Part 1 (DR without CI-DME): Inclusion Criteria: * Patients 25-89 years of age with a diabetic retinopathy (DR) diagnosis of nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) secondary to diabetes mellitus Type 1 or 2 for which PRP or anti-VEGF injections can be safely deferred for at least 6 months * HbA1c \< 12%. * Best corrected visual acuity (BCVA) Early Treatment Diabetic Retinopathy Study (ETDRS) letter score in the study eye of ≥69 letters (approximate Snellen equivalent of 20/40 or better). * Prior history of CI-DME in the study eye is acceptable. * Must be willing and able to provide written, signed informed consent. Exclusion Criteria: * Neovascularization in the study eye from a cause other than DR. * Presence of any active CI-DME. * Active or history of retinal detachment in the study eye. * Any evidence or documented history of PRP or retinal laser in the study eye. * Patients who had a prior vitrectomy surgery. * Women of childbearing potential. Part 2 (DR with CI-DME): Inclusion Criteria: * Patients 25-89 years of age with diabetic retinopathy secondary to diabetes mellitus Type 1 or 2. * HbA1c \< 12% * Macular thickening secondary to DME involving the center of the fovea, CST on SD-OCT (≥ 325 μm) * Best corrected visual acuity (BCVA) Early Treatment Diabetic Retinopathy Study (ETDRS) letter score in the study eye of 78-25 letters (approximate Snellen equivalent of 20/32 to 20/320) * Participants must have demonstrated a meaningful response to anti-VEGF therapy. * Must be willing and able to provide written, signed informed consent Exclusion Criteria: * Neovascularization in the study eye from a cause other than DR. * Active or history of retinal detachment in the study eye. * Any evidence or documented history of PRP or retinal laser in the study eye. * Patients who had a prior vitrectomy surgery. * Women of childbearing potential. Note: Other inclusions/exclusions criteria apply.