Abstract
Purpose:
To determine if RBZ’s favorable effect on diabetic retinopathy (DR) during the RIDE/RISE trials was durable after conversion from monthly to PRN therapy during the OLE. In addition, to understand whether a 2-year delay in RBZ therapy impacts long-term ocular outcomes.
Methods:
During RIDE/RISE, patients (pts) (n=759) received monthly 0.3 mg RBZ, 0.5 mg RBZ, or sham injection with rescue laser for diabetic macular edema (DME). Sham pts crossed over to monthly 0.5 mg RBZ at month (mo) 24. After 36 mos follow-up, 500 pts entered the OLE and received 0.5 mg RBZ per a criteria-based PRN regimen. DR severity was graded from 7-standard field fundus photographs. BCVA and proliferative DR (PDR)-related events were also recorded.
Results:
Rates of DR improvement from baseline were greater and rates of DR worsening were less in RBZ vs sham/crossover groups in the core studies and these differences were maintained during the OLE. At mo 48, rates for prior 0.3 mg RBZ, 0.5 mg RBZ, and sham/crossover, respectively, were 27%, 36% and 21% for ≥2-step and 11%, 8%, and 5% for ≥3-step improvement. Respective rates were 2%, 3%, and 11% for ≥2-step and 2%, 1%, and 7% for ≥3-step DR worsening. Risk of a new PDR-related event was also reduced with monthly RBZ during RIDE/RISE, and switching from monthly to PRN therapy did not seem to increase incidence of such events: cumulative probability at mo 12/24/36/48 among pts in the OLE was 5/12/15/20% for 0.3 mg RBZ, 6/10/15/20% for 0.5 mg RBZ and 18/30/35/38% for sham/crossover. Although probability of PDR events decreased dramatically in the sham group after crossover to RBZ at mo 24 (from 12% in year 2 to 6% in year 3), the cumulative probability of PDR events was higher in sham (38%) vs RBZ-treated eyes at mo 48. BCVA gain of ≥15 letters at mo 24 was more common in RBZ-treated eyes with ≥2 or ≥3-step DR improvement (52% and 45% of pts, respectively) compared with those with no change, worsening, or 1-step improvement (20%-40%).
Conclusions:
Monthly RBZ therapy resulted in meaningful improvements in DR severity and decreased risk of PDR-related outcomes that were subsequently maintained with less-than-monthly RBZ in some pts. DR improvement was also generally associated with greater vision gain. Delayed as compared to prompt RBZ therapy may result in less DR improvement and greater risk of PDR outcomes over the long-term.