Tiprelestat (Elafin) is a potent Human neutrophil elastase inhibitor. Elafin is identical to the human protein elafin with high specificity for tissue destroying and inflammation promoting proteases. The development program of Elafin is focused on the late stage development of Elafin in major surgery and early stage development in pulmonary arterial hypertension (PAH). Elafin has received orphan drug designations in the USA and the EU for esophageal cancer surgery (ECS) and PAH. Tiprelestat is in phase II clinical trials for the treatment of myocardial reperfusion injury, postoperative inflammation and in phase I clinical trial for the treatment of pulmonary arterial hypertension.