The Effect of the Oral PKC Inhibitor Ruboxistaurin on Vision Loss in Two Phase 3 Studies
ABSTRACT PURPOSE: To assess the effect of ruboxistaurin (RBX) on vision loss through a prospectively-defined combined analysis of two phase 3 trials (MBDL and MBCU). Methods: Patients in both of these three-year, randomized, placebo controlled, double masked trials had best corrected ETDRS visual acuity (VA) ≥75 letters (~20/32 Snellen), ETDRS retinopathy level 20-47D (MBDL) or 35-53E (MBCU), and no prior panretinal or focal photocoagulation in at least 1 eye at baseline. Patients received oral placebo (N=508 total from both studies) or RBX 32 mg/day (N=520 total). Best-corrected ETDRS VA was measured at 6 month intervals for 3 years (MBDL) or for 18-48 months (MBCU). Sustained moderate visual loss (SMVL) was defined as a 15-letter or more reduction from baseline in VA sustained for a patient's last 6 months of study participation. Results: In the combined studies (N=1028 total), SMVL occurred in 4.4% of placebo- vs 2.3% of RBX treated patients (P=0.069). In patients with a minimum of 2 years of follow-up (N=825 total) there was less SMVL in the RBX group (4.4% placebo vs. 2.1% RBX, p=0.045). Other VA-related measures (mean VA, contrast sensitivity, VFQ-25 questionnaire) either trended towards a benefit for RBX or were also statistically significant in favor of RBX. In contrast, DME morphology-related measures (occurrence of significant center of macula involvement, OCT-determined center of macula thickness, application of focal photocoagulation) did not show a consistent trend in favor of or against RBX. Conclusion: SMVL data in a prospectively defined combined analysis from these two phase 3 trials suggest a similar magnitude of effect of RBX on vision loss as seen in two prior studies (approximately 50% reduction above standard care). However event rates were low and statistical significance was not achieved.
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ABSTRACT: Objective: To examine the relationship between subclinical diabetic macular edema (DME) and the development of clinically significant macular edema (CSME) in nonproliferative diabetic retinopathy (NPDR) in patients with type 2 diabetes. Methods: A prospective, monocenter, observational study was designed to follow patients/eyes with type 2 diabetes and NPDR (Early Treatment Diabetic Retinopathy Study levels 20 and 35) with no prior laser treatment for 2 years or until development of CSME. Ophthalmologic examinations, including best-corrected visual acuity, fundus photography and optical coherence tomography (OCT), were performed at baseline, 6 months and a final visit. Results: A total of 348 patients completed study follow-up; 26 eyes developed CSME. Six out of 32 eyes/patients presenting subclinical DME at baseline developed CSME (18.7%), while 20 out of 316 eyes without subclinical DME developed CSME (6.3%). Eyes/patients with subclinical DME presented a risk for DME progression 3.686 times higher than that of eyes/patients without subclinical DME (95% confidence interval 1.221-7.988). Conclusions: Subclinical DME in eyes with NPDR identified by center point thickness measured on a Stratus OCT is a good predictor of CSME development. © 2013 S. Karger AG, Basel.Ophthalmologica 09/2013; 230(4). DOI:10.1159/000354550 · 1.87 Impact Factor
- Middle East African journal of ophthalmology 10/2013; 20(4):271-2. DOI:10.4103/0974-9233.119991
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ABSTRACT: Diabetic retinopathy (DR), the most common long-term complication of diabetes mellitus, remains one of the leading causes of blindness worldwide. Tight glycemic and blood pressure control has been shown to significantly decrease the risk of development as well as the progression of retinopathy and represents the cornerstone of medical management of DR. The two most threatening complications of DR are diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). Focal/grid photocoagulation and panretinal photocoagulation are standard treatments for both DME and PDR, respectively. Focal/grid photocoagulation is a better treatment than intravitreal triamcinolone acetonide in eyes with DME. Currently, most experts consider combination focal/grid laser therapy and pharmacotherapy with intravitreal antivascular endothelial growth factor agents in patients with center-involving DME. Combination therapy reduces the frequency of injections needed to control edema. Vitrectomy with removal of the posterior hyaloid seems to be effective in eyes with persistent diffuse DME, particularly in eyes with associated vitreomacular traction. Emerging therapies include fenofibrate, ruboxistaurin, renin-angiotensin system blockers, peroxisome proliferator-activated receptor gamma agonists, pharmacologic vitreolysis, and islet cell transplantation.Middle East African journal of ophthalmology 10/2013; 20(4):273-82. DOI:10.4103/0974-9233.119993