To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: ACCP: Anti-Parasitic Drug Found Safe For Humans URL: http://www.pslgroup.com/dg/23B87A.htm Doctor's Guide October 6, 2003
By Mike Fillon TAMPA, FL -- October 6, 2003 -- In the first human trial, the anti-parasitic moxidectin, also known as MOX, was shown to be safe at varying dosage levels. Results of the study were presented on September 21st at the 32nd Annual Meeting of the American College of Clinical Pharmacology (ACCP). "MOX is a well-known veterinary parasite control drug," said researcher Monette M. Cotreau. "It affects the nervous system of parasites, leading to their death, but is considered non-toxic to mammals." MOX is primarily used to prevent heartworm infection and for the treatment of internal and external parasites in cattle, sheep, deer and horses. In humans, MOX is currently under development for the treatment of onchocerciasis, or river blindness, a parasitic disease caused by the prelarval (microfilaria) and adult stages of the nematode Onchocerca volvulus. The disease is transmitted by the bite of certain species of female Simulium flies, or black flies, that bite by day and are found near rapidly flowing rivers and streams. Onchocerciasis is endemic in more than 25 nations located in a broad band across the central part of Africa. Small endemic foci are also present in the Arabian Peninsula (Yemen) and in the Americas (Brazil, Colombia, Ecuador, Guatemala, southern Mexico and Venezuela).
In the study, the researchers hoped to determine the safety, tolerability and pharmacokinetics of a single dose of MOX in humans. The influence of food on the pharmacokinetics of MOX was also evaluated at two doses -- 9 mg and 36 mg.
The subjects included seven cohorts of six each, with one subject in each group receiving a placebo. Five of the cohorts fasted and were administered single dosages of 3 mg, 9 mg, 18 mg, 36 mg and 54 mg. The two fed cohorts were administered single dosages of 9 mg and 36 mg.
All subjects were between the ages of 18 and 45 years, with normal cardiac, haematologic, hepatic and renal function. Safety and tolerability were assessed by physical exams, ongoing evaluation of adverse events, and measurement of lab values. Blood samples were collected just prior to dosing and at 1, 2, 4, 8, 12, 24, 36 and 48 hours, and 4, 6, 8, 12, 24, 36, 48, 60 and 80 days after administration.
MOX was generally safe and well tolerated in all groups. Central nervous system side effects tended to be slightly more common in those who received the higher doses of the drug, compared with placebo, but these events were transient and only mild to moderate.
The pharmacokinetics of MOX were dose proportional, and the elimination half-life was found to be quite long: a mean of 20.2 to 35.1 days. A high fat breakfast delayed and increased overall absorption of MOX when taken at both doses of 9 and 36 mg, but maximal concentrations remained similar to those seen when the drug was taken in the fasting state.
Ms. Cotreau said the exact mechanism of the antiparisitic action of MOX is still under investigation, although the activity is thought to result from binding to glutamate-gated chloride channels and the gamma-aminobutyric acid A (GABA A) receptor complex of the parasite. [Study title: The Antiparasitic Moxidectin: Safety, Tolerability, and Pharmacokinetics in Humans.] --------------------------------------------------------------------------------------------- Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. P\S\L shall not be liable for any errors, omissions or delays in this content or any other content on its sites, newsletters or other publications, nor for any decisions or actions taken in reliance on such content. --------------------------------------------------------------------------------------------- This news story was printed from *Doctor's Guide to the Internet* located at http://www.docguide.com --------------------------------------------------------------------------------------- Return to News Story Page This site is maintained by webmaster@pslgroup.com Please contact us with any comments, problems or bugs. All contents Copyright (c) 1998 P\S\L Consulting Group Inc. All rights reserved.