Background and objective: An intravitreal device administering ganciclovir in a sustained-release fashion has been developed for site-specific therapy of cytomegalovirus (CMV) retinitis. The initially tested devices released ganciclovir at a rate of approximately 2 micrograms/hour (Mark I device), yielding an estimated in vivo therapeutic life span of 4 months. This report describes the initial clinical results of a longer-lasting device that releases ganciclovir at a rate of 1 microgram/hour (Mark II device), designed to be effective for up to 8 months.
Patients and methods: Over a 15-month time period, a total of 39 Mark II intravitreal ganciclovir devices were placed in 35 eyes of 29 patients with a diagnosis of CMV retinitis. At the time of implantation, none of the patients were on systemic anti-CMV therapy.
Results: Of the first 29 eyes of the 29 enrolled patients implanted with their initial Mark II device, 28 (97%) had no progression of retinitis at the 4-week postoperative examination. Survival analysis of these initial 29 implants revealed the median time to disease progression was 29.3 weeks (205 days). Serious ocular complications included one case of acute bacterial endophthalmitis (2.9% of eyes or 2.5% of implantations), and four cases of rhegmatogenous retinal detachment (four of 35 or 11.4% of eyes). Of the 10 patients with initially unilateral retinitis, four (40%) eventually developed contralateral disease. Five clinically suspected cases of extraocular, systemic CMV disease occurred during the study (17.2% of patients), necessitating reinstitution of systemic therapy.
Conclusion: This small, uncontrolled pilot study indicates that the Mark II (1 mg/hour) sustained-release intravitreal ganciclovir device is effective for local control of CMV retinitis.