Inclusion Criteria

Concurrent Medication:

Allowed:

• Corticosteroids for treatment of lymphocytic interstitial pneumonitis.

Concurrent Treatment:

Allowed:

• Intravenous hyperalimentation.

Patients must have the following:

• P-2 class symptomatic HIV infection as defined by CDC OR who are asymptomatic but whose total CD4 cell count is < 500 cells/mm3.
• Freedom from significant active opportunistic or other infection requiring specific therapy.

Part B patients:

• Prior treatment with zidovudine (AZT) that was discontinued because of hematologic toxicity.
• Availability of a parent or legal guardian who is sufficiently reliable to give informed consent and follow necessary study procedures including administration of medications and return for follow-up visits.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• Critically ill, clinically unstable, or receiving drug therapy for an opportunistic or other infection.
• History of acute or chronic pancreatitis.

Patients with the following are excluded:

• Critically ill, clinically unstable, or receiving drug therapy for an opportunistic or other infection.
• History of acute or chronic pancreatitis.

Prior Medication:

Excluded:

• Antiretroviral or other antiviral agent within 14 days of entry into study.
• Immunomodulating agents, cytolytic chemotherapeutic agents, corticosteroids within 30 days (except for lymphocytic interstitial pneumonitis).

Part A patients:

• Zidovudine (AZT) or didanosine (ddI).

Part B patients:

• Didanosine (ddI).

Prior Treatment:

Excluded:

• Radiation therapy within 30 days.
• Intravenous immunoglobulin preparations within 14 days of entry into study.