Danegaptide paper advances case for testing oral treatment of diabetic retinal disease

A study published September 23 in Science Translational Medicine brings together laboratory research and early human findings for danegaptide, an investigational oral treatment for diabetic retinal disease. The work supports further testing of a medicine intended to protect small blood vessels in the retina, while leaving its ability to preserve patients’ vision unresolved.

Researchers at Trinity College Dublin and Breye Therapeutics examined the drug in experimental disease models and a phase 1b study involving 24 patients with nonproliferative diabetic retinopathy and mild center-involved macular edema. This combination of retinal blood-vessel damage and swelling can threaten sight. An effective oral treatment could eventually offer a less burdensome approach to protecting visual function, but the current evidence remains preliminary.

### What is new—and what was reported earlier

The September paper is a new publication of a development program whose human findings have already been publicly discussed. Breye announced completion of the phase 1b trial in June 2025, and clinical data were presented at the Angiogenesis, Exudation and Degeneration symposium on February 7, 2026.

Trinity highlighted the published research on September 24. The news is therefore the combined scientific report and its supporting biological evidence, rather than a newly completed clinical trial or a regulatory decision.

That distinction matters because publication adds scientific context without changing the study’s fundamental limits. A small early trial cannot establish the long-term benefits required of a preventive treatment for a chronic disease.

### Testing the retinal barrier

The experimental work focused on the inner blood-retina barrier, which helps regulate movement between retinal blood vessels and surrounding tissue. Disruption of this barrier allows leakage and contributes to swelling.

The paper’s abstract describes danegaptide as a gap-junction modifier acting through connexin-43, a protein involved in communication between cells. Experiments in human retinal microvascular endothelial cells also examined how the drug interacts with signaling associated with vascular endothelial growth factor, or VEGF.

In preclinical disease models, the researchers reported reduced retinal vascular leakage and improved barrier function. These findings provide a biological rationale for clinical testing. They do not establish that the same effects will reliably prevent visual impairment in people.

### A safety study with exploratory signals

The human trial was an open-label, dose-escalation study. Its principal aims were to assess safety, tolerability and how the body handles the drug, while looking for early biological activity. Participants and researchers knew which treatment was being administered; there was no randomized comparison group to establish efficacy.

The UK Health Research Authority’s study record describes a four-week treatment period followed by a short follow-up. Breye reported retinal-imaging changes consistent with reduced leakage and improvements in anatomical measures. The published abstract reports no serious adverse events attributed to oral danegaptide among the 24 participants.

Those observations support continued investigation, but neither finding resolves the central clinical questions. Short exposure in a small group cannot exclude uncommon or delayed harms. Imaging improvements also cannot, by themselves, demonstrate durable preservation of sight, reduced need for other treatment, or better daily functioning.

### What larger trials must establish

A September 23 announcement carried by investor Sound Bioventures said Breye plans a randomized phase 2 proof-of-concept trial beginning in 2027. That remains a development plan, with no results available from that proposed study.

For the program to establish practical value, controlled research will need to determine whether anatomical changes translate into meaningful, lasting benefit and whether safety remains acceptable with longer exposure. The research was funded by Breye, according to Trinity, making independent confirmation valuable.

Preserving vision is directly relevant to maintaining function and independence with chronic disease. This paper advances a testable treatment strategy toward that goal; it does not yet establish an oral way to prevent diabetic sight loss.