Effect of ruboxistaurin on visual loss in patients with diabetic retinopathy.
OBJECTIVE
To evaluate the effect of ruboxistaurin, an orally administered protein kinase C beta (PKC beta) isozyme-selective inhibitor, on vision loss in patients with diabetes.


METHODS
Thirty-six-month, randomized, double-masked, placebo-controlled, parallel, multicenter trial.


METHODS
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 degrees 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 > or =45 letters, retinopathy level > or = 47A and < or = 53E, and no prior panretinal photocoagulation in at least one eye.


METHODS
Effect of oral ruboxistaurin (32 mg/day) on reduction of sustained moderate visual loss (> or =15-letter decrease in ETDRS VA score maintained > or = 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 > or =15 letters was more frequent (4.9% vs. 2.4%) and > or =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 microm from the center of the macula at baseline, ruboxistaurin treatment was associated with less frequent progression of edema to within 100 microm (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).


CONCLUSIONS
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.
Beetham Eye Institute, Joslin Diabetes Center, 1 Joslin Place, Boston, MA 02215, USA. LPAiello@Joslin.Harvard.edu
Aiello
Lloyd Paul
LP
Davis
Matthew D
MD
Girach
Aniz
A
Kles
Keri A
KA
Milton
Roy C
RC
Sheetz
Matthew J
MJ
Vignati
Louis
L
Zhi
Xin Eric
XE
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003930:Diabetic Retinopathy / Q000188:drug therapy*; D018450:Disease Progression; D004311:Double-Blind Method; D004791:Enzyme Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007211:Indoles / Q000009:adverse effects / Q000627:therapeutic use*; D008269:Macular Edema / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D008301:Maleimides / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D064546:Protein Kinase C beta; D014786:Vision Disorders / Q000517:prevention & control; D014792:Visual Acuity / Q000187:drug effects*
D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; C099154:ruboxistaurin; D011493:Protein Kinase C; D064546:Protein Kinase C beta