Maintenance therapy for cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome: foscarnet

High-dose (2000-microgram) intravitreous ganciclovir in the treatment of cytomegalovirus retinitis

OBJECTIVE

The authors prospectively studied visual outcome, relapse, complications, and survival of patients with acquired immune deficiency syndrome (AIDS)-related cytomegalovirus (CMV) treated with high-dose intravitreous ganciclovir (2 mg/0.1 ml) injections. The outcomes were compared with those of patients treated with standard doses of intravenous ganciclovir in the same institution. The histopathologic and electrophysiologic effects of high-dose intravitreous ganciclovir injections in rabbits also were studied.

DESIGN

A nonrandomized case series.

PARTICIPANTS

A total of 42 patients (74 eyes) were treated with intravitreous injections and 18 patients (27 eyes) were treated with intravenous ganciclovir. Five eyes of three New Zealand white rabbits were injected with ganciclovir, and the sixth eye was a control specimen.

INTERVENTION

Patients treated with intravitreous injections received twice-weekly doses of 2 mg/0.1 ml ganciclovir for 3 weeks, then weekly injections. Patients treated with intravenous ganciclovir received standard doses. Patients were monitored with regular examinations. Rabbit eyes were given intravitreous injections of 1 mg/0.1 ml of ganciclovir weekly for 4 weeks.

MAIN OUTCOME MEASURES

Assessments of vision, retinal inflammation, and survival were made. Electroretinograms were performed on the rabbit eyes, and they were processed for light and electron microscopy.

RESULTS

In the intravitreous group, visual acuity (VA) was stable in 64 of 74 eyes, 5 improved, and 5 deteriorated. Sixty-three (85%) of 74 eyes had final VA of 20/20 to 20/40. Relapse occurred in five eyes (7%; median time, 42 weeks). There were three cases of endophthalmitis. Median survival after diagnosis of CMV retinitis was 36 weeks. In the intravenous group, VA was stable in 18 eyes, 0 improved, and 9 deteriorated. Sixteen (59%) of 27 eyes had final VA of 20/20 to 20/40. Relapse occurred in 15 eyes (56%) at a median time of 21 weeks. Median survival was 21 weeks. The rabbit studies showed no evidence of toxicity.

CONCLUSION

High-dose intravitreous ganciclovir effectively suppressed CMV retinitis, preserved vision, and prevented relapse without deterioration in survival.

Cytomegalovirus infection in acquired immune-deficiency syndrome

Cytomegalovirus (CMV) infection is very common in acquired immune deficiency syndrome (AIDS) with approximately 40% of patients presenting CMV visceral involvement at advanced stage disease. The most common localizations are retinitis and gastrointestinal involvement; central nervous system disorders are likely to be underestimated. Diagnosis of CMV disease should be assessed, for all localizations except retinitis, on the association of clinical symptoms with presence of CMV inclusions in biopsy specimens. Two drugs, ganciclovir and foscarnet, are currently licensed for treatment. Both are administered intravenously. Since progression of CMV disease is very common particularly in retinitis, maintenance therapy should be given throughout remaining life. Unfortunately, maintenance therapy does not entirely prevent the risk of relapses. Drug toxicity is mainly bone marrow suppression with ganciclovir and renal insufficiency with foscarnet. Since quality of life is severely impaired by long-term daily intravenous treatment, orally active drugs are urgently needed both for treatment and primary prophylaxis of CMV infection.

Pharmacokinetics of concomitantly administered foscarnet and zidovudine for treatment of human immunodeficiency virus infection (AIDS Clinical Trials Group protocol 053)

Foscarnet and zidovudine (ZDV) pharmacokinetic parameters were not altered in five patients receiving 14 days of concomitant therapy. Foscarnet clearance in plasma averaged (+/- standard deviation) 0.16 +/- 0.03 and 0.13 +/- 0.05 liter/h/kg of body weight in the absence and presence of ZDV. ZDV parameters were also not significantly altered, with a mean (+/- standard deviation) oral clearance of 2.7 +/- 1.0 and 2.6 +/- 0.8 liter/h/kg for the 2 study days, respectively.