A pilot study of multiple intravitreal injections of ranibizumab in patients with center-involving clinically significant diabetic macular edema

Objective: To evaluate the biologic activity of multiple intravitreal injections of ranibizumab in patients with center-involving clinically significant diabetic macular edema (DME) and to report any associated adverse events. Design: Single-center, open-label, dose-escalating pilot study. Participants: A total of 10 eyes of 10 patients (mean age, 69.3 years [range, 59-81]) with DME involving the center of the macula and best-corrected visual acuity (BCVA) in the study eye between 20/63 and 20/400. Intervention: Three intravitreal injections of ranibizumab (0.3 mg or 0.5 mg each injection) administered on day 0, month 1, and month 2, and observation until month 24. Main Outcome Measures: Primary end points were the frequency and severity of ocular and systemic adverse events. Secondary end points were BCVA and measurement of retinal thickness by optical coherence tomography. Results: Of the 10 patients enrolled, 5 received 0.3-mg and 5 received 0.5-mg ranibizumab. Intravitreal injections of ranibizumab were well tolerated. No systemic adverse events were reported. Five occurrences of mild to moderate ocular inflammation were reported. At month 3, 4 of 10 patients gained >= 15 letters, 5 of 10 gained >= 10 letters, and 8 of 10 gained >= 1 letters. At month 3, the mean decrease in retinal thickness of the center point of the central subfield was 45.3 +/- 196.3 mu m for the low-dose group and 197.8 +/- 85.9 mu m for the high-dose group. Conclusions: Ranibizumab appears to be a well-tolerated therapy for patients with DME. This pilot study demonstrates that ranibizumab therapy has the potential to maintain or improve BCVA and reduce retinal thickness in patients with center-involved clinically significant DME.