Merck’s $3B Eye Drug Hits Primary Goal but Raises Safety Concerns

Key points

• Merck’s Brunello trial confirmed that both doses of remigromig were non-inferior to ranibizumab on the primary endpoint of best-corrected visual acuity at Week 52.
• The trial identified higher rates of proliferative diabetic retinopathy, vitreous hemorrhage, and treatment discontinuations due to adverse events in the remigromig group compared to the ranibizumab group.
• Merck acquired remigromig and the bispecific MK-8748 from EyeBio in 2024 for $1.3 billion upfront, with up to $1.7 billion in additional milestones, totaling a potential $3 billion deal.
• Merck Research Laboratories President Dean Li stated that 30% to 40% of patients do not respond or stop responding to existing VEGF drugs, suggesting a market for non-VEGF pathway treatments.
• A second phase 2b/3 trial for remigromig in DME is currently ongoing and is scheduled to reach primary completion in March 2027.

Background

Merck’s acquisition of EyeBio’s assets in 2024 was a strategic move to expand its ophthalmology portfolio and mitigate the impact of Keytruda’s loss of exclusivity. The company is developing multiple therapies, including a Tie2xVEGF bispecific, to address unmet needs in eye diseases. The Brunello trial results provide early evidence for remigromig’s efficacy but highlight safety issues that require further investigation. The broader context involves the competitive landscape of DME treatments, where VEGF inhibitors like Lucentis, Eylea, and Vabysmo dominate, but a subset of patients may benefit from alternative mechanisms of action.

Why it matters

The success of remigromig in meeting its primary endpoint validates Merck’s strategy of diversifying its pipeline beyond oncology and into ophthalmology. However, the safety signals raise questions about the drug’s commercial viability and regulatory approval. If Merck can address the adverse event concerns, remigromig could offer a new option for the 30% to 40% of DME patients who do not respond to current VEGF inhibitors. This could strengthen Merck’s position in the eye care market and provide a new growth engine as Keytruda faces increased competition. The outcome of the ongoing trial and regulatory discussions will be critical in determining the drug’s future.

What to watch

Merck will present the Brunello trial data at the American Academy of Ophthalmology Annual Meeting next month. The company is also planning to discuss the findings with regulatory authorities. Further analyses are underway to characterize the safety findings, particularly the higher rates of adverse events observed in the trial. The second phase 2b/3 trial for remigromig in DME is expected to reach primary completion in March 2027, which will provide additional data on the drug’s efficacy and safety profile.