A Study to Evaluate the Efficacy and Safety of Orally Administered VX-01

This is a Phase 2, multi-center, double-masked, randomized, placebo-controlled, parallel group study to evaluate the efficacy of oral doses of VX-01 in subjects with moderate to severe NPDR, without CI-DME. Approximately 100 male and female subjects aged ≥ 18 years with a documented diagnosis of Type 1 Diabetic Mellitus or Type 2 Diabetic Mellitus with moderate to severe NPDR (without CI-DME) will be enrolled, if they meet all the eligibility criteria for the study. Subjects will be randomized 1:1 to 1 of 2 study cohorts: * Cohort 1 (n = 50): VX-01 (film-coated tablets, 150 mg administered BID) * Cohort 2 (n = 50): Placebo (film-coated tablets, administered BID) Subjects will be stratified by the presence or absence of proliferative diabetic retinopathy (PDR) and by glycated hemoglobin (HbA1c) of ≥ 8.5% or \< 8.5% at Screening. All subjects will take 1 tablet of VX-01 or placebo BID for 52 consecutive weeks. All subjects will be followed for 12 weeks after completion of treatment at Week 52. The Sponsor, study site staff, monitors, personnel, and subjects will be masked to treatment assignment during the entirety of the study.