Kalaris Therapeutics, Inc. KLRS

We are a clinical stage biopharmaceutical company dedicated to the development and commercialization of treatments for prevalent retinal diseases with major unmet medical needs.

We are developing TH103, a novel, clinical stage anti-vascular endothelial growth factor ("VEGF") drug, specifically engineered to achieve extended intraocular retention with enhanced VEGF inhibition in patients with exudative and/or neovascular retinal diseases. TH103 is a fully humanized recombinant fusion protein, functioning as a "decoy receptor" (a VEGF trap), leveraging salient molecular properties of the human body's native, highest affinity VEGF receptor 1. In head-to-head preclinical studies, TH103 showed more anti-VEGF activity and longer duration of activity compared to aflibercept, the current market-leading anti-VEGF agent, which also functions as a decoy receptor VEGF trap but differs from TH103 in key molecular elements. In December 2025, we reported initial data from our Phase 1a single ascending dose ("SAD") trial of TH103 in treatment-naïve neovascular Age-related Macular Degeneration ("nAMD") patients that showed TH103 was generally well tolerated and exhibited improvements on functional and anatomical outcomes at 1-month post-dosing. Preliminary single dose pharmacokinetic data from the Phase 1a trial also provide evidence that TH103 may offer extended treatment durability after a standard four-dose loading regimen.