Safety and Effect on Central Retinal Thickness of BI 1026706 in Patients With Diabetic Macular Edema

Inclusion criteria: * Patients 18 years of age and older * Male patients or female patients of non-childbearing potential * Diagnosis of Diabetes mellitus type 1 or type 2 * Retinal thickening due to Diabetic macular edema (DME) involving the center of the macula in the study eye as confirmed by the Investigator on clinical exam * Center-involved DME confirmed on Spectral-Domain Optical Coherence Tomography (SD-OCT) with central subfield thickness (CSFT) of at least 300 µm in the study eye at screening, confirmed by Central Reading Centre * Best corrected visual acuity ETDRS (Early Treatment Diabetic Retinopathy Study) letter score in the study eye of 84 or below, but at least 70 at screening * Further inclusion criteria apply Exclusion criteria: * Macular edema considered to be due to other causes than DME in the study eye * Additional eye disease in the study eye that, in the opinion of the Investigator, might affect macular edema or could compromise or alter visual acuity during the course of the trial * Anterior segment and vitreous abnormalities in the study eye that would compromise the adequate assessment of the best corrected visual acuity or an adequate examination of the posterior pole * Intraocular surgery in the study eye within 4 months prior to randomization or planned intraocular surgery, including cataract, during the study period * Proliferative diabetic retinopathy or iris neovascularisation in the study eye * Aphakia in the study eye * Any indication that requires immediate treatment or for which treatment is expected in the study eye with anti-Vascular Endothelial Growth Factor (VEGF) or with laser photocoagulation during the period, as per Investigator's judgment * History of prior laser photocoagulation or other surgical, intravitreal or peribulbar treatment in the study eye within 4 months prior to randomization, either for DME or an ocular condition other than DME * History of fluocinolone acetonide intravitreal implant in the study eye * Application of intraocular corticosteroids in the study eye within 2 years prior to randomization in phakic eyes or 9 months in pseudophakic eyes * History of topical steroid or nonsteroidal anti-inflammatory drugs (NSAID) treatment in the study eye within 30 days prior to randomization * Systemic anti-VEGF or pro-VEGF treatment within 4 months prior to randomization * Initiation of intensive insulin treatment (multiple daily injections or a pump) within 3 months prior to randomization or plans to do so in the next 4 months * Change in oral antidiabetic medication within 3 months prior to randomization * Patients with a clinically relevant abnormal screening haematology, blood chemistry, or urinalysis * Renal impairment with estimated creatinine clearance \< 30 mL/min (as calculated by Cockcroft-Gault equation) * Myocardial infarction or unstable angina pectoris within 3 months before randomization * Uncontrolled arterial hypertension defined as a single measurement of systolic \>180 mmHg, two consecutive measurements of systolic \>160 mmHg, or diastolic \>100mmHg on optimal medical regimen * Further exclusion criteria apply