A PHASE 2, RANDOMIZED, DOUBLE-MASKED, PLACEBO-CONTROLLED, PARALLEL GROUP, MULTI-CENTER STUDY TO COMPARE THE EFFICACY AND SAFETY OF A CHEMOKINE CCR2/5 RECEPTOR ANTAGONIST (PF-04634817) WITH THAT OF RANIBIZUMAB IN ADULT SUBJECTS WITH DIABETIC MACULAR EDEMA (B1261009)