Central retinal artery occlusion (CRAO) is an ophthalmologic emergency which leads to severe and permanent vision loss. There is no evidence-based therapy for CRAO. The objective of this GION study is to evaluate the efficacy and safety of KUS121 intravitreal (IVT) injection in participants with acute non-arteritic CRAO.

This is a Phase II, double-masked, sham-controlled, multi-center, parallel-group study to evaluate the efficacy and safety of KUS121 intravitreal (IVT) injection in patients with non-arteritic Central Retinal Artery Occlusion (CRAO) diagnosed and treated within 3-48 hours of disease onset. Participants will be randomized to high dose KUS121, low dose KUS121, or sham in a 1:1:1 ratio. Participants will receive daily intravitreal injections of KUS 121 or sham, which mimics an injection, from Day 1 through Day 3. Primary efficacy endpoint is the proportion of participants who gain 15 letters or more in BCVA compared with baseline and will be assessed at Week 12. Safety evaluation will continue until a 12-month follow up.

Inclusion Criteria:

• Participants who are willing and able to comply with clinic visits and study-related procedures and able to provide signed informed consent in person or from their legally authorized representative
• Males and females ≥ 20 years of age at that time of providing signed informed consent
• Diagnosed as non-arteritic Central Retinal Artery Occlusion from 3 hours until no more than 48 hours after the onset of significant visual acuity changes
• Best Corrected Visual Acuity (BCVA) Early Treatment Diabetic Retinopathy Study (ETDRS) letter score of 0 to 35 in the study eye at screening prior to enrollment (eyes with 'no light perception' or 'light perception' are to be excluded)
• Retinal thickening or hyper-reflectivity in retinal inner layers in spectral domain optical coherence tomography (SD-OCT), or white turbid edema in fundus examination

Exclusion Criteria:

• Presence of the following conditions in the study eye:

  1. Infection in or around the eye
  2. Uncontrolled intraocular pressure
  3. Abnormality in macula other than CRAO findings
  4. History of macular photocoagulation
  5. Opacity in visual axis preventing fundus examination or fundus imaging (e.g., corneal dystrophy)
  6. Neovascularization of iris and retina
  7. Any inflammatory disease involving the eye
  8. Optic atrophy
  9. Glaucomatous cupping greater than 0.9
  10. Prior vitrectomy
  11. Aphakia with the absence of posterior capsule
  12. Any IVT injection or sub-Tenon's injection within 1 month of screening
  13. Any intraocular surgery or ocular implant within 3 months of screening
  14. Any history of ocular trauma within 3 months of screening

• Thrombolytic, fibrinolytic or prostaglandin E1 systemic treatment within 1 month of screening

• A positive urine pregnancy test on Day 1 prior to study enrollment

• History of allergy or hypersensitivity to KUS121 or a compound with a condensed polycyclic aromatic hydrocarbon skeleton represented by naphthalene and any of excipients of KUS121 product, fluorescein, or any study treatment-related mandatory ingredients that is not amenable to treatment

• Known hypersensitivity to a study treatment procedure, dilating drops, or any of the anesthetic and antimicrobial preparations used by a participant during the study

• Presence of other medical disease, physical or ocular examination finding, or clinical laboratory finding that in the opinion of the Investigator contraindicates the use of an investigational product, might interfere with the evaluation of the efficacy or safety of the study drug, may put the participant at significant risk or might interfere with the participant's ability to participate in the study