A Phase II Double-Blind Study of Two Doses of SC-49483 in Combination With Zidovudine (ZDV) Versus ZDV

Inclusion Criteria Concurrent Medication: Required: * PCP prophylaxis (trimethoprim/sulfamethoxazole, dapsone, or aerosolized pentamidine) in patients with CD4 count \<= 200 cells/mm3. Allowed: * Topical antifungal agents, ketoconazole, fluconazole, and itraconazole for candidiasis or disseminated fungal infections, as medically indicated. * Maintenance therapy for Mycobacteria disease with isoniazid, ethambutol, rifampin, pyrazinamide, clofazimine, ciprofloxacin, clarithromycin, or rifabutin. * Maintenance therapy for toxoplasmosis with pyrimethamine, sulfadiazine, or clindamycin. * Maintenance therapy for herpes simplex virus with acyclovir at \<= 1000 mg/day. * Recombinant erythropoietin and G-CSF, if indicated. * Antibiotics for bacterial infections. * Symptomatic treatment such as antipyretics, analgesics, nonsteroidal anti-inflammatory agents, and antiemetics. Concurrent Treatment: Allowed: * Localized radiation therapy and limited intralesional therapy for cutaneous Kaposi's sarcoma. Patients must have: * Documented HIV infection. * Per 07/19/94 amendment, one of the following: * CD4 count 150 - 350 cells/mm3 within 60 days prior to study entry AND prior AZT for no more than 12 months cumulative (given with or without ddI or ddC). * CD4 count 50 - 350 cells/mm3 within 60 days prior to study entry AND no prior antiretroviral therapy. * MT-2 cell assay within 60 days prior to study entry. NOTE: * Minimal Kaposi's sarcoma is permitted. Exclusion Criteria Co-existing Condition: Patients with the following condition are excluded: * Malignancy other than minimal Kaposi's sarcoma. Concurrent Medication: Excluded: * Antiretroviral therapies (other than study drug). * Biologic response modifiers. * Systemic corticosteroids for \> 21 consecutive days. * Foscarnet. * Systemic cytotoxic chemotherapy for a malignancy. Patients with the following prior conditions are excluded: * History of cataracts. * History of intolerance to AZT at \<= 600 mg/day. * Unexplained temperature \>= 38.5 degrees C that persists for any 7 days within the 30 days prior to study entry. * Chronic diarrhea (defined as \>= 3 stools per day) that persists for any 15 days within the 30 days prior to study entry. Prior Medication: Excluded: * More than 6 months (more than 12 months per 07/19/94 amendment) cumulative prior therapy with AZT. * Prior induction or maintenance therapy with foscarnet. * Any investigational drug within 30 days prior to study entry. * Prior SC-49483 or SC-48334. * Prior ddC, ddI, or stavudine (d4T) as monotherapy. * Interferon or interleukin within 30 days prior to study entry. * Prior non-nucleoside reverse transcriptase inhibitors (e.g., NVP, ATV). * Systemic corticosteroids for \> 21 consecutive days. * Acute treatment for a serious infection or any opportunistic infection within 14 days prior to study entry. * Prior combination therapy with AZT, ddI, and/or ddC within 30 days prior to study entry.