Merck Eye Drug Meets Primary Trial Goal but Shows Higher Side Effects

Merck & Co., Inc. (NYSE:MRK) announced that its experimental eye drug, remigromig, met the primary objective of a late-stage clinical trial for patients with diabetic macular edema. In the 984-patient trial, patients receiving injections of remigromig showed vision gains of 9.1 letters for the lower dose and 8.7 letters for the higher dose after one year, compared to 11.8 letters for the standard treatment ranibizumab. The trial established non-inferiority to ranibizumab, though remigromig was not superior on secondary measures.

However, the trial revealed safety concerns. Proliferative diabetic retinopathy, a complication involving abnormal blood vessel growth in the eye, occurred in 6.7% of lower-dose patients and 6.1% of higher-dose patients, compared to 0.9% for ranibizumab. Patient discontinuation due to side effects was also higher, reaching up to 4.9% for remigromig compared to 0.9% for ranibizumab. While remigromig utilizes a new mechanism that activates the Wnt pathway to reinforce blood vessel barriers in the retina, these safety findings may present challenges for regulatory approval.

Merck plans to discuss the trial results with regulatory agencies while advancing its ongoing late-stage BAROLO study in diabetic macular edema. The company is also evaluating remigromig for wet age-related macular degeneration and blocked retinal veins, while testing another candidate, MK-8748. Future trial data and safety reviews will clarify whether remigromig can successfully enter the market.