The purpose of the study is to determine whether concentrations of FOV2304 (high dose or low dose) administered in the eye are more effective than placebo in treating patients with diabetic macular edema, following 12 weeks of treatment.

Main inclusion/exclusion criteria are listed below. Others may apply.

Inclusion Criteria:

1. Male or female, at least 18 years of age.
2. Diagnosis of diabetes mellitus
3. Patient must be able to self administer study drug.
4. Clinically significant diabetic macular edema in at least one eye ("study eye") involving the center of the macula:
5. Mild to severe non proliferative diabetic retinopathy (Early Treatment Diabetic Retinopathy Study [ETDRS] grade between 20 and 53).
6. BCVA score ≥ 34 letters and < 80 letters in the study eye.
7. Women of childbearing potential must have a negative urine pregnancy test at Screening and be using two highly effective methods of contraception throughout the study.
8. Male patients with partners of childbearing potential must agree to use at least one highly effective method of contraception throughout the study.

Exclusion Criteria:

Ocular conditions:

1. Any ocular condition in the study eye that in the opinion of the investigator would prevent improvement in visual acuity.

2. Proliferative diabetic retinopathy in the study eye.

3. History of panretinal scatter photocoagulation(PRP)in the study eye within 4 months prior to screening, and/or anticipated need for PRP in the 3 months following randomization.

4. Active optic disc or retinal neovascularization, rubeosis iridis, active or history of choroidal neovascularization in the study eye.

5. History of pars plana vitrectomy at any time, intraocular surgery in the study eye within 90 days prior to screening.

6. History of use of intravitreal injectable or periocular depots corticosteroids (other than triamcinolone acetonide)within 3 months prior to the screening visit in the study eye.

7. Patients who have previously received triamcinolone acetonide in the study eye:

   • The intended dose for each triamcinolone acetonide injection was more than 4 mg.
   • The most recent dose was less than 3 months prior to the screening visit.
   • Any treatment-related adverse event that was seen, and in the opinion of the investigator, has the potential to worsen or reoccur with study treatment.

8. Patients who have previously received anti-VEGF therapy within 3 months prior to the screening visit in the study eye.

9. Uncontrolled glaucoma or glaucoma treated by 2 or more medications.

10. Aphakia or intraocular lens placement in the anterior chamber of the study eye.

11. Any active ocular infection; any history of recurrent or chronic infection or inflammation in the study eye.

12. History of herpetic infection in either eye.

13. History of corneal pathology/surgery

14. Contact lens use at any time during the study.

    Systemic conditions:

15. Uncontrolled systemic disease.

16. Poorly controlled diabetes mellitus.

17. Impaired renal function

18. Poorly controlled arterial hypertension