A Randomized, Double-Blind, Four-Arm Study Comparing Combination Nucleoside, Alternating Nucleoside, and Triple-Drug Therapy for the Treatment of Advanced HIV Disease (CD4 <= 50/mm3)

Inclusion Criteria Concurrent Medication: Required: PCP prophylaxis. Allowed: Erythropoietin maintenance. G-CSF and GM-CSF. Prophylaxis for Mycobacterium avium intracellulare. Antifungal prophylaxis or treatment with specific drugs. Maintenance therapy for opportunistic infection. Over-the-counter medications or alternative therapies such as vitamins and herbs. Antibiotics as clinically indicated. Steroids for < 21 days for acute problems. Antipyretics, analgesics, allergy medication, antidepressants, sleep medications, oral contraceptives, or other appropriate medications. Concurrent Treatment: Allowed: Radiation therapy for cutaneous Kaposi's sarcoma. Acupuncture. Patients must have: Documented HIV infection. CD4 count <= 50 cells/mm3. Either no prior nucleoside therapy OR a history of prior nucleoside therapy in the absence of high-grade intolerance. Life expectancy of at least 6 months. Consent of parent or guardian if < 18 years of age. Normal chest x-ray at baseline or within 6 months prior to study entry in the absence of new pulmonary or cardiac symptoms (per 12/28/94 amendment). NOTE: Patients who withdrew from protocol ACTG 193 therapy prior to activation of ACTG 193A are not eligible. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: Abnormal baseline chest x-ray. New pulmonary or cardiac symptoms. Psychological or emotional problems sufficient to prevent compliance with study medication. Concurrent Medication: Excluded: Systemic chemotherapy for malignancy. Acute or induction therapy for opportunistic infection. Antiretroviral drugs other than study drugs. Biological response modifiers. Erythromycin, phenytoin, phenobarbital, warfarin, or coumadin. Patients with the following prior conditions are excluded: History of recurrent grade 3 or greater toxicity to AZT, ddI, or ddC on two or more occasions. Evidence of active pulmonary disease within 6 months prior to study entry. History of grade 3 or worse peripheral neuropathy. History of acute or chronic pancreatitis. Prior Medication: Excluded: Prior nevirapine. Excluded within 7 days prior to study entry: Acute therapy for opportunistic infection (maintenance therapy is permitted). Acute systemic therapy for a nonopportunistic infection or other medical condition. Antiretroviral drugs other than AZT, ddI, or ddC. Biological response modifiers. d4T therapy. Nucleosides other than those used in the study. Antibiotics containing clavulanate potassium. Prior Treatment: Excluded: More than 4 units of blood in a 30-day period. Active alcohol or drug abuse.