A Randomized, Double-Blind, Three-Arm Study Comparing Combination to Monthly Alternating Nucleoside Therapy for the Treatment of Advanced HIV Disease (CD4 <= 50/mm3) With a Prior History of Nucleoside Therapy

Combining two nucleoside drugs has the theoretical advantage of optimal protection against the evolution of resistant strains of HIV. However, one major problem with combination nucleoside therapy in patients with advanced disease is the increased toxicity resulting from such therapy. One approach to minimize toxicity while perhaps retaining some of the benefits of combination therapy is to alternate the two drugs.

Patients are randomized to one of three treatment arms: AZT plus ddI, AZT plus ddC, and AZT alone alternating monthly with ddI. Half of the patients receiving AZT alternating monthly with ddI will start with AZT, while the other half will start with ddI. Treatment continues until death or termination of the study. Patients are followed every 4 weeks. The study will include a subset of patients for whom virologic, pharmacokinetic, and macroneurologic assessments will be made.