The study has been extended to offer 52 weeks of maintenance therapy after the 10 weeks of the placebo controlled period are concluded successfully.

Inclusion Criteria

Concurrent Medication:

Allowed:

• Zidovudine (AZT).

Patients must have:

• Diagnosis of AIDS related complex (ARC).
• Given written informed consent.
• Been receiving a dose of = or < 600 mg/day of zidovudine (AZT) at least 90 days prior to study entry IF they are currently taking AZT.

Prior Medication:

Allowed:

• Zidovudine (AZT) at a dose = or < 600 mg/day at least 90 days prior to study entry.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• History of AIDS-defining condition or evidence of AIDS dementia.
• Evidence of chronic hepatitis with severe liver dysfunction, or other active gastrointestinal, renal, respiratory, endocrine, hematologic, cardiovascular or psychiatric disorder that would limit the subject's ability to complete the 12 weeks of the study period.

Concurrent Medication:

Excluded:

• Ketoconazole.
• Trimethoprim / sulfamethoxazole (TMP/SMX).
• Experimental medications.

Patients with the following are excluded:

• Absolute CD4 count of < 100 or > 350 cells/mm3.
• Any disease or disorder listed in Patient Exclusion Co-existing Conditions.
• Unlikely or unable to comply with the requirements of the protocol.
• Unwilling or unable to give informed consent.
• Development of antibodies to interferon during prior interferon therapy that occurred > 3 months prior to study entry.

Prior Medication:

Excluded within 45 days of study entry:

• Immunomodulators (e.g., BCG vaccine, isoprinosine).
• Chemotherapy.
• Steroids.
• Excluded within 3 months of study entry:
• Interferon therapy. Active IV drug abuse.