Inclusion Criteria

Concurrent Medication:

Allowed:

• Ganciclovir.

Exclusion Criteria

Co-existing Condition:

Patients with the following are excluded:

• Known allergy to foscarnet.
• Any clinically significant pulmonary or neurologic impairment (e.g., patients who are intubated or comatose).
• Corneal, lens, or vitreous opacification which precludes examination of the fundi in patients with cytomegalovirus (CMV) retinitis.

Concurrent Medication:

Excluded:

• Acyclovir.
• Nephrotoxic agent.

Patients with the following are excluded:

• Known allergy to foscarnet.
• Any clinically significant pulmonary or neurologic impairment (e.g., patients who are intubated or comatose).
• Corneal, lens, or vitreous opacification which precludes examination of the fundi in patients with CMV retinitis.

Prior Medication:

Excluded within 7 days of study entry:

• Immunomodulators.
• Biologic response modifiers.
• Investigational agents.

AIDS patients experiencing cytomegalovirus (CMV) retinitis may be enrolled if they meet one of the following criteria:

• Myelosuppression:
• Previously suffered severe dose-limiting ganciclovir-related myelosuppression, or are ineligible for ganciclovir treatment due to myelosuppression.
• Ganciclovir treatment failure:
• Clearly failed to have a therapeutic response to ganciclovir therapy.
• Patients must be able to give informed consent.
• Patients presenting with a baseline absolute neutrophil count < 750 cells/mm3 or baseline platelet count < 50000 platelets/mm3 will be categorized as ineligible to receive ganciclovir induction therapy and will be allowed to enter the study.

• Patients who enter the study because of ganciclovir toxicity will have received ganciclovir therapy which resulted in either absolute neutrophil count falling to < 750 cells/mm3 or platelet count falling to < 50000 platelets/mm3 on two separate occasions during either

  1) a ganciclovir induction regimen of 7.5 mg or less ganciclovir/kg/day in divided doses or 2) a maintenance regimen of 5 mg or less ganciclovir/kg/day as a single dose.

• Patients who enter the study because of ganciclovir treatment failure will meet one of the following criteria:

• 1) CMV retinitis progression as defined in section V.C.1., i.e., has occurred either at the end of a 10 - 21 day induction course of ganciclovir (7.5 - 10.0 mg/kg/day in divided doses) or 2) during the first 28 days of maintenance ganciclovir therapy (5 or more mg/kg/day in at least 5 days/week) where maintenance therapy began within

  1. week of completing induction therapy.