Lumiracoxib 400 mg once daily is comparable to indomethacin 50 mg three times daily for the treatment of acute flares of gout.

OBJECTIVES: To demonstrate non-inferiority of lumiracoxib 400 mg once daily (o.d.) compared with indomethacin 50 mg three times daily (t.i.d.) in the treatment of acute gout, and to compare the safety and tolerability of these treatments. METHODS: In this 1-week, multicentre, randomized, double-blind, double-dummy, active-controlled, parallel-group study, patients with a clinical diagnosis of gout, an acute attack of gout in four or more joints within the 48 h prior to evaluation, and at least moderate pain intensity in the target joint were randomized to treatment with lumiracoxib 400 mg o.d. (n = 118) or indomethacin 50 mg t.i.d. (n = 117). The primary efficacy endpoint was the mean change in pain intensity from baseline over days 2-5, assessed on a 5-point Likert scale, where non-inferiority could be claimed if the lower limit of the confidence interval (CI) was greater than -0.5. The patient's and physician's global assessment of response to treatment, and physician's assessment of tenderness, swelling and erythema of the study joint were also assessed. RESULTS: The estimated difference between treatments for the change from baseline in pain intensity over days 2-5 was -0.004 (95% CI -0.207 to 0.199, P > 0.05), indicating that lumiracoxib 400 mg o.d. had comparable efficacy to indomethacin 50 mg t.i.d. for the primary efficacy variable. There was no significant difference between treatments in any of the secondary efficacy variables. Adverse events were reported by 10.2% of patients treated with lumiracoxib and 22.2% of those receiving indomethacin. CONCLUSIONS: Lumiracoxib is as effective as indomethacin for treatment of acute gout and may have a better safety and tolerability profile.

The non-competitive antagonists 2-methyl-6-(phenylethynyl)pyridine and 7-hydroxyiminocyclopropan[b]chromen-1a-carboxylic acid ethyl ester interact with overlapping binding pockets in the transmembrane region of group I metabotropic glutamate receptors.

We have investigated the mechanism of inhibition and site of action of the novel human metabotropic glutamate receptor 5 (hmGluR5) antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP), which is structurally unrelated to classical metabotropic glutamate receptor (mGluR) ligands. Schild analysis indicated that MPEP acts in a non-competitive manner. MPEP also inhibited to a large extent constitutive receptor activity in cells transiently overexpressing rat mGluR5, suggesting that MPEP acts as an inverse agonist. To investigate the molecular determinants that govern selective ligand binding, a mutagenesis study was performed using chimeras and single amino acid substitutions of hmGluR1 and hmGluR5. The mutants were tested for binding of the novel mGluR5 radioligand [(3)H]2-methyl-6-(3-methoxyphenyl)ethynyl pyridine (M-MPEP), a close analog of MPEP. Replacement of Ala-810 in transmembrane (TM) VII or Pro-655 and Ser-658 in TMIII with the homologous residues of hmGluR1 abolished radioligand binding. In contrast, the reciprocal hmGluR1 mutant bearing these three residues of hmGluR5 showed high affinity for [(3)H]M-MPEP. Radioligand binding to these mutants was also inhibited by 7-hydroxyiminocyclopropan[b]chromen-1a-carboxylic acid ethyl ester (CPCCOEt), a structurally unrelated non-competitive mGluR1 antagonist previously shown to interact with residues Thr-815 and Ala-818 in TMVII of hmGluR1. These results indicate that MPEP and CPCCOEt bind to overlapping binding pockets in the TM region of group I mGluRs but interact with different non-conserved residues.

CPCCOEt, a noncompetitive metabotropic glutamate receptor 1 antagonist, inhibits receptor signaling without affecting glutamate binding.

Metabotropic glutamate receptors (mGluRs) are a family of G protein-coupled receptors characterized by a large, extracellular N-terminal domain comprising the glutamate-binding site. In the current study, we examined the pharmacological profile and site of action of the non-amino-acid antagonist 7-hydroxyiminocyclopropan[b]chromen-1a-carboxylic acid ethyl ester (CPCCOEt). CPCCOEt selectively inhibited glutamate-induced increases in intracellular calcium at human mGluR1b (hmGluR1b) with an apparent IC50 of 6.5 microM while having no agonist or antagonist activity at hmGluR2, -4a, -5a, -7b, and -8a up to 100 microM. Schild analysis indicated that CPCCOEt acts in a noncompetitive manner by decreasing the efficacy of glutamate-stimulated phosphoinositide hydrolysis without affecting the EC50 value or Hill coefficient of glutamate. Similarly, CPCCOEt did not displace [3H]glutamate binding to membranes prepared from mGluR1a-expressing cells. To elucidate the site of action, we systematically exchanged segments and single amino acids between hmGluR1b and the related subtype, hmGluR5a. Substitution of Thr815 and Ala818, located at the extracellular surface of transmembrane segment VII, with the homologous amino acids of hmGluR5a eliminated CPCCOEt inhibition of hmGluR1b. In contrast, introduction of Thr815 and Ala818 at the homologous positions of hmGluR5a conferred complete inhibition by CPCCOEt (IC50 = 6.6 microM), i.e., a gain of function. These data suggest that CPCCOEt represents a novel class of G protein-coupled receptor antagonists inhibiting receptor signaling without affecting ligand binding. We propose that the interaction of CPCCOEt with Thr815 and Ala818 of mGluR1 disrupts receptor activation by inhibiting an intramolecular interaction between the agonist-bound extracellular domain and the transmembrane domain.