A Study to Evaluate THR-687 Treatment for Diabetic Macular Oedema.

In Part A, approximately 12 subjects are planned to be randomized (1:1 allocation) to THR-687 1.2mg and THR-687 2.0mg. In Part B, in the cohort of Treatment Naïve subjects are planned to be randomized (2:1 allocation) to THR-687 selected dose level from Part A and Aflibercept 2.0mg. In Part B, in the cohort of Previously Treated subjects are planned to be randomized (1:1 allocation) to THR-687 selected dose level from Part A and Aflibercept 2.0mg. All subjects in the study will receive study treatment in one selected study eye only.