Palatin presents preclinical data on PL9654 and PL9655 at ARVO

Palatin (PTN) Technologies announced new preclinical data on its melanocortin agonists PL9654 and PL9655 at the 2025 Association for Research in Vision and Ophthalmology Annual Meeting. The findings demonstrate the agents’ ability to resolve inflammation, stabilize the blood-retinal barrier, reduce VEGF signaling, and protect retinal ganglion cells, key drivers of vision loss in diabetic retinopathy. Notably, both compounds showed efficacy across multiple models and routes of administration, including topical delivery. Key Findings: Vision preservation: PL9654 and PL9655 maintained contrast vision and showed significant efficacy compared to vehicle. Inflammation control: Gene set enrichment analysis revealed downregulation of immune-related pathways in microglia and Muller glial cells for PL9654 and PL9655 compared to vehicle. Retinal protection: PL9654 reduced ischemia-reperfusion-induced retinal damage (as measured by histological scoring), similar to the melanocortin peptide alpha-MSH. Cell integrity: Microglia and Muller glial cell levels in treated animals mirrored those in healthy controls. Neuroregeneration: Topical PL9655 treatment increased rod photoreceptor levels relative to vehicle. Anti-angiogenesis: PL9654 significantly inhibited choroidal neovascularization and fibrosis. PL9655 topical treatment also showed an increase in rods compared with vehicle.