Efficacy and safety of ranibizumab 0.5 mg in patients with visual impairment due to macular edema secondary to central retinal vein occlusion: Design and baseline characteristics of the CRYSTAL study

Abstract

 

Purpose

 

To evaluate the efficacy and safety of ranibizumab 0.5 mg, administered according to a stability-criteria-driven, pro re nata (PRN) dosing regimen over 24 months (M), in patients with visual impairment due to macular edema (ME) secondary to central retinal vein occlusion (CRVO). Spectral domain optical coherence tomography data have been collected to gain further insights into predictive factors for disease progression and to evaluate the possibility of reduced monitoring. Here we describe the study design and baseline characteristics of patients enrolled in the CRYSTAL study.

 

Methods

 

In this ongoing 24M, phase IIIb, open-label, single-arm, multicenter study, all patients receive monthly ranibizumab 0.5 mg until visual acuity (VA) is stable for 3 consecutive visits (phase A). Thereafter patients are monitored monthly for VA and disease activity and would re-enter phase A upon signs of deterioration (based on treating physicians assessment). As of M12, the frequency of monitoring visits can be reduced to every 2M for patients with stable VA and an absence of disease activity. Key objectives/endpoints: to evaluate the efficacy of an individualized, stability-criteria-driven PRN dosing regimen of ranibizumab 0.5 mg as assessed by the mean change in best-corrected visual acuity (BCVA) at M12 compared to baseline (primary endpoint); mean change in BCVA and central subfield thickness from baseline to M1 through M12 and 24; safety profile over 24M.

 

Results

 

356 patients with visual impairment due to ME secondary to CRVO are enrolled in the study from 78 sites in Europe, Australia and Canada. The mean age at baseline is 65.5 years and 64% of the patients are male.

 

Conclusions

 

Baseline demographics such as age and gender are comparable to those observed in the pivotal CRUISE study, which will allow comparison of the pivotal study regimen with the individualized stability-criteria-driven PRN dosing regimen as approved in the European Union. The long-term safety and efficacy data from this study will further guide the recommendations of ranibizumab treatment in CRVO.

 

Keywords: 585 macula/fovea • 505 edema • 748 vascular endothelial growth factor