We describe the discovery and the structure-activity relationship of a new series of quinoline derivatives acting as selective and highly potent noncompetitive mGlu1 antagonists. We first identified cis-10 as a fairly potent mGlu1 antagonist (IC(50) = 20 nM) in a cell-based signal transduction assay on the rat mGlu1 receptor expressed in CHO-K1 cells, and then we were able to design and synthesize highly potent compounds on both rat and human mGlu1 receptors as exemplified by compound cis-64a, which has an antagonist potency of 0.5 nM for the human mGlu1 receptor. We briefly present and discuss the in vitro metabolic stability of the compounds in human liver microsomes. We finally report the pharmacokinetic properties of our lead compound cis-64a.

This article is available online at http://dmd.aspetjournals.org ABSTRACT:Galantamine is a competitive acetylcholine esterase inhibitor with a beneficial therapeutic effect in patients with Alzheimer's disease. The metabolism and excretion of orally administered 3 H-labeled galantamine was investigated in rats and dogs at a dose of 2.5 mg base-Eq/kg body weight and in humans at a dose of 4 mg base-Eq. Both poor and extensive metabolizers of CYP2D6 were included in the human study. Urine, feces, and plasma samples were collected for up to 96 h (rats) or 168 h (dogs and humans) after dosing. The radioactivity of the samples and the concentrations of galantamine and its major metabolites were analyzed. In all species, galantamine and its metabolites were predominantly excreted in the urine (from 60% in male rats to 93% in humans). Excretion of radioactivity was rapid and nearly complete at 96 h after dosing in all species. Major metabolic pathways were glucuronidation, Odemethylation, N-demethylation, N-oxidation, and epimerization. All metabolic pathways observed in humans occurred in at least one animal species. In extensive metabolizers for CYP2D6, urinary metabolites resulting from O-demethylation represented 33.2% of the dose compared with 5.2% in poor metabolizers, which showed correspondingly higher urinary excretion of unchanged galantamine and its N-oxide. The glucuronide of O-desmethyl-galantamine represented up to 19% of the plasma radioactivity in extensive metabolizers but could not be detected in poor metabolizers. Nonvolatile radioactivity and unchanged galantamine plasma kinetics were similar for poor and extensive metabolizers. Genetic polymorphism in the expression of CYP2D6 is not expected to affect the pharmacodynamics of galantamine.

Purpose: Originally isolated on the basis of its ability to induce p53, serdemetan showed potent activity in various preclinical models, inducing S-phase arrest and apoptosis in TP53 wild-type and mutant tumors. This study evaluated the safety and tolerability of serdemetan, determined the pharmacokinetic and pharmacodynamic profiles, and identified a recommended phase II dose.Patients and Methods: Patients (71) with refractory solid tumors were allocated to dose-escalating cohorts (3þ3 patients each) and received oral serdemetan once daily in 21-day cycles to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT). Plasma was collected for pharmacokinetic analyses. Paired baseline and on-treatment skin and tumor biopsies were done; blood samples were collected for pharmacodynamic analyses, including p53 and macrophage inhibitory cytokine-1 induction.Results: The MTD of serdemetan was determined to be 350 mg once daily. During this study, grade 3 QTc prolongation was the most common DLT and nausea (66.2%) was the most frequent treatment-emergent adverse event. Serdemetan was rapidly absorbed after oral administration and exhibited dose-proportional pharmacokinetics. At steady state, mean maximum plasma concentration (C max ) was 2,330 ng/mL and mean area under plasma concentration curve (AUC 0-24h ) was 43.0 mg.h/mL, with serdemetan 300 mg/d. There was a dose-and exposure-dependent p53 induction. One patient with breast cancer showed a partial response; 22 (38.6%) patients had stable disease.Conclusions: Serdemetan treatment was associated with p53 induction in both tumor and surrogate tissue pharmacodynamic studies and modest clinical activity. Although serdemetan was well tolerated with dose-proportional pharmacokinetics, exposure-related QTc liability was observed.