A Study to Investigate Aqueous Humor and Multimodal Imaging Biomarkers in Treatment-Naïve Participants With Diabetic Macular Edema Treated With Faricimab

Inclusion Criteria: * Diagnosis of diabetes mellitus (Type 1 or Type 2), as defined by the World Health Organization (WHO) and/or American Diabetes Association * Hemoglobin A1c (HbA1c) ≤10% * Patients who are intravitreal (IVT) treatment-naïve in the study eye * Diabetic macular edema (DME) defined as macular thickening by spectral-domain optical coherence tomography (SD-OCT) involving the center of the macula. This inclusion criterion is to be assessed by the central reading center (CRC). * Decreased visual acuity (VA) attributable primarily to DME * Clear ocular media and adequate pupillary dilation to allow acquisition of good quality retinal images to confirm diagnosis Exclusion Criteria: * Currently untreated diabetes mellitus or previously untreated patients who initiated oral or injectable anti-diabetic medication within 3 months prior to Day 1 * Any known hypersensitivity to any of the components in the faricimab injection, dilating eye drops, or any of the anesthetics and antimicrobial preparations used by the patient during the study * Any major illness or major surgical procedure within 1 month before the Day 1. One re-screening for this criterion is permitted * History of other diseases, other non-diabetic metabolic dysfunction, physical examination finding, historical or current clinical laboratory finding giving reasonable suspicion of a condition that contraindicates the use of the faricimab or that might affect interpretation of the results of the study or renders the patient at high-risk for treatment complications, in the opinion of the Investigator * Active cancer within the past 12 months prior to Day 1 except for appropriately treated carcinoma in situ of the cervix, non-melanoma skin carcinoma, and prostate cancer with a Gleason score of ≤6 and a stable prostate-specific antigen for \>12 months * Stroke or myocardial infarction within 12 months prior to the Day 1. One re-screening for this criterion is permitted * Any febrile illness within 1 week prior to Day 1. One re-screening for this criterion is permitted * Pregnant or breastfeeding, or intending to become pregnant during the study or within 3 months after the final dose of faricimab * Renal failure requiring renal transplant, hemodialysis, or peritoneal dialysis within 6 months prior to Day 1 or anticipated to require hemodialysis or peritoneal dialysis at any time during the study * Any condition resulting in a compromised immune system that is likely to impact the aqueous humor (AH) inflammatory biomarkers. * Patients who are currently enrolled in or have participated in any other clinical study involving an investigational product or device, or in any other type of medical research, within 3 months or 5 half-lives prior to Day 1 and up to completion of the current study * Substance abuse occurring within 12 months prior to screening, in the Investigator's judgment * Use of systemic immunomodulatory treatments within 6 months or 5 half-lives prior to Day 1 * Use of any systemic corticosteroids (including inhaled corticosteroids from inhalers used regularly, e.g., pulmonary disease, asthma, or seasonal allergy) within 1 month prior to Day 1 * Any prior or concomitant systemic anti-VEGF treatment within 6 months or 5 half-lives prior to Day 1 * Use of systemic medications known to be toxic to the lens, retina or optic nerve used during the 6-month period or 5 half-lives prior to Day 1 or likely need to be used * Received a blood transfusion within 3 months prior to the screening visit * Received any treatment that leads to immunosuppression within 6 months or 5 half-lives prior to Day 1 Ocular Exclusion Criteria for Study Eye: * High-risk PDR. This exclusion criterion is to be assessed by the CRC * Any history of or ongoing rubeosis iridis * Any panretinal photocoagulation or macular laser photocoagulation treatment received in the study eye prior to the screening visit or expected to be received between the screening visit and Day 1 * Any history of treatment with anti-VEGF or any periocular or IVT corticosteroids in the study eye and no such treatment planned for the time between screening and Day 1 * Any treatment for dry eye disease in the last month prior to Day 1. Lubricating eye drops and ointments are permitted. * Any treatment with anti-inflammatory eye drops within 1 month prior to Day 1 * Any intraocular surgery within 3 months prior to Day 1 or any planned surgery during the study * Any glaucoma surgery/laser procedure involving the iris, trabecular meshwork, or ciliary body prior to the screening visit. Only iris surgery/laser might be allowed if they occurred more than 6 months prior to Day 1. * History of vitreoretinal surgery/pars plana vitrectomy, corneal transplant, or radiotherapy * Any active or suspected ocular or periocular infections on Day 1 * Any presence of active intraocular inflammation on Day 1 or any history of intraocular inflammation * Any history of idiopathic, infectious, or noninfectious uveitis * Any current or history of ocular disease other than DME that may confound assessment of the macula or affect central vision * Any current ocular condition or other causes of visual impairment for which, in the opinion of the Investigator, VA loss would not improve from resolution of macular edema Ocular Exclusion Criteria for Fellow Eye: * Patient is currently receiving treatment with brolucizumab or bevacizumab in the non-study eye and is unwilling to switch to a protocol allowed non-study eye treatment during the study * Any previous treatment with Iluvien® or Retisert® in the non-study eye * Non-functioning non-study eye