Important note: Information in this article was accurate in June 2001. The state of the art may have changed since the publication date.AIDSWEEKLY Plus; Monday, June 11, 2001
Michael Greer, Staff Medical Writer
NewsRx - Some protease inhibitors are much more likely to induce HIV susceptibility to their cousins after unsuccessful use, according to AIDS researchers in California.
C.A. Kemper and colleagues at the Santa Clara Valley Medical Center in San Jose investigated the "pattern of HIV 1 susceptibility to protease inhibitors in patients failing an initial protease inhibitor-containing regimen." The results of their study were published in the journal AIDS.
Of the five protease inhibitors examined, Kemper and coworkers found that nelfinavir was the least likely to cause cross-tolerance to other drugs in patients with persistently high viral loads.
The chance of developing reduced viral sensitivity to other protease inhibitors was significantly reduced in patients unsuccessfully treated with nelfinavir compared with those failing indinavir (P<0.007), amprenavir, saquinavir, or ritonavir therapy (P<0.001), the researchers reported. Cross-tolerance risks were similar after taking prior protease inhibitor use into account.
Resistance to amprenavir or saquinavir was the least common, occurring with significantly lower frequency than resistance to other protease inhibitors. Tolerance to a drug was defined as a greater than 2.5-fold rise in the 50% inhibitory concentration (IC50) of that drug, Kemper and team said.
While 18% of the patients studied had viral populations sensitive to all protease inhibitors, 8% had developed resistance to all such drugs ("Sequencing of protease inhibitor therapy: Insights from an analysis of HIV phenotypic resistance in patients failing protease inhibitors," AIDS 2001 Mar 30;15(5):609-15.
"The frequency of protease inhibitor cross-resistance and the magnitude of changes in susceptibility varied according to the initial protease inhibitor used in the failing treatment regimen," Kemper and colleagues concluded. "Significantly less protease inhibitor cross-resistance was demonstrated for isolates from patients failing a nelfinavir-containing regimen compared with those from patients receiving other protease inhibitors."
The corresponding author for this report is C.A. Kemper, Santa Clara Valley Medical Center, Dept. of Medicine, Infectious Diseases Division, 751 S. Bascom Avenue, San Jose, CA 95128, USA.
A search at www.NewsRx.net using the search term "AIDS and HIV therapy" yielded 1,191 articles in six specialized reports.
Key points reported in this study include:
This article was prepared by AIDS Weekly editors from staff and other reports.
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