Foscarnet therapy of cytomegalovirus retinitis in AIDS

Cytomegalovirus (CMV) infection may cause retinitis or inflammation of the retina, the inner lining of the eye; this is the most common cause of blindness in patients with acquired immunodeficiency syndrome (AIDS). The drug foscarnet was shown to inhibit viral deoxyribonucleic acid (DNA) polymerase, an enzyme involved in the formation of the viral DNA molecule which carries the genetic information of the CMV microorganism. Studies suggest that foscarnet may be effective in preventing the progression of CMV retinitis. The effectiveness of foscarnet was assessed in 17 patients with CMV retinitis. Foscarnet produced a complete response in eight patients, a partial response in eight patients, and no response in one case. The excretion of CMV in the urine was not decreased by foscarnet in 4 of 12 patients, despite improved retinal lesions. Adverse effects of foscarnet included: kidney failure, reflected by increased blood creatinine levels in 50 percent of patients and also the need for dialysis, the artificial filtration of the blood, in two patients; and anemia resulting in the need for blood transfusion in 10 patients. Among seven patients maintained on foscarnet therapy, four suffered recurrence of CMV retinitis, and only one remained in remission for longer than 24 weeks. The drug zidovudine did not worsen the incidence of side effects due to foscarnet use. Thus, foscarnet is effective in suppressing the activity of CMV in retinitis, although the suppression is not maintained. (Consumer Summary produced by Reliance Medical Information, Inc.)