Important note: Information in this article was accurate in 1995. The state of the art may have changed since the publication date.
 |
GMHC Treatment Issues - Vol. 9, No. 12 - December 1995
3TC/AZT is widely considered the best of all available nucleoside analog combinations. It is certainly the newest combination, but, as the accompanying graph illustrates, the boost in CD4 cell counts from AZT/3TC is not significantly different than from ddI/AZT. (The graph gives a tentative comparison by superimposing the data reported from Glaxo's NUCA 3001 trial of 3TC plus AZT with data from the ACTG 175 trial. Patients in both studies had similar CD4 cell counts at baseline (about 350) and no prior anti-HIV treatment.)
One reason why 3TC/AZT is considered superior is the laboratory finding that the genetic mutation in HIV giving rise to 3TC resistance also counteracts the mutations that confer resistance to AZT. It is thought that HIV cannot be resistant simultaneously to both drugs.
An analysis by Victoria Johnson, M.D., of drug resistance in the North American AZT-experienced 3TC study (NUCA 3002) found that dual resistance to AZT and 3TC does indeed take place. Of seven HIV trial participants showing evidence of high-level resistance to 3TC at week twelve, five were strongly resistant to both drugs at week twelve and four were resensitized to AZT by week twelve.
Another eighteen trial participants were not resistant to AZT in the first place, and so could receive none of the presumed benefits of 3TC resistance. Six people checked by the investigators were still not resistant to 3TC at week twelve. Probably most continued to have virus sensitive to both drugs.
The moral of our story is: Observe what is happening in the human body rather than relying on simple laboratory findings.
951201
GM091203
Copyright © 1995 - Treatment Issues. Reproduced with permission. Treatment Issues is published twelve times yearly by GMHC, Inc. All rights reserved. Noncommercial reproduction is encouraged. Subscription lists are kept confidential. GMHC Treatment Issues, The Tisch Building, 119 West 24th Street, New York, NY 10011 fredg@gmhc.org http://www.gmhc.org
AEGiS is made possible through unrestricted grants from Boehringer Ingelheim, Elton John AIDS Foundation, iMetrikus, Inc., John M. Lloyd Foundation, the National Library of Medicine, and donations from users like you. Always watch for outdated information. This article first appeared in 2003. This material is designed to support, not replace, the relationship that exists between you and your doctor.
AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.
Copyright ©1980, 2003. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content. .