Merck’s Eye Drug Succeeds in Late-Stage Trial, but Safety Concerns Emerge

Merck reported efficacy for a drug candidate to treat diabetic macular edema in a late-stage trial, while also disclosing some safety concerns.

Merck & Co. said on the 24th, according to BioPharma Dive, that its investigational drug remigromig demonstrated vision improvement in a late-stage trial. However, the company added that it is conducting further analysis after some adverse events occurred at higher rates in patients who received the drug.

In the late-stage BRUNELLO trial, remigromig met the noninferiority criterion for visual acuity compared with Roche’s Lucentis. However, rates of proliferative diabetic retinopathy, intraocular bleeding and treatment discontinuation were higher in the remigromig group.

Merck acquired the drug two years ago when it bought privately held iBio for $1.3 billion. The treatment, then known as Restoret, had already produced positive results in early-stage trials involving patients with diabetic macular edema and wet age-related macular degeneration.

Remigromig is a new-class injectable designed to restore the blood-retinal barrier. Merck has expanded its ophthalmology pipeline as it prepares for the patent expiration of its blockbuster cancer drug Keytruda, with a goal of reaching $70 billion in annual sales in the 2030s.

After the trial results were announced, Merck shares rose just 1% early in the session, while shares of Surrozen, which is developing a treatment targeting a similar Wnt signaling pathway, doubled.

Trung Huynh, an analyst at RBC Capital Markets, called the results “mixed” in a client note. The efficacy results are encouraging, he wrote, but “the newly disclosed safety information raises concerns.”

Umer Raffat, an analyst at Evercore ISI, was relatively less concerned. He noted that one-off vitreous hemorrhages have also been observed in trials of other ophthalmic drugs, and said, “This disclosure is typical of Merck’s conservative approach.”

Merck did not disclose detailed data that day. Full results from the first year of the trial are scheduled to be presented at a medical meeting on Oct. 10. Researchers are continuing to follow patients receiving individualized treatment in the second year.

Merck is also evaluating remigromig in a second pivotal trial for diabetic macular edema and in two phase 2 trials for other eye diseases. MK-8748, another ophthalmic drug acquired from iBio, has also entered late-stage trials.