To evaluate short-term and long-term safety and efficacy of intravenous cidofovir (HPMPC) for treatment of small peripheral cytomegalovirus (CMV) retinitis lesions. To provide data on the relative safety and efficacy of 2 doses of HPMPC as maintenance regimens.

In Stage 1, up to 30 patients are randomized to either observation with deferral of treatment until the retinitis progresses (observation group), or to intravenous HPMPC at the higher dose for two consecutive weekly induction doses, followed by the lower dose every other week for maintenance. In Stage 2, up to 70 patients are randomized to observation or to HPMPC at the higher dose for two consecutive weekly induction doses followed by either dose every other week for maintenance, for a total of three treatment groups. Concomitant saline hydration and probenecid are administered to patients receiving HPMPC.

Inclusion Criteria

Concurrent Medication:

Allowed:

• Oral trimethoprim/sulfamethoxazole.
• Aerosolized pentamidine.
• Dapsone.
• Fluconazole.
• Ketoconazole.
• Itraconazole.
• Rifabutin.
• Filgrastim (G-CSF).
• Antiretroviral agents.

Patients must have:

• AIDS by CDC criteria.
• CMV retinitis as determined by a SOCA-certified ophthalmologist, with lesion size, location, and severity as specified in the Disease Status field.

Prior Medication:

Allowed:

• Prophylaxis with anti-CMV agents.

Exclusion Criteria

Concurrent Medication:

Excluded:

• Ongoing therapy for CMV disease with ganciclovir, foscarnet, CMV hyperimmune immunoglobulin, or other investigational agents with anti-CMV activity.
• Therapy with nephrotoxic drugs, including amphotericin B, aminoglycoside antibiotics, vidarabine, and intravenous pentamidine.

Patients with the following prior conditions are excluded:

• History of renal disease or renal dialysis.
• History of clinically significant cardiac disease, including symptoms of ischemia, congestive heart failure, or arrhythmia.
• History of clinically significant probenecid allergy.

Prior Medication:

Excluded:

• Prior therapy for CMV disease with ganciclovir, foscarnet, CMV hyperimmune immunoglobulin, or other investigational agents with anti-CMV activity.
• Therapy with nephrotoxic drugs within the past 7 days, including amphotericin B, aminoglycoside antibiotics, vidarabine, and intravenous pentamidine.

Drug or alcohol abuse sufficient to hinder compliance with study.