Inclusion Criteria

Concurrent Medication:

Allowed:

Medication necessary for the patient's welfare at the discretion of the investigator.

Patients must have the following:

• Received zidovudine (AZT) 200 mg every 4 hours (q4h) continuously for 8 - 16 weeks without Grade 3 or higher toxicity.
• Detectable p24 antigen in serum on at least 2 occasions during the prestudy period. All serum p24 antigen concentrations measured during the prestudy period must be at least twice the concentration cutoff value of the assay.
• Capability of giving informed consent.
• Per amendment of 890721, patients must enter the study period by September 30, 1989.

Exclusion Criteria

Co-existing Condition:

Patients with the following will be excluded:

• A history of hypersensitivity reaction to foscarnet or zidovudine (AZT).
• History of Grade 3 or 4 toxicity with AZT.
• Current Grade 2 or higher AZT toxicity.
• Osteomalacia, neoplasm metastatic to bone, or other known bone disease.
• Active opportunistic infection requiring myelosuppressive or nephrotoxic therapy.

Concurrent Medication:

Excluded:

• Antimetabolites.
• Immunomodulators.
• Nephrotoxins.
• Antiviral therapy.
• Myelosuppressive or nephrotoxic therapy.
• Acetaminophen.

Patients with the following will be excluded:

• A history of hypersensitivity reaction to foscarnet or zidovudine (AZT).
• History of Grade 3 or 4 toxicity with AZT.
• Current Grade 2 or higher AZT toxicity.
• Osteomalacia, neoplasm metastatic to bone, or other known bone disease.
• Active opportunistic infection requiring myelosuppressive or nephrotoxic therapy.