Apeptico is developing solnatide (AP301), a dry powder inhalation and an inhaled aerosol formulation of a synthetic peptide for the treatment of acute lung injury, acute respiratory distress syndrome and pulmonary oedema caused by lung infection or high altitude. The AP301 peptide mimics the lectin-like domain of TNF-α. The synthetic peptide AP301 is composed of 17 amino acids and contains an intramolecular disulfide bond between the N-terminal and the C-terminal cysteine. AP301 interacts with the endothelial sodium channel (ENaC) and activates pulmonary liquid clearance both in vitro and in animal studies. The specific interaction of AP301 with both endogenously and heterologously expressed ENaC requires precedent binding to glycosylated extracellular loop(s). Solnatide has been granted Orphan Drug Designation for “Treatment of Primary Graft Dysfunction following Lung Transplantation” and for “Treatment of Pseudohypoaldosteronism Type 1B” by the Food and Drug Administration.