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(BETA) News Briefs: Hydroxyurea plus AZT or ddI


Two Italian studies that will enroll 100 asymptomatic HIV positive individuals with CD4 counts between 300 and 500 are exploring the combination of hydroxyurea (500 mg twice daily) plus AZT (250 mg twice daily) or plus ddI (200 mg twice daily). In the U.S., the government-sponsored AIDS Clinical Trials Group (ACTG) this fall will start a study of hydroxyurea plus ddI. In vitro studies show that anti-HIV activity is enhanced without obvious increased toxicity when hydroxyurea is used in combination with ddI (Science 266: 801-806. 1994).

Hydroxyurea does not act directly against HIV, but rather depletes cells of deoxynucleoside triphosphates (dNTP), which are crucial components (building blocks) of DNA synthesis. "When HIV enters a cell depleted of dNTP by the action of hydroxyurea, there is not enough of the building blocks present for the virus to survive," explains Franco Lori, MD, of the research Institute for Genetic and Human Therapy in Pavia, Italy. In combination with ddI, Lori says, hydroxyurea decreases viral replication so dramatically that there's less virus available to mutate, possibly delaying the onset of resistance to ddI.

"Hydroxyurea may permit a significant reduction in the toxicity of ddI, since we would like to combine the 2 drugs at low doses," says Lawrence Fox, MD, of the National Institute of Allergy and Infectious Diseases (NIAID). Fox says he is skeptical about hydroxyurea in combination with AZT because both agents cause bone marrow toxicity. A controlled, triple combination study of hydroxyurea plus ddI plus d4T is scheduled to start in August, sponsored by the Shared Medical Research Foundation of Tarzana, California. See also page 71 of the March 1995 issue of BETA.


Copyright © 1995 -BETA, Publisher. All rights reserved to the San Francisco AIDS Foundation. Reproduced by permission. Reproduction of this article (other than one copy for personal reference) must be cleared through BETA: PO Box 426182, San Francisco, CA 94142-6182. Tel: 415 487 8060 Fax: 415 487 8069 San Francisco AIDS Foundation, Mail SFAF..

Information in this article was accurate in September 1, 1995. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.