Foscarnet treatment of cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome.

Ten patients with acquired immunodeficiency syndrome with newly diagnosed cytomegalovirus (CMV) retinitis were treated with an induction regimen of intravenous foscarnet, 60 mg/kg of body weight, administered as a 2-h infusion and repeated every 8 h for 14 days. At the end of induction, 9 of 10 patients had stabilized (no new retinal lesions and stable old lesions [7 patients]) or improved (decreased retinal opacification [2 patients]). All eight patients with CMV in urine or blood upon entry into the study had negative urine and blood cultures at the end of induction. After induction therapy, seven patients continued maintenance foscarnet therapy, 60 mg/kg as a single daily infusion, 5 days/week. In six patients, retinal lesions increased in size after 2 to 32 weeks of maintenance therapy. One was invaluable because a retinal detachment developed. Only 9 of 42 blood and urine cultures obtained during maintenance foscarnet therapy yielded CMV, compared with 7 of 14 obtained prior to the initiation of foscarnet induction therapy (P = 0.04). Foscarnet toxicity was mild and infrequent: elevation in serum creatinine by 0.5 to 1.3 mg/dl over the base line (two patients), muscle twitching (three patients), hemoglobin decrease by 1 mg/dl (two patients), nausea (two patients), absolute neutrophil count decrease by 50% (one patient), rise in serum phosphorus to greater than 5.5 mg/dl (four patients), and proteinuria (two patients). Intermittently administered intravenous foscarnet appears to be an effective, relatively nontoxic therapy for CMV retinitis. Additional studies to determine the optimal dosage for maintenance therapy are needed, as are comparative trials with ganciclovir.