Publications by authors named "Mathias Muth"

Background: Breast cancer and its treatments are associated with a detrimental effect on bone health. Here we report the results of an exploratory analysis assessing changes in levels of biomarkers of bone metabolism in patients enrolled in the phase IIIb 4EVER study.

Methods: The 4EVER trial investigated everolimus in combination with exemestane in postmenopausal women with hormone receptor-positive, human epidermal growth factor receptor 2-negative locally advanced or metastatic breast cancer.

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In BOLERO-2, adding everolimus to exemestane resulted in a twofold increase in median progression-free survival (PFS) vs exemestane in postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (aBC) after progression on a non-steroidal aromatase inhibitor (NSAI). Here, we report on the open-label, single-arm, phase IIIB 4EVER trial (NCT01626222). This trial evaluated the clinical effectiveness of everolimus plus exemestane in postmenopausal women with HR+, HER2- aBC who had progressed on or after an NSAI, but with no restrictions on the time of progression after NSAI, prior chemotherapy for advanced disease or previous exemestane.

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Protean agonists are of great pharmacological interest as their behavior may change in magnitude and direction depending on the constitutive activity of a receptor. Yet, this intriguing phenomenon has been poorly described and understood, due to the lack of stable experimental systems and design strategies. In this study, we overcome both limitations: First, we demonstrate that modulation of the ionic strength in a defined experimental set-up allows for analysis of G protein-coupled receptor activation in the absence and presence of a specific amount of spontaneous receptor activity using the muscarinic M acetylcholine receptor as a model.

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Background: Imatinib is a tyrosine kinase inhibitor of BCR-ABL, ABL, PDGFR-α and -β, KIT, and DDR. In solid tumors, it inhibits proliferation and invasiveness and facilitates higher intratumoral cytotoxic drug concentrations. Vinorelbine has good tolerability and efficacy in metastatic breast cancer (MBC).

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Endocrine therapy (ET) is a key treatment modality in hormone receptor positive (HR+) early breast cancer (BC) patients. Although the anticancer activity of adjuvant ET + zoledronic acid (ZOL) has been investigated, the potential effects of ET ± ZOL on endocrine hormones in premenopausal women with HR+ early BC are not well understood. ProBONE II was prospective, double-blind, randomized controlled trial.

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Background: The objective of this prospectively randomized phase II trial (Trial registration: EUCTR2004-004007-37-DE) was to compare the clinical response of primary breast cancer patients to neoadjuvant therapy with letrozole alone (LET) or letrozole and zoledronic acid (LET + ZOL).

Methods: Patients were randomly assigned to receive either LET 2.5 mg/day (n = 79) or the combination of LET 2.

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We present a new concept of partial agonism at G protein-coupled receptors. We demonstrate the coexistence of two functionally distinct populations of the muscarinic M2 receptor stabilized by one dynamic ligand, which binds in two opposite orientations. The ratio of orientations determines the cellular response.

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Purpose: The ZOTECT study assesses the effect of zoledronic acid (ZOL) on bone-marker levels and potential correlations with disease outcomes in bisphosphonate-naive patients.

Methods: This prospective, single-arm, open-label study in bisphosphonate-naive (≥6 months) patients with bone metastases from prostate cancer (PC; n=301) or breast cancer (BC; n=99) enrolled at 98 German sites (May 2006 to July 2008) investigated the effect of ZOL (4 mg intravenously every 4 weeks×4 months, with a final follow-up at 12 months) on bone-marker levels. Secondary assessments: skeletal-related event (SRE) rate, pain, quality of life (QoL), and prostate-specific antigen levels.

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Selective modulation of cell function by G protein-coupled receptor (GPCR) activation is highly desirable for basic research and therapy but difficult to achieve. We present a novel strategy toward this goal using muscarinic acetylcholine receptors as a model. The five subtypes bind their physiological transmitter in the highly conserved orthosteric site within the transmembrane domains of the receptors.

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COPD represents an underestimated and underdiagnosed disease with an enormous socioeconomic impact. Cigarette smoking is the main risk factor for the development of COPD. For this reason, prevention and smoking cessation form the mainstays of COPD therapy.

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Sleeping sickness caused by Trypanosoma brucei gambiense and rhodesiense is fatal if left untreated. Due to the toxicity of drugs currently used and the emerging resistance against these drugs new lead compounds are urgently needed. Within the frame of a broad screening program for drugs with antitrypanosomal activity, some highly potent tertiary and quaternary mono- and bisnaphthalimides being active in the lower micromolar and nanomolar range of concentration have been identified.

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A novel series of muscarinic receptor ligands of the hexamethonio-type was prepared which contained, on one side, the phthalimidopropane or 1,8-naphthalimido-2,2-dimethylpropane moiety typical for subtype selective allosteric antagonists and, on the other, the acetylenic fragment typical for the nonselective orthosteric muscarinic agonists oxotremorine, oxotremorine-M, and related muscarinic agonists. Binding experiments in M(2) receptors using [(3)H]N-methylscopolamine as an orthosteric probe proved an allosteric action of both groups of hybrids, 7a-10a and 8b-10b. The difference in activity between a-group and b-group hybrids corresponded with the activity difference between the allosteric parent compounds.

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Bisphthalimidopropyl-substituted hexamethonio compounds have been established as allosteric modulators of ligand binding to muscarinic acetylcholine receptors. Enhancers of ligand binding are of special interest. This study aimed to unravel the structural elements inducing positive cooperativity with the binding of an antagonist.

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Bis(ammonio)alkane compounds carrying lateral phthalimidopropyl substituents on the nitrogen atoms belong to the archetypal muscarinic allosteric agents. Herein, a series of symmetrical and nonsymmetrical compounds was synthesized in which the phthalimide residues were replaced by differently substituted imide moieties. The allosteric action was measured in porcine heart muscarinic M(2) receptors using [(3)H]N-methylscopolamine (NMS) as a ligand for the orthosteric receptor site in equilibrium binding and dissociation experiments.

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