The primary objective of the study is to investigate the safety and tolerability of intravitreal (IVT) REGN910-3 and IVT REGN910 in patients with neovascular age-related macular degeneration (AMD), and separately in patients with diabetic macular edema (DME).

Key Inclusion Criteria:

1. For patients with AMD:

   1. Active subfoveal choroidal neovascularization (CNV) secondary to AMD, including juxtafoveal lesions that affect the fovea as evidenced by FA or OCT in the study eye, as determined by the investigator
   2. Men or women ≥50 years and older

2. For patients with DME:

   1. Patients with clinically significant DME with central involvement (≥300 μm in the central subfield on spectral domain OCT)
   2. Men or women ≥18 years and older

Key Exclusion Criteria:

1. For patients with neovascular AMD:

   1. Evidence of choroidal neovascularization (CNV) due to any cause other than AMD in either eye
   2. Evidence of diabetic retinopathy (DR) or DME in either eye

2. For patients with DME: Evidence of neovascular AMD or CNV due to any cause in either eye

3. Prior IAI in either eye

4. IVT bevacizumab, ranibizumab, or pegaptanib sodium in the study eye within 8 weeks of day 1 or an AE with any of these previous treatments that would preclude administration of drug in this study

5. Any prior treatment with angiopoietin inhibitors

6. Any prior systemic (IV) anti-VEGF administration

7. History of vitreoretinal surgery in the study eye

8. Pan retinal laser photocoagulation or macular laser photocoagulation in the study eye within 3 months of the screening visit

9. Previous use of intraocular or periocular corticosteroids in the study eye within 4 months of screening

(The inclusion/ exclusion criteria provided above are not intended to contain all considerations relevant to a subject's potential participation in this clinical trial).