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Efficacy and safety of intravitreal MK-8748 versus aflibercept in adults with diabetic macular edema

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The trial focuses on diabetic macular edema, a condition where fluid builds up in the central part of the retina in people with diabetes, leading to blurred vision. Participants will receive an eye injection (the medication is given intravitreal) of either the experimental drug MK-8748 or the approved drug aflibercept. The purpose of the study is to assess the efficacy of MK-8748 compared with aflibercept in participants with diabetic macular edema.

During the study, participants will be randomly assigned to one of the treatment groups and will receive injections at scheduled visits over roughly one year. Vision will be checked using a test called Best-Corrected Visual Acuity, which measures how clearly a person can see when wearing their usual glasses or contacts, and results are recorded as ETDRS letters, a standard eye‑chart scoring system. The trial will compare the average change in these vision scores from the start of the study to the end of the first year, while monitoring safety throughout the period.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Randomization and Treatment Assignment

    After joining the study, you will be randomly assigned to receive either the test medication MK-8748 or the comparator medication aflibercept (2 mg).

    The assignment is concealed, meaning neither you nor the investigators will know which medication you receive during the trial.

  2. Step 2

    Baseline Examination

    A comprehensive eye examination is performed, including measurement of Best‑Corrected Visual Acuity (BCVA) using the Early Treatment Diabetic Retinopathy Study (ETDRS) letter chart.

    Your medical history, current eye condition, and any other relevant information are recorded before the first injection.

  3. Step 3

    First Intravitreal Injection

    You receive an intravitreal injection (an injection directly into the eye).

    If assigned to the comparator group, the injection contains aflibercept at a dose of 2 mg.

    If assigned to the test group, the injection contains MK‑8748 in a solution for injection; the exact concentration is defined by the study protocol.

  4. Step 4

    Scheduled Follow‑Up Visits and Additional Injections

    You attend regular follow‑up visits according to the study schedule.

    At each visit, a repeat intravitreal injection may be administered, following the same medication and dose as the initial injection.

    During these visits, the study team checks your eye health, records any side effects, and measures visual acuity.

  5. Step 5

    Mid‑Year Visual Acuity Assessments

    At approximately week 48 and again at week 52, your Best‑Corrected Visual Acuity (BCVA) is measured using the ETDRS letter chart.

    These two measurements are averaged to determine the primary outcome of the study.

  6. Step 6

    Final Study Visit and Safety Evaluation

    After the week 52 assessment, you complete a final study visit where safety and efficacy data are collected.

    Any remaining study medication is discontinued, and you receive information about post‑study care.

Who can join the trial?

6 criteria

  • Must have Type 1 or Type 2 diabetes (a condition where the body cannot properly control blood sugar).
  • Must have a hemoglobin A1c (HbA1c) level of 12% or less (a blood test that shows average blood sugar over the past few months).
  • Must have reduced vision in the eye being studied that the doctor believes is mainly caused by diabetic macular edema (DME) (swelling in the part of the retina responsible for sharp vision).
  • If you have never been treated for DME before (treatment‑naïve), the swelling must have been diagnosed within the past 9 months before the screening visit.
  • If you have received treatment for DME before, the first treatment must have been given no more than 3 years before the screening visit.
  • Must be an adult (male or female) who meets the other criteria listed above.

Who cannot join the trial?

9 criteria

  • Cannot have kidney failure that needs a transplant, dialysis (blood‑cleaning treatments called hemodialysis or peritoneal dialysis), or is expected to need dialysis at any time during the study.
  • Cannot have had a stroke (sudden loss of blood flow to the brain) or a heart attack within the 180 days (about six months) before the first study dose.
  • Cannot have newly diagnosed or previously untreated diabetes that started oral pills or injectable medication within 3 months before the first study dose.
  • Cannot have had cataract surgery (removal of a cloudy lens) or minimally invasive glaucoma surgery in the study eye within 90 days of screening.
  • Cannot have any treatment for cataract‑surgery complications using steroids or a YAG laser capsulotomy (laser procedure to clear the lens capsule) in the study eye within 90 days of screening.
  • Cannot have advanced or uncontrolled glaucoma (damage to the optic nerve that can lead to vision loss) in the study eye.
  • Cannot have any history of retinal detachment (separation of the retina from its back surface) or surgery to fix a retinal detachment in the study eye.
  • Cannot have any active retinal disease other than diabetic macular edema/diabetic retinopathy in the study eye.
  • Cannot have uncontrolled blood pressure at the screening visit.
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Investigated drugs

  • Aflibercept

    is a medicine that is injected into the eye to help treat swelling in the retina caused by diabetes. It works by blocking a protein called VEGF that makes blood vessels grow and leak, which can lead to vision problems. In this study, it is used as the standard treatment to compare against the new drug.

  • MK-8748

    is an experimental medicine that is also given by injection. It is a specially designed antibody that blocks two important signals—one called angiopoietin‑1 receptor and another called VEGF‑A—that contribute to abnormal blood vessel growth and leakage in the eye. The trial is testing whether this new approach can improve vision better than the standard treatment.

What is already known about the treatment

  • Aflibercept

    It is given as a small injection into the eye (intravitreal) at a dose of 2 mg. The drug is already approved and widely used for eye swelling caused by diabetes, age‑related macular degeneration, and vein blockage. It works by attaching to proteins that tell blood vessels to grow, stopping them from leaking fluid into the retina. Aflibercept belongs to the anti‑VEGF (vascular endothelial growth factor) class of medicines.

  • MK‑8748

    This experimental medicine is supplied as a clear solution for injection that is placed directly into the eye. It is still being studied in Phase 3 trials and is not yet approved for general use. The drug is designed to block two signals, one from VEGF‑A and another from the angiopoietin‑1 receptor, which together reduce abnormal blood‑vessel growth and fluid leakage in diabetic eye disease. MK‑8748 is classified as a dual‑target anti‑angiogenic biologic (a monoclonal antibody‑based therapy).

Investigated diseases

Diabetic macular edema - Diabetic macular edema is swelling in the central part of the retina caused by fluid leakage from damaged blood vessels in people with diabetes. High blood sugar damages these tiny vessels, making them more permeable. Fluid builds up in the macula, thickening it and leading to blurred or distorted vision. Over time, the swelling can spread, further reducing visual clarity. The condition often develops gradually and can affect one or both eyes.
Trial detailsLast updated 13 Nov 2026
Age18+ yearsPhasePhase IIITrial ID2026-526787-20-00Protocol codeMK-8748-005Estimated enrolment1 022 patientsSponsorMerck Sharp & Dohme LLC

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