A Multicenter Dose Ranging Clinical Trial of 2',3'-Dideoxycytidine in the Treatment of Patients With AIDS and Advanced ARC.

Inclusion Criteria Concurrent Medication: Allowed: * Aspirin, acetaminophen, and nonsteroidal anti-inflammatory agents. * Acute therapy (7 days) with oral acyclovir. * Acute therapy with ketoconazole. Exclusion Criteria Co-existing Condition: Patients with the following are excluded: * Negative antigen test within 2 weeks of starting therapy. * Significant malabsorption (\> 10 percent weight loss within past 3 months with serum carotene \< 75 IU/ml or vitamin A \< 75 IU/ml). * Significant cardiac, liver, or neurologic disease. * For group A: * Opportunistic infection or malignancy fulfilling definition of AIDS, or with concurrent neoplasm other than basal cell carcinoma of the skin or in situ carcinoma of the cervix. * For group B: * Active opportunistic infection, symptomatic visceral Kaposi's sarcoma (KS), progression of KS within the month prior to study entry, or with concurrent neoplasms other than KS, basal cell carcinoma of the skin, or in situ carcinoma of the cervix. Concurrent Medication: Excluded: * Acyclovir therapy. * Chemoprophylaxis for Pneumocystis carinii pneumonia. * Other antiretroviral agents, biologic modifiers, or systemic corticosteroids. * Other experimental medications, sedatives, and barbiturates. * Group B: * Therapy and/or prophylaxis for AIDS-defining opportunistic infection, antineoplastic therapy. Concurrent Treatment: Excluded: \- Transfusion dependency (requiring 2 units of blood more than once per month). Patients with history of idiopathic thrombocytopenia purpura are excluded. Prior Medication: Excluded within 30 days of study entry: * Biologic modifiers or corticosteroids. * Excluded within 90 days of study entry: * Antiretroviral agents. Prior Treatment: Excluded within 2 weeks of study entry: * Transfusion. Inclusion criteria are: * Consistently positive HIV antigen as defined by Abbott HIV antigen test. This demonstration will be seen on two occasions, each separated by at least 72 hours, the last of which must be within 2 weeks of starting therapy. * HIV antigen titer must be = or \> 100 pg. * Positive antibody to HIV confirmed by any federally licensed enzyme-linked immunosorbent assay (ELISA) test kit. The following conditions are allowed: \- Basal cell carcinoma of the skin or in situ carcinoma of the cervix. Active substance abuse.