Molecular determinants of the response of glioblastomas to EGFR kinase inhibitors.

BACKGROUND: The epidermal growth factor receptor (EGFR) is frequently amplified, overexpressed, or mutated in glioblastomas, but only 10 to 20 percent of patients have a response to EGFR kinase inhibitors. The mechanism of responsiveness of glioblastomas to these inhibitors is unknown. METHODS: We sequenced kinase domains in the EGFR and human EGFR type 2 (Her2/neu) genes and analyzed the expression of EGFR, EGFR deletion mutant variant III (EGFRvIII), and the tumor-suppressor protein PTEN in recurrent malignant gliomas from patients who had received EGFR kinase inhibitors. We determined the molecular correlates of clinical response, validated them in an independent data set, and identified effects of the molecular abnormalities in vitro. RESULTS: Of 49 patients with recurrent malignant glioma who were treated with EGFR kinase inhibitors, 9 had tumor shrinkage of at least 25 percent. Pretreatment tissue was available for molecular analysis from 26 patients, 7 of whom had had a response and 19 of whom had rapid progression during therapy. No mutations in EGFR or Her2/neu kinase domains were detected in the tumors. Coexpression of EGFRvIII and PTEN was significantly associated with a clinical response (P<0.001; odds ratio, 51; 95 percent confidence interval, 4 to 669). These findings were validated in 33 patients who received similar treatment for glioblastoma at a different institution (P=0.001; odds ratio, 40; 95 percent confidence interval, 3 to 468). In vitro, coexpression of EGFRvIII and PTEN sensitized glioblastoma cells to erlotinib. CONCLUSIONS: Coexpression of EGFRvIII and PTEN by glioblastoma cells is associated with responsiveness to EGFR kinase inhibitors.

Patient-reported treatment satisfaction with oral rivaroxaban versus standard therapy in the treatment of pulmonary embolism; results from the EINSTEIN PE trial.

INTRODUCTION: Rivaroxaban is an oral, direct Factor Xa inhibitor, approved for the treatment of pulmonary embolism (PE) and deep vein thrombosis (DVT) and the secondary prevention of recurrent PE and DVT as a fixed-dose, monotherapy regimen that does not require initial heparinisation, routine coagulation monitoring or dose adjustment. Approval in this indication was supported by results from EINSTEIN PE, a large, randomised, open-label study that compared rivaroxaban with enoxaparin/vitamin K antagonist (VKA) therapy in patients with acute symptomatic PE with or without DVT. MATERIALS AND METHODS: Patient-reported treatment satisfaction was evaluated in a predefined subanalysis of EINSTEIN PE to enable monitoring and optimisation of patient-reported outcomes and, therefore, patient compliance. As part of EINSTEIN PE, 2,397 patients in seven countries were asked to complete a validated measure of treatment satisfaction, the Anti-Clot Treatment Scale (ACTS) throughout the duration of treatment (up to 12 months). RESULTS: Patients reported greater satisfaction in the rivaroxaban treatment arm as compared with the enoxaparin/VKA treatment arm. Treatment with rivaroxaban was reported as being significantly less burdensome than enoxaparin/VKA therapy, and the benefits of treatment were significantly greater. CONCLUSION: Rivaroxaban treatment resulted in improved treatment satisfaction compared with enoxaparin/VKA in PE patients, particularly in reducing patient-reported anticoagulation burden.

Asteroid hyalosis in an older population: the Blue Mountains Eye Study.

PURPOSE: To assess the prevalence of and associations with asteroid hyalosis in an older population. METHODS: The Blue Mountains Eye Study was a cross-sectional study of an older community (aged 49-97 years). Subjects included were those attending the baseline (n = 3654) and 5-year examinations (n = 2335) of this cohort. Asteroid hyalosis was diagnosed clinically by the presence of cream-white spherical bodies within the vitreous or from grading of stereo retinal photographs of both eyes. Logistic regression assessed age-sex adjusted associations with relevant characteristics, including diabetes and cardiovascular variables. RESULTS: Asteroid hyalosis was found in 36 subjects (1.0%), 95% confidence interval (CI) 0.7% to 1.3%, and was bilateral in three affected subjects (8.3%). An age-related increase in prevalence was observed, increasing from 0% of persons aged less than 55 years to 2.1% of persons aged 75 years or older. The prevalence of this sign was significantly higher in men (1.4%) than in women (0.6%), the age-adjusted odds ratio (OR) was 2.54 (CI 1.25-5.16). No statistically significant associations were found between asteroid hyalosis and a history of heart disease, gout, current smoking, the highest level of alcohol consumption or with presence of diabetes (diagnosed from history or fasting blood glucose tests). CONCLUSIONS: Asteroid hyalosis was detected in 1% of participants in this Australian older population. No significant associations were found, apart from age and male gender. Our study provides similar age-specific prevalence data to a recent report from the Beaver Dam Eye Study for asteroid hyalosis.

Patient-reported treatment satisfaction with oral rivaroxaban versus standard therapy in the treatment of acute symptomatic deep-vein thrombosis.

Rivaroxaban, an oral, direct factor Xa inhibitor, has been approved for the treatment of deep-vein thrombosis (DVT) and pulmonary embolism (PE) and the prevention of recurrent DVT and PE as a fixed-dose, single-drug regimen that does not require initial heparinisation, routine coagulation monitoring or dose adjustment. This study evaluated patient-reported treatment satisfaction in EINSTEIN DVT--a large, open-label, randomised study that compared rivaroxaban with enoxaparin/vitamin K antagonist (VKA) therapy in patients with acute symptomatic DVT without PE. As part of EINSTEIN DVT, a total of 1,472 patients in seven countries were asked to complete a new, validated measure of treatment satisfaction--the Anti-Clot Treatment Scale (ACTS)--at scheduled visits throughout 12 months of treatment. ACTS scores were compared between study groups in the intention-to-treat population. Patients reported greater satisfaction in the rivaroxaban group compared with the enoxaparin/VKA group, with higher mean ACTS scores across visits. Mean ACTS Burdens scores were 55.2 vs 52.6 (p<0.0001) in favour of rivaroxaban, equivalent to a moderate effect size of 0.42. The treatment effect was consistent over time, with the mean score difference ranging from 2.18 (month 2) to 3.18 (month 12). Overall mean ACTS Benefits scores were 11.7 vs 11.5 in favour of rivaroxaban (p=0.006). This was associated with a small overall effect size of 0.12. The improvement in ACTS Benefits for rivaroxaban became apparent at month 2 and subsequent visits. Rivaroxaban results in improved treatment satisfaction compared with enoxaparin/VKA among patients with DVT, particularly in reducing patient-reported anticoagulation burden.

Mammalian target of rapamycin inhibition promotes response to epidermal growth factor receptor kinase inhibitors in PTEN-deficient and PTEN-intact glioblastoma cells.

The epidermal growth factor receptor (EGFR) is commonly amplified, overexpressed, and mutated in glioblastoma, making it a compelling molecular target for therapy. We have recently shown that coexpression of EGFRvIII and PTEN protein by glioblastoma cells is strongly associated with clinical response to EGFR kinase inhibitor therapy. PTEN loss, by dissociating inhibition of the EGFR from downstream phosphatidylinositol 3-kinase (PI3K) pathway inhibition, seems to act as a resistance factor. Because 40% to 50% of glioblastomas are PTEN deficient, a critical challenge is to identify strategies that promote responsiveness to EGFR kinase inhibitors in patients whose tumors lack PTEN. Here, we show that the mammalian target of rapamycin (mTOR) inhibitor rapamycin enhances the sensitivity of PTEN-deficient tumor cells to the EGFR kinase inhibitor erlotinib. In two isogenic model systems (U87MG glioblastoma cells expressing EGFR, EGFRvIII, and PTEN in relevant combinations, and SF295 glioblastoma cells in which PTEN protein expression has been stably restored), we show that combined EGFR/mTOR kinase inhibition inhibits tumor cell growth and has an additive effect on inhibiting downstream PI3K pathway signaling. We also show that combination therapy provides added benefit in promoting cell death in PTEN-deficient tumor cells. These studies provide strong rationale for combined mTOR/EGFR kinase inhibitor therapy in glioblastoma patients, particularly those with PTEN-deficient tumors.

Differential induction of glioblastoma migration and growth by two forms of pleiotrophin.

Glioblastoma is the most common malignant brain tumor of adults and one of the most lethal cancers. The secreted growth factor pleiotrophin (PTN) promotes glioblastoma migration and proliferation, initiating its oncogenic activities through two cell surface receptors, the protein tyrosine phosphatase receptor zeta (PTPRZ1) and the anaplastic lymphoma kinase (ALK), respectively. Here, we report on the presence and purification of two naturally occurring forms of PTN (18 and 15 kDa) that differentially promote glioblastoma migration and proliferation. Using a panel of glioblastoma cell lines, including low passage patient-derived cultures, we demonstrate that PTN15 promotes glioblastoma proliferation in an ALK-dependent fashion, whereas immobilized PTN18 promotes haptotactic migration of glioblastoma cells in a PTPRZ1-dependent fashion. Mass spectrometric analysis indicated that PTN15 differs from PTN18 by processing of 12 C-terminal amino acids. To demonstrate clinical relevance, we show that PTN15, PTN18, and PTPRZ1 are significantly overexpressed in glioblastoma relative to normal brain at both mRNA and protein levels using microarray, Western blot, and tissue microarray analyses on human tumors. These results indicate that the PTN18-PTPRZ1 and the PTN15-ALK signaling pathways represent potentially important therapeutic targets for glioblastoma invasion and growth.