Egret Therapeutics

EGT-101 is a first-in-class PD-L1-hyFc fusion protein to restore immune balance and enhance recovery after TBI. Rather than broadly suppressing immunity, it is designed to selectively reprogram the immune cells that drive secondary damage. Human correlative data in TBI patients show that PD-1+ inflammatory monocytes mobilize from bone marrow, expand after injury, and peak in circulation within 48 hours. In preclinical models, engaging PD-1 on these monocytes with its natural ligand PD-L1 reprograms them to a restorative CX3CR1+ phenotype, suppressing inflammatory signaling, reducing lesion and edema volume, and improving motor and cognitive recovery. EGT-101 is clinical-stage (TRL 6). A Phase 1 study in healthy volunteers completed with no DLTs or SAEs at doses up to 30 mg/kg, and an extended half-life of 6-9 days enables a single peripheral IV infusion to cover the entire critical secondary injury window. Because the target is measurable and druggable in peripheral blood, no CNS delivery or blood-brain barrier penetration is required - giving a wide treatment window compatible with field evacuation timelines in Role 2/3 administration. The same PD-1+ monocyte kinetics have been documented in human ischemic stroke and subarachnoid hemorrhage patients, indicating a stereotyped immune response conserved across CNS injury and possible relevance to injuries beyond the brain - SCI, musculoskeletal, and polytrauma.