title: The effect of the oral PKC β inhibitor ruboxistaurin on vision loss in two phase 3 studies.
abstract: OBJECTIVE
  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 3-year randomized, placebo-controlled, double-masked trials had best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) ≥ 75 letters (∼20/32 Snellen), ETDRS retinopathy level 20 to 47D (MBDL) or 35B to 53E (MBCU), and no prior panretinal or focal photocoagulation in at least one eye at baseline. Patients received oral placebo (N = 508 total from both studies) or RBX 32 mg/d (N = 520 total). Best-corrected ETDRS VA was measured at 6-month intervals for 3 years (MBDL) or for 18 to 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- versus 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 versus 2.1% RBX, P = 0.045). Other VA-related measures (mean VA, contrast sensitivity, Visual Functioning Questionnaire 25 [VFQ-25]) either trended toward a benefit for RBX or were also statistically significant in favor of RBX. In contrast, diabetic macular edema (DME) morphology-related measures (occurrence of significant center of macula involvement, optical coherence tomography [OCT]-determined center of macula thickness, application of focal photocoagulation) did not show a consistent trend in favor of or against RBX.
  
  
  CONCLUSIONS
  SMVL data in a prospectively defined combined analysis from these two phase 3 trials suggest a magnitude of effect of RBX on vision loss similar to that seen in two prior studies (approximately 50% reduction above standard care). However, event rates were low and statistical significance was not achieved. (ClinicalTrials.gov numbers, NCT00133952, NCT00090519.).
authors: Eli Lilly and Company, Indianapolis, IN 46285, USA. msheetz@lilly.com
authors: Matthew J
authors: MJ
authors: Sheetz
authors: Lloyd Paul
authors: LP
authors: Aiello
authors: Matthew D
authors: MD
authors: Davis
authors: Ronald
authors: R
authors: Danis
authors: Toke
authors: T
authors: Bek
authors: Jose
authors: J
authors: Cunha-Vaz
authors: Nazila
authors: N
authors: Shahri
authors: Paul H
authors: PH
authors: Berg
mesh_terms: D000284:Administration, Oral; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D004311:Double-Blind Method; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007211:Indoles / Q000008:administration & dosage / Q000627:therapeutic use*; D008269:Macular Edema / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008301:Maleimides / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D011446:Prospective Studies; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D064546:Protein Kinase C beta; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D041623:Tomography, Optical Coherence; D014786:Vision Disorders / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; C099154:ruboxistaurin; D011493:Protein Kinase C; D064546:Protein Kinase C beta