Phase III Randomized Double-Blind Placebo Controlled Study To Evaluate the Safety and Efficacy of Betaseron in AIDS and Advanced ARC Patients Receiving a Reduced-Dose AZT Regimen

Inclusion Criteria Concurrent Medication: Allowed: * Zidovudine (AZT). Patient must have: * Uninterrupted therapy with reduced-dose AZT 500 - 600 mg/day for at least 3 weeks before entry. * Acceptable hepatic and renal function. * AMENDED to delete the following sentence: * Hematologic intolerance to full-dose zidovudine (AZT) (1000 - 1200 mg/day). Exclusion Criteria Co-existing Condition: Patients with the following are excluded: * Concurrent, ineffectively controlled opportunistic infections. * Extensive cutaneous and/or visceral Kaposi's sarcoma requiring systemic chemotherapy. * Proteinuria of 2+ or greater. * HIV encephalopathy. * HIV wasting syndrome. * New York Heart Classification III or IV. * Uncontrolled angina pectoris. * Evidence of clinically significant, multifocal uncontrolled cardiac dysrhythmias. Concurrent Medication: Excluded: * Antiretrovirals other than zidovudine (AZT) or Betaseron. * Chronic acyclovir therapy. * Acetaminophen. Patients with the following are excluded: * Intolerance (hematologic or otherwise) to zidovudine (AZT) at a dose of 100 mg orally every 4 hours. AMENDED to: * Intolerance at a dose of 500 to 600 mg/day. * Medical or psychiatric conditions that compromise the patient's ability to give informed consent or complete the study. Prior Medication: Excluded within 30 days of study entry: * Cytotoxic chemotherapy. * Prior therapy with alpha, beta, or gamma interferons. Active drug or alcohol abuse.