Beyond VEGF: Therini's New Attack on Diabetic Eye Disease

SACRAMENTO, CA – May 27, 2026 – Therini Bio, a clinical-stage biotechnology company, has initiated a new chapter in the fight against diabetic eye disease, announcing today that it has dosed the first patients in a Phase 1b trial for its novel therapy, THN391. The trial targets Diabetic Macular Edema (DME), a leading cause of vision loss in working-age adults, with a unique approach that looks beyond the current standard of care to address the underlying inflammation that drives the disease.

This milestone not only marks a critical step for THN391 but also sheds light on the company's broader strategy to reshape retinal disease treatment, which includes the development of a next-generation bispecific antibody, THN622. With strong backing from a syndicate of top-tier life sciences investors, Therini is positioning itself to tackle the complex neuroinflammatory processes that have long challenged ophthalmologists and their patients.

A Novel Target Beyond Standard Care

For years, the treatment of DME has been dominated by therapies that inhibit vascular endothelial growth factor (VEGF), a protein that promotes the growth of leaky, abnormal blood vessels in the retina. While anti-VEGF drugs like Eylea and Lucentis have been revolutionary, a significant number of patients have a suboptimal response, and the treatment burden of frequent eye injections remains a major challenge. This has fueled a search for new therapeutic targets that address other aspects of the disease's complex pathology.

Therini Bio is focused on one such target: fibrin. In DME, the breakdown of the blood-retinal barrier allows blood components, including the protein fibrinogen, to leak into retinal tissue. There, it is converted into insoluble fibrin deposits. While fibrin is essential for blood clotting, Therini’s foundational research revealed that these deposits have a dark side. When fibrin forms, it exposes a previously hidden segment, or 'inflammatory epitope,' that acts as a powerful trigger for chronic inflammation. This epitope binds to receptors on the surface of immune cells like microglia, activating them and unleashing a cascade of neuroinflammation that contributes directly to retinal cell damage and vision loss.

THN391 is a first-in-class monoclonal antibody meticulously designed to neutralize this inflammatory activity. It selectively binds to and blocks fibrin's inflammatory epitope, effectively halting the inflammatory cascade at its source. Crucially, its design allows it to perform this function without interfering with fibrin's vital role in coagulation, a key safety feature. Preclinical research, published in the Journal of Neuroinflammation, demonstrated that THN391 was as effective as anti-VEGF therapies in reducing vascular leakage in disease models, while also providing protection against neuronal degeneration.

The Clinical Path and Competitive Landscape

The ongoing Phase 1b trial is a multiple ascending dose study designed to rigorously evaluate the safety and preliminary efficacy of THN391. Patients enrolled in the trial will receive three monthly intravitreal injections across three different dose cohorts. Investigators will monitor not only for safety but also for signs of biological activity, measuring changes in retinal thickness, improvements in visual acuity, and other exploratory biomarkers. The company expects to have initial data from this study in the fourth quarter of 2026.

“The dosing of the first cohort of patients in our THN391 trial represents a significant milestone for Therini Bio,” said Joel Naor, M.D., M.B.A., MSc., Chief Medical Officer of Ophthalmology at Therini Bio. Dr. Naor, a veteran of retinal therapeutic development with leadership experience at companies like Kodiak Sciences, Allergan, and Opthea, added, “By targeting fibrin-driven inflammation, THN391 has the potential to enhance retinal health, improve treatment outcomes, and preserve vision in patients with DME.”

If successful, THN391 could carve out a significant place in the DME treatment landscape. It could serve as a powerful new monotherapy for the many patients who do not respond adequately to anti-VEGF treatments, or it could be used as an adjunctive therapy, combining its anti-inflammatory action with the anti-leakage effects of VEGF blockers to achieve superior outcomes.

The Next Frontier: A Bispecific Antibody for Retinal Disease

While THN391 progresses through the clinic, Therini is already looking ahead to what it hopes will be the next standard of care. The company is actively developing THN622, a bispecific antibody that combines two distinct mechanisms of action in a single molecule. This next-generation therapeutic is engineered to simultaneously block both the inflammatory fibrin epitope targeted by THN391 and the VEGF pathway targeted by current standard-of-care drugs.

The rationale behind this dual-action approach is to provide a more comprehensive attack on DME's pathology. By addressing both vascular leakage and neuroinflammation, THN622 has the potential to deliver superior efficacy and durability compared to single-target therapies. A more complete blockade of the disease process could lead to better visual outcomes, longer intervals between injections, and a reduced treatment burden for patients. Furthermore, by inhibiting the fibrin deposition that contributes to scarring, THN622 may also prevent fibrosis, a dreaded complication that can cause irreversible vision loss.

This strategy aligns with a broader trend in medicine toward combination therapies for complex, multifactorial diseases. Should THN622 succeed, it could simplify treatment regimens while offering a more robust and lasting effect, potentially establishing a new benchmark for how neurodegenerative retinal conditions are managed.

Investor Confidence and Strategic Vision

Therini Bio's ambitious pipeline is fueled by a formidable syndicate of investors, including the Alzheimer’s Drug Discovery Foundation, Eli Lilly and Company, Sanofi Ventures, and the venture arm of Merck & Co., Inc., among others. This strong financial backing serves as a powerful validation of the company's novel scientific platform, which also includes a program for THN391 in Alzheimer's disease, another condition where vascular-mediated inflammation is believed to play a critical role.

The company's focused pursuit of fibrin-mediated inflammation as a core therapeutic target represents a calculated and strategic bet on a new frontier of medicine. With the THN391 trial now underway and the promise of the bispecific THN622 on the horizon, the coming months will be pivotal. The initial data expected later this year will provide the first clinical glimpse into whether targeting fibrin can truly change the course of diabetic eye disease and offer new hope to millions of patients worldwide.