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How long does Eylea or Eylea HD take to work?

Medically reviewed by Carmen Pope, BPharm. Last updated on Sep 1, 2023.

Official answer


Eylea and Eylea HD usually work within 3 months, with some people noticing improvements in as little as one month of treatment, depending on the condition being treated. Some conditions may take up to 6 months before a significant difference is seen. Many trials for Eylea only reported on results after 1 year of treatment and these report significant improvements in vision and the ability to read and see letters more clearly after this length of time for conditions such as Wet AMD, Diabetic macular edema, and diabetic retinopathy. Improvements in vision were maintained for the length of the trial (4 years in some instances).

For premature infants with retinopathy of prematurity (ROP), a leading cause of childhood blindness, Eylea may take up to 52 weeks to work. Two Phase 3 randomized trials FIREFLEYE (N=113) and BUTTERFLEYE (N=120) reported that approximately 80% of Eylea-treated infants achieved an absence of both active ROP and unfavorable structural outcomes after 52 weeks, which was significantly more than what would’ve been expected with placebo.

For diabetic macular edema specifically, 58% of patients had an improvement in their visual acuity measurements at 6 months compared to 6% in the control group. At one year, 80% of patients receiving Eylea improved compared to 15% in the control group. Patients in the Eylea groups gained, on average, the ability to read about two additional lines (15 more letters) on an eye chart compared with almost no change in the control group. In addition, those who received Eylea reduced the risk of continuing to a more serious stage of diabetic retinopathy.

A trial of Eylea HD for neovascular (wet) age-related macular degeneration of 48 weeks duration reported a mean change in Best Corrected Visual Acuity (BCVA) for Eylea HD of 8.8 for Eylea HD administered every 12 weeks, 7.9 for Eylea HD administered every 16 weeks, and 9.2 for Eylea 2 mg administered every 8 weeks. All dosage regimens were maintenance regimens administered following 3 initial monthly doses. Improvements in all dosing regimens were noted in as little as 4 weeks.

Related questions

  • Eylea (aflibercept). Updated Sep 1, 2022. Regeneron Pharmaceuticals, Inc.
  • Eylea (aflibercept) Injection Approved as the First Pharmacologic Treatment for Preterm Infants with Retinopathy of Prematurity (ROP) by the FDA Feb 08, 2023.
  • Eylea HD Prescribing information. Updated Aug 28, 2023.

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