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 μm for the low-dose group and 197.8±85.9 μm 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.