Contrary to expectations, rates of major neurosensory disability have not improved, and academic performance is poorer at early school age in 2005 than in earlier eras for EP children born in the state of Victoria, Australia.
Liver X-receptor (LXR) agonists have been postulated to enhance reverse cholesterol transport (RCT), a process believed to shuttle cholesterol from the periphery back to the liver. Enhancing RCT via the upregulation of cholesterol transporters such as the adenosine triphosphate-binding cassettes ABCA1 and ABCG1 could therefore inhibit the progression of atherosclerosis. LXR-623 is a synthetic ligand for LXRs alpha and beta that has shown promise in animal models of atherosclerosis. The authors present results from a single ascending-dose study of the safety, pharmacokinetics, and pharmacodynamics of LXR-623 in healthy participants. LXR-623 was absorbed rapidly with peak concentrations (C(max)) achieved at approximately 2 hours. The C(max) and area under the concentration-time curve increased in a dose-proportional manner. The mean terminal disposition half-life was between 41 and 43 hours independently of dose. LXR activation resulted in a dose-dependent increase in ABCA1 and ABCG1 expression. The effect of LXR-623 concentration on ABCA1 and ABCG1 expression was further characterized via a population pharmacokinetic-pharmacodynamic analysis, yielding EC(50) estimates of 526 ng/mL and 729 ng/mL, respectively. Central nervous system-related adverse events were observed at the 2 top doses tested. The pharmacodynamic effects described here are the first demonstration of "target engagement" by an LXR agonist in humans.
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Calcitonin gene-related peptide (CGRP) was first described as a potent vasodilator.• CGRP is also increasingly recognized as a key player in the pathophysiology of migraine, and CGRP receptor antagonists potentially offer a new approach for treating migraine.• A novel pharmacodynamic assay to measure CGRP receptor antagonist activity non-invasively in humans has been developed, which involves measuring the increase in dermal blood flow induced by topical application of capsaicin on the forearm. WHAT THIS STUDY ADDS• This study shows that the novel oral CGRP receptor antagonist, telcagepant, inhibits the increases in dermal blood flow induced by the topical application of capsaicin on the human forearm.• This experimental medicine model may have utility to assist in dose selection for the development of CGRP receptor antagonists. AIMSTo evaluate inhibition of capsaicin-induced increase in dermal blood flow (DBF) following telcagepant (MK-0974), a potent and selective orally bioavailable calcitonin gene-related peptide (CGRP) receptor antagonist being developed for the acute treatment of migraine. METHODSA three-period crossover study in 12 healthy adult men. Each subject received a single oral dose of telcagepant 300 mg, telcagepant 800 mg or placebo at 0 h, followed 0.5 and 3.5 h later by two topical doses of 300 and 1000 mg capsaicin per 20 ml water-ethanol mixture. Capsaicin was applied at two sites on the volar surface of the subjects' left and right forearms. DBF was assessed by laser Doppler perfusion imaging immediately before ('baseline'), and 0.5 h after each capsaicin application at 1 and 4 h. Plasma samples to determine telcagepant concentrations were collected immediately after laser Doppler perfusion imaging. A pharmacodynamic model was developed to explore the relationship between plasma concentration and inhibition of capsaicininduced increase in DBF. RESULTSGeometric mean plasma concentrations after dosing with 300 mg and 800 mg telcagepant were 720 and 1146 nM, respectively, at 1 h, vs. 582 and 2548 nM, respectively, at 4 h. The pharmacodynamic model suggested that the EC90 for telcagepant inhibition of capsaicin-induced increases in DBF was 909 nM. CONCLUSIONSTelcagepant inhibits the increases in DBF induced by the topical application of capsaicin on the human forearm. This experimental medicine model may have utility to assist in dose selection for the development of CGRP receptor antagonists.
Aprepitant is the first NK1 receptor antagonist approved for use with corticosteroids and 5HT3 receptor antagonists to prevent chemotherapy-induced nausea and vomiting (CINV). The effective dose to prevent CINV is a 125-mg capsule on day 1 followed by an 80-mg capsule on days 2 and 3. Study 1 evaluated the bioavailability of the capsules and estimated the effect of food. The mean (95% confidence interval [CI]) bioavailabilities of 125-mg and 80-mg final market composition (FMC) capsules, as assessed by simultaneous administration of stable isotope-labeled intravenous (i.v.) aprepitant (2 mg) and FMC capsules, were 0.59 (0.53, 0.65) and 0.67 (0.62, 0.73), respectively. The geometric mean (90% CI) area under the plasma concentration time curve (AUC) ratios (fed/fasted) were 1.2 (1.10, 1.30) and 1.09 (1.00, 1.18) for the 125-mg and 80-mg capsule, respectively, demonstrating that aprepitant can be administered independently of food. Study 2 defined the pharmacokinetics of aprepitant administered following the 3-day regimen recommended to prevent CINV (125 mg/80 mg/80 mg). Consistent daily plasma exposures of aprepitant were obtained following this regimen, which was generally well tolerated.
The functional and psychological outcome of 43 patients with polyarticular juvenile arthritis was assessed in order to evaluate the impact of disease on their quality of life. Mean disease duration was 19.7 yr (range 10-39 yr), mean age 26.7 yr (range 18-54 yr) with sex ratio 1:3 (male:female). Severe disability was present in 8% of systemic onset, 34% of RF negative (Rh-P), 38% of RF positive (Rh+P) and 86% of extended pauci-articular (ExP) juvenile arthritics-this last high percentage was due to ocular impairment. The Rh+P had more hip (100% of the group) and knee prostheses (31%) compared with Rh-P (77 and 11% respectively). The Rh+P and ExP groups were the most disabled with the highest proportions of patients with currently active disease (85 and 71% respectively). Psychological testing showed that 21% of the patients were clinically depressed and the rate increased (P = 0.06) with the degree of disability. The proportion of patients demonstrating an anxious preoccupation with their disease increased (P = 0.002) with the degree of disability. Despite this, 66% of patients were employed and 38% felt that their arthritis had no effect on their ability to form relationships.
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