Therini Bio announced that the first patients have been dosed in a phase 1b clinical trial evaluating THN391, an investigational anti-fibrin monoclonal antibody for diabetic macular edema (DME). THN391 is designed to selectively block fibrin’s inflammatory epitope while preserving normal coagulation. The approach is based on evidence suggesting that breakdown of the blood-retinal barrier in DME leads to fibrin deposition, chronic inflammation, and neuroretinal damage. In a recently published preclinical study, THN391 demonstrated activity comparable to VEGF antagonists in limiting leakage from neovascular lesions.

The ongoing phase 1b study is a multiple ascending-dose trial that will enroll patients across 3 dose cohorts. Participants will receive 3 monthly intravitreal injections. Investigators will assess safety as the primary objective, while measures of biologic activity will include central subfield thickness, visual acuity, and exploratory biomarkers. Initial data are expected in late 2026.

The company also provided an update on its ophthalmology pipeline, including the selection of THN622, a bispecific fibrin/VEGF antibody, as its lead retinal candidate. According to Therini, the TNH622 program is intended to address both VEGF-mediated vascular leakage and fibrin-driven inflammation, with the goal of improving efficacy, durability, and overall treatment response in retinal vascular disease. RP