Effect of Ruboxistaurin on Visual Loss in Patients with Diabetic Retinopathy
Data presented in part at: American Academy of Ophthalmology scientific sessions, October 2005, Chicago, Illinois.
Received 1 May 2006; accepted 19 July 2006. published online 20 September 2006.
Objective
To evaluate the effect of ruboxistaurin, an orally administered protein kinase C β (PKC β) isozyme-selective inhibitor, on vision loss in patients with diabetes.
Six hundred eighty-five patients randomized at 70 clinical sites.
Methods
Ophthalmologic examination was performed at screening and at each 3-month visit. Retinopathy status was assessed every 6 months with Early Treatment Diabetic Retinopathy Study (ETDRS) standard 7-field 30° color stereoscopic fundus photography. Levels of diabetic retinopathy and diabetic macular edema were determined by 2 independent graders masked to site and treatment assignment, with additional independent adjudication as required. Eligible patients had a best-corrected visual acuity (VA) score of ≥45 letters, retinopathy level ≥ 47A and ≤ 53E, and no prior panretinal photocoagulation in at least one eye.
Main Outcome Measure
Effect of oral ruboxistaurin (32 mg/day) on reduction of sustained moderate visual loss (≥15-letter decrease in ETDRS VA score maintained ≥ 6 months) in patients with moderately severe to very severe nonproliferative diabetic retinopathy.
Results
Sustained moderate visual loss occurred in 9.1% of placebo-treated patients versus 5.5% of ruboxistaurin-treated patients (40% risk reduction, P = 0.034). Mean VA was better in the ruboxistaurin-treated patients after 12 months. Baseline–to–end point visual improvement of ≥15 letters was more frequent (4.9% vs. 2.4%) and ≥15-letter worsening was less frequent (6.7% vs. 9.9%) in ruboxistaurin-treated patients relative to placebo (P = 0.005). When clinically significant macular edema was >100 μm from the center of the macula at baseline, ruboxistaurin treatment was associated with less frequent progression of edema to within 100 μm (68% vs. 50%, P = 0.003). Initial laser treatment for macular edema was 26% less frequent in eyes of ruboxistaurin-treated patients (P = 0.008).
Conclusion
Oral ruboxistaurin treatment reduced vision loss, need for laser treatment, and macular edema progression, while increasing occurrence of visual improvement in patients with nonproliferative retinopathy.
Correspondence to Lloyd Paul Aiello, MD, PhD, Beetham Eye Institute, Joslin Diabetes Center, 1 Joslin Place, Boston, MA 02215.
Manuscript no. 2006-498.
Study funded by Eli Lilly and Company, Indianapolis, Indiana.
ABSTRACT