This is a prospective, randomized, subject- and evaluator-masked, Phase 2, multicenter study comparing the safety and efficacy of EC-104-6M high-dose (fluocinolone acetonide [FA] 0.14 mg) implant and EC-104-4M low-dose (FA 0.092 mg) implant to Ozurdex® (dexamethasone intravitreal (IVT) implant, 0.7 mg) in subjects with diabetic retinopathy (DR) and center-involving diabetic macular edema (DME), with prior suboptimal clinical response to IVT anti-VEGF therapy who have been previously treated with locally administered corticosteroids without a clinically significant rise in intraocular pressure (IOP).

Approximately 75 subjects who meet entry criteria will be randomized 1:1:1 to EC-104-6M high-dose (FA 0.14 mg) implant or EC-104-4M low-dose (FA 0.092 mg) implant or Ozurdex® (dexamethasone IVT implant 0.7 mg), with the goal of achieving approximately 20 subjects per group with a positive therapeutic response in their study eyes, who are evaluable in the primary endpoint analysis to assess efficacy. Subjects with a positive therapeutic response at Week 4 will be included in the primary and secondary endpoint analyses to assess efficacy for "Time to recurrent disease." Subjects who do not achieve a positive therapeutic response will be classified as suboptimal responders. While suboptimal responders will not be included in the primary and the secondary endpoint analyses to assess efficacy for "Time to recurrent disease," they will remain in the study and will be followed prospectively, with inclusion in the remaining endpoints to assess efficacy and all safety endpoint analyses

Inclusion Criteria:

1. Males or females who are at least 18 years of age at the time of informed consent

2. Willing and able to provide signed informed consent (participant or legally authorized representative) prior to any study-related procedures and to comply with all study visits and cooperate with all examinations

3. Diagnosis of diabetes mellitus (Type 1 or Type 2), with history of diabetic macular edema (DME) < = years duration prior to Screening Visit 1

4. Currently monitored hemoglobin A1c values ≤ 10.0 while under the care of a qualified medical provider for diabetes mellitus management, unless provider allows value variance

   Inclusion criteria for the study eye (all of the below criteria must be met in the same eye):

5. Early Treatment Diabetic Retinopathy Study BCVA score ≤ 70 letters (Snellen equivalent 20/40 or worse) and ≥ 20 letters (Snellen equivalent 20/400) in at least 1 eye

Exclusion Criteria:

1. Previous or current diagnosis of any form of glaucoma (defined as cup-to-disc ratio > 0.7) or ocular hypertension (documented intraocular pressure (IOP) > 21 mm Hg without glaucomatous disc damage) requiring medical or surgical intervention
2. History of steroid-induced IOP elevation > 25 mm Hg
3. Presence of active proliferative diabetic retinopathy, defined as active neovascularization of disc (NVD), neovascularization elsewhere (NVE), neovascularization of iris (NVI), neovascularization of angle (NVA), or vitreous hemorrhage in the setting of active NVD or NVE

Evaluators of efficacy study assessments will be masked. The injecting physician and the injection technician or clinical assistant preparing the IP for administration will be unmasked to the identity of the specific investigational product (IP)