EXPD-101

EXPD-101 (also known as FXS7553 and XH-S004) is a potent, oral, once-daily small molecule inhibitor of dipeptidyl peptidase-1 (DPP1), also known as cathepsin C. Developed by Expedition Therapeutics, Inc., it is primarily being investigated for the treatment of chronic obstructive pulmonary disease (COPD), specifically non-type 2 COPD with chronic bronchitis. DPP1 is a lysosomal cysteine protease responsible for the N-terminal activation of neutrophil serine proteases (NSPs), including neutrophil elastase, proteinase 3, and cathepsin G, during neutrophil maturation in the bone marrow. By selectively blocking DPP1, EXPD-101 prevents the activation of these pro-inflammatory enzymes, thereby reducing neutrophilic inflammation, mucus hypersecretion, and airway remodeling without impairing neutrophil host defense mechanisms. The drug was originally developed by Fosun Pharma and is currently being evaluated in the Phase 2 Navigator study as an add-on therapy for COPD.