Studies of the Ocular Complications of AIDS (SOCA)--HPMPC Peripheral CMV Retinitis Trial (HPCRT)

CMV retinitis is the most common intraocular infection in patients with AIDS and is estimated to affect 35 percent to 40 percent of patients with AIDS. Untreated CMV retinitis is a progressive disorder, the end result of which is total retinal destruction and blindness. As of September 1997, drugs approved by the United States Food and Drug Administration (FDA) for the treatment of CMV retinitis were ganciclovir (Cytovene), foscarnet (Foscavir), and cidofovir (Vistide). Cidofovir has a prolonged duration of effect permitting intermittent administration. All systemically administered anti-CMV drugs are given in a similar fashion consisting of initial 2-week high-dose treatment (induction) to control the infection followed by long-term lower dose treatment (maintenance) to prevent relapse. Cidofovir is administered as an intravenous infusion once weekly for induction therapy and once every 2 weeks as maintenance therapy. The HPCRT evaluated the efficacy and safety of cidofovir therapy.

The HPCRT was a multicenter, randomized, controlled clinical trial of cidofovir for the treatment of CMV retinitis. Patients with small peripheral CMV retinitis lesions (i.e., not at risk of immediate loss of visual acuity) were randomized to immediate treatment with cidofovir or deferred therapy until the retinitis had progressed 750 ýým. Patients randomized to immediate therapy received either 1) low-dose cidofovir at 5 mg/kg once weekly induction for 2 weeks, followed by 3 mg/kg once every 2 weeks for maintenance or 2) high-dose cidofovir at 5 mg/kg once weekly induction for 2 weeks followed by 5 mg/kg once every 2 weeks for maintenance. Patients whose retinitis progressed were given treatment according to best medical judgement, and those assigned to deferral were generally treated with cidofovir.

Outcomes in this trial included retinitis progression, loss of retinal area, and morbidity.