction therapy (chemotherapy only: 86%; rituximab in combination with chemotherapy: 14%). Response status prior to randomization did not differ between the groups: 52% complete response (CR)/CR unconfirmed (CRu) to induction therapy and 48% partial response (PR) in the 90Y-ibritumomab arm vs 53% CR/CRu and 44% PR in the control arm. The primary endpoint was progression-free survival (PFS) of the intent-to-treat (ITT) population. Results from the first extended follow-up after a median of 3.5 years revealed a significant improvement in PFS from the time of randomization with 90Y-ibritumomab consolidation compared with control (36.5 vs 13.3 mo, respectively; P < 0.0001; Morschhauser et al. JCO. 2008; 26:5156-5164). Here we report a median follow-up of 66.2 mo (5.5 years). Five-year PFS was 47% in the 90Y-ibritumomab group and 29% in the control group (hazard ratio (HR) = 0.51, 95% CI 0.39-0.65; P < 0.0001). Median PFS in the 90Y-ibritumomab group was 49 mo vs 14 mo in the control group. In patients achieving a CR/CRu after induction, 5-year PFS was 57% in the 90Y-ibritumomab group, and the median had not yet been reached at 92 months, compared with a 43% 5-year PFS in the control group and a median of 31 mo (HR = 0.61, 95% CI 0.42-0.89). For patients in PR after induction, the 5-year PFS was 38% in the 90Y-ibritumomab group with a median PFS of 30 mo vs 14% in the control group with a median PFS of 6 mo (HR = 0.38, 95% CI 0.27-0.53). Patients who had received rituximab as part of induction treatment had a 5-year PFS of 64% in the 90Y-ibritumomab group and 48% in the control group (HR = 0.66, 95% CI 0.30-1.47). For all patients, time to next treatment (as calculated from the date of randomization) differed significantly between both groups; median not reached at 99 mo in the 90Y-ibritumomab group vs 35 mo in the control group (P < 0.0001). The majority of patients received rituximab-containing regimens when treated after progression (63/82 [77%] in the 90Y-ibritumomab group and 102/122 [84%] in the control group). Overall response rate to second-line treatment was 79% in the 90Y-ibritumomab group (57% CR/CRu and 22% PR) vs 78% in the control arm (59% CR/CRu, 19% PR). Five-year overall survival was not significantly different between the groups; 93% and 89% in the 90Y-ibritumomab and control groups, respectively (P = 0.561). To date, 40 patients have died; 18 in the 90Y-ibritumomab group and 22 in the control group. Secondary malignancies were diagnosed in 16 patients in the 90Y-ibritumomab arm vs 9 patients in the control arm (P = 0.19). There were 6 (3%) cases of myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML) in the 90Y-ibritumomab arm vs 1 MDS in the control arm (P = 0.063). In conclusion, this extended follow-up of the FIT trial confirms the benefit of 90Y-ibritumomab consolidation with a nearly 3 year advantage in median PFS. A significant 5-year PFS improvement was confirmed for patients with a CR/CRu or a PR after induction. Effective rescue treatment with rituximab-containing regimens may explain the observed no difference in overall survival between both patient groups who were - for the greater part - rituximab-naïve.

Complete longitudinal analyses of the randomized, placebo-controlled, phase III trial of sunitinib in patients with gastrointestinal stromal tumor following imatinib failure.

PURPOSE: To analyze final long-term survival and clinical outcomes from the randomized phase III study of sunitinib in gastrointestinal stromal tumor patients after imatinib failure; to assess correlative angiogenesis biomarkers with patient outcomes. EXPERIMENTAL DESIGN: Blinded sunitinib or placebo was given daily on a 4-week-on/2-week-off treatment schedule. Placebo-assigned patients could cross over to sunitinib at disease progression/study unblinding. Overall survival (OS) was analyzed using conventional statistical methods and the rank-preserving structural failure time (RPSFT) method to explore cross-over impact. Circulating levels of angiogenesis biomarkers were analyzed. RESULTS: In total, 243 patients were randomized to receive sunitinib and 118 to placebo, 103 of whom crossed over to open-label sunitinib. Conventional statistical analysis showed that OS converged in the sunitinib and placebo arms (median 72.7 vs. 64.9 weeks; HR, 0.876; P = 0.306) as expected, given the cross-over design. RPSFT analysis estimated median OS for placebo of 39.0 weeks (HR, 0.505, 95% CI, 0.262-1.134; P = 0.306). No new safety concerns emerged with extended sunitinib treatment. No consistent associations were found between the pharmacodynamics of angiogenesis-related plasma proteins during sunitinib treatment and clinical outcome. CONCLUSIONS: The cross-over design provided evidence of sunitinib clinical benefit based on prolonged time to tumor progression during the double-blind phase of this trial. As expected, following cross-over, there was no statistical difference in OS. RPSFT analysis modeled the absence of cross-over, estimating a substantial sunitinib OS benefit relative to placebo. Long-term sunitinib treatment was tolerated without new adverse events.