Treatment outcomes of reduced-dose intravitreal ganciclovir for cytomegalovirus retinitis

BACKGROUND: Cytomegalovirus retinitis (CMVR) is one of the most common opportunistic infection in immunocompromised individuals. Intravitreal ganciclovir injection has been used successfully but no standard regimen was established. Risks of drug toxicity, endophthalmitis, and injection-related complications increased with number and frequency of injection. The aim of this study is to evaluate the outcomes of reduced-dose intravitreal ganciclovir (2 mg/0.04 mL) for the treatment of CMVR. METHODS: A prospective observational cohort study involving 67 eyes of 49 patients with CMVR was performed. Induction therapy involved intravenous ganciclovir (10 mg/kg/day) for 2 weeks unless contraindicated or patients refused. Patients were then treated with reduced-dose intravitreal ganciclovir every week for 4 weeks, and then every other week until the lesion healed. The patients’ demographic data were recorded, and vision parameters were examined every visit. RESULTS: Twenty eyes (29.9 %) presented with initial visual acuities less than 6/60. The majority of patients were diagnosed with CMVR in zones 1 or 2 (63 eyes, 94 %), and, at least, one quadrant of the retina was involved (56 eyes, 83.6 %). Forty-one eyes (61.2 %) completely resolved after treatment within the 6-month follow-up. There was no significant difference in healing time, whether or not patients received induction treatment with intravenous ganciclovir (111.00 ± 12.96 vs 105.00 ± 28.32 days, p = 0.8). Five eyes (12.2 %) of patients with healed CMVR had visual acuities less than 6/60. CONCLUSIONS: Reduced-dose intravitreal ganciclovir is a safe and effective treatment option. It provides comparable results to other weekly regimens. Induction with intravenous ganciclovir is not crucial in a resolution of retinitis, although it may be necessary to reduce systemic cytomegalovirus loads and mortality rates. TRIAL REGISTRATION: The trial was registered with Thai Clinical Trials Registry (TCTR) on 16 March 2016 – TCTR20160316001.