A Phase II Randomized Study of the Virologic and Immunologic Effects of d4T vs Zidovudine Plus d4T vs Zidovudine Plus Ddl in HIV-Infected Patients With CD4 Cell Counts Between 300-600/mm3 and Greater Than 12 Weeks Zidovudine Experience

Inclusion Criteria Concurrent Medication: Required for patients whose CD4 count falls below 200 cells/mm3: PCP prophylaxis with TMP/SMX, aerosolized pentamidine, or dapsone. Allowed: Atovaquone, IV pentamidine, trimethoprim-dapsone, clindamycin-primaquine, trimetrexate, or TMP/SMX for acute PCP. Topical antifungals, clotrimazole, ketoconazole, fluconazole, and amphotericin B for mucosal and esophageal candidiasis. Itraconazole. Amphotericin B. Rifabutin. Isoniazid. Pyrazinamide. Clofazimine. Clarithromycin. Azithromycin. Ethambutol. Amikacin. Ciprofloxacin. Ofloxacin. Pyrimethamine. Sulfadiazine. Clindamycin. Ganciclovir. G-CSF. Acyclovir (up to 1000 mg/day). Erythropoietin. Antibiotics for bacterial infections. Antipyretics. Analgesics. Antiemetics. Rifampin. Concurrent Treatment: Allowed: Local radiation therapy. Patients must have: HIV infection. CD4 count 300-600 cells/mm3. More than 12 weeks (was 24 weeks, AMENDED 3/31/96) of total prior AZT ( > 500 mg/day without serious adverse event). Subjects must be actively taking ZDV for at least 4 continuous weeks up to the time of study entry. No prior or current history of AIDS. No active opportunistic infection. Life expectancy of at least 2 years. Consent of patient and parent or guardian if less than 18 years of age. NOTE: Protocol is approved for prisoner enrollment. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: Malignancy requiring systemic cytotoxic chemotherapy. Serious underlying medical condition other than HIV that would reduce life expectancy to < 2 years. Concurrent Medication: Excluded: Antiretrovirals other than study drugs. Foscarnet. Patients with the following prior conditions are excluded: Unexplained temperature >= 38.5 C for 7 days or chronic diarrhea (>= three stools daily) for 15 days, if occurring within 30 days prior to study entry. History of acute or chronic pancreatitis. History of grade 2 or higher peripheral neuropathy. History of grade 3 or worse intolerance to 500-600 mg/day AZT. Prior Medication: Excluded: (within 30 days prior to study entry) Prior ddI, ddC, 3TC or d4T (more than 2 weeks total). Non-nucleoside reverse transcriptase inhibitor or protease inhibitor. Biologic response modifiers such as interferon and IL-2. Other experimental therapy.