Ranibizumab 0.5 mg for Diabetic Macular Edema with Bimonthly Monitoring after a Phase of Initial Treatment: 18-Month, Multicenter, Phase IIIB RELIGHT Study

Abstract

To evaluate ranibizumab 0.5 mg using bimonthly monitoring and individualized re-treatment after monthly follow-up for 6 months in patients with visual impairment due to diabetic macular edema (DME). A phase IIIb, 18-month, prospective, open-label, multicenter, single-arm study in the United Kingdom. Participants (N = 109) with visual impairment due to DME. Participants received 3 initial monthly ranibizumab 0.5 mg injections (day 0 to month 2), followed by individualized best-corrected visual acuity (BCVA) and optical coherence tomography-guided re-treatment with monthly (months 3-5) and subsequent bimonthly follow-up (months 6-18). Laser was allowed after month 6. Mean change in BCVA from baseline to month 12 (primary end point), mean change in BCVA and central retinal thickness (CRT) from baseline to month 18, gain of ≥10 and ≥15 letters, treatment exposure, and incidence of adverse events over 18 months. Of 109 participants, 100 (91.7%) and 99 (90.8%) completed the 12 and 18 months of the study, respectively. The mean age was 63.7 years, the mean duration of DME was 40 months, and 77.1% of the participants had received prior laser treatment (study eye). At baseline, mean BCVA was 62.9 letters, 20% of patients had a baseline BCVA of >73 letters, and mean baseline CRT was 418.1 μm, with 32% of patients having a baseline CRT <300 μm. The mean change in BCVA from baseline to month 6 was +6.6 letters (95% confidence interval [CI], 4.9-8.3), and after institution of bimonthly treatment the mean change in BCVA at month 12 was +4.8 letters (95% CI, 2.9-6.7; P < 0.001) and +6.5 letters (95% CI, 4.2-8.8) at month 18. The proportion of participants gaining ≥10 and ≥15 letters was 24.8% and 13.8% at month 12 and 34.9% and 19.3% at month 18, respectively. Participants received a mean of 6.8 and 8.5 injections over 12 and 18 months, respectively. No new ocular or nonocular safety findings were observed during the study. The BCVA gain achieved in the initial 6-month treatment period was maintained with an additional 12 months of bimonthly ranibizumab PRN treatment.