A Study to Evaluate the Efficacy, Durability, and Safety of KSI-301 Compared to Aflibercept in Patients With Macular Edema Due to Retinal Vein Occlusion (RVO)

Inclusion Criteria: 1. Signed informed consent prior to participation in the study. 2. Treatment-naïve macular edema of 6 months duration or less due to CRVO or BRVO. Participants with hemiretinal vein occlusion will be included as CRVO. 3. BCVA ETDRS letter score between 80 and 25 (20/25 to 20/320 Snellen equivalent), inclusive in the Study Eye. 4. CST of ≥ 320 microns on SD-OCT (Heidelberg Spectralis or equivalent on other OCT instruments) as determined by the Reading Center 5. Decrease in vision determined by the Investigator to be primarily the result of ME secondary to RVO. 6. Other protocol-specified inclusion criteria may apply. Exclusion Criteria: 1. Macular edema in the Study Eye for reasons other than RVO 2. Active iris or angle neovascularization, neovascular glaucoma, neovascularization of the optic disc, retinal neovascularization or vitreous hemorrhage in the Study Eye. 3. Uncontrolled glaucoma in the Study Eye. 4. Active retinal disease other than the condition under investigation in the Study Eye. 5. Any history or evidence of a concurrent ocular condition present, that in the opinion of the Investigator could require either medical or surgical intervention alter visual acuity during the study 6. Active or suspected ocular or periocular infection or inflammation 7. Any prior use of an approved or investigational treatment for macular edema secondary to RVO in the Study Eye (e.g. anti-VEGF, intraocular or periocular steroids, macular laser photocoagulation). 8. Women who are pregnant or lactating or intending to become pregnant during the study. 9. Uncontrolled blood pressure defined as a systolic value ≥ 180 mmHg or diastolic value ≥100 mmHg while at rest 10. Recent history (within the 6 months prior to screening) of myocardial infarction, stroke, transient ischemic attack, acute congestive heart failure or any acute coronary event. 11. History of a medical condition that, in the judgment of the Investigator, would preclude scheduled study visits, completion of the study, or a safe administration of investigational product. 12. Other protocol-specified exclusion criteria may apply.