To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: ROI CONFERENCE: Drug-Resistant Strains Of HIV May Have Sensitivity To Abacavir URL: http://www.pslgroup.com/dg/58276.htm Doctor's Guide February 5, 1998
CHICAGO, IL -- February 5, 1998 -- Data from preliminary laboratory studies show that some strains of HIV which have mutated over long-term anti-HIV drug treatment to avoid the effects of the marketed nucleoside analogue reverse transcriptase inhibitors (AZT, 3TC, d4T, ddI, ddC), are still sensitive to the effects of Glaxo Wellcome's investigational anti-HIV drug abacavir. The results were presented at the Fifth Conference on Retroviruses and Opportunistic Infections, held in Chicago. Utilising a new in vitro laboratory test known as the Antivirogram(TM), researchers from Belgium-based Virco Inc. screened approximately 1,000 virus samples from treatment experienced HIV patients to evaluate the susceptibility of those samples to abacavir. This analysis showed that the vast majority of isolates that were resistant to one or two of the available nucleoside analogues remained sensitive to abacavir. However, samples that were resistant to three or more nucleoside analogues were less sensitive to abacavir. The Antivirogram, referred to as a phenotypic resistance test, measures the susceptibility of a particular virus strain to a particular drug. This is done by determining the amount of that drug that is required to prevent 50 percent of the replication of that virus strain in a test tube. These sensitivity results are expressed as IC50 values, or the inhibitory concentrations of a drug necessary to prevent 50 percent of replication of the specific virus strain being studied. In a second study, results from a phase II trial of abacavir showed that many patients who have been treated with AZT, 3TC, d4T or ddI will respond to treatment with abacavir. Also, that phenotypic viral resistance, or the susceptibility of a patient's virus to abacavir at baseline, was found to correlate with the type of viral load response as a result of treatment with abacavir. "There is still a lot of work that needs to be done to validate the relevance of resistance testing to clinical outcomes for all antiretrovirals," said Randall Lanier, Ph.D., a virologist at Glaxo Wellcome Inc. "However, these data indicate that abacavir may be clinically useful in many patients who have received prior therapies and may harbour virus that is resistant to nucleoside analogues." Abacavir is a nucleoside analogue reverse transcriptase inhibitor and is in phase III clinical development as a treatment for HIV and AIDS. In early clinical trials, data have suggested that abacavir has antiviral potency often associated with protease inhibitors, and is effective in combinations with other nucleoside analogues, protease inhibitors and non-nucleosides. In clinical trials to date, involving more than 3,000 patients, abacavir has been generally well-tolerated with most commonly reported adverse events including headache, nausea, vomiting, malaise and rash. In two to three percent of patients receiving abacavir, a hypersensitivity reaction has been observed which is characterised by fever plus any one or all of the following: nausea (with or without vomiting), malaise and possibly an accompanying rash. These symptoms have been observed from several days to four weeks after initiating therapy and resolve within one to two days following discontinuation of abacavir. However, patients experiencing this reaction must not resume treatment with abacavir because rare cases of a life-threatening, and in one case fatal, hypersensitivity reaction have been observed in patients who have resumed treatment after experiencing the initial hypersensitivity reaction. More information on: AZT, Glaxo Wellcome --------------------------------------------------------------------------------------------- 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.