Studies have indicated that maintenance therapy with AZT over extended periods may be limited by dose-dependent toxicity, primarily myelosuppression, and by the emergence of drug-resistant HIV strains. It is anticipated that the combination of AZT with either ddI or ddC may promote higher antiviral efficacy, with acceptable toxicity and less likelihood of development of drug-resistant strains, than AZT alone.
Approximately 1200 patients are randomized in a 2:1:1:2 ratio to one of the following four treatment arms: AZT plus ddI, AZT plus ddI placebo, AZT plus ddC placebo, and AZT plus ddC. Average follow-up is 2 years.
