Emerging therapies for pulmonary arterial hypertension: a review of recently completed and ongoing clinical trials

Pulmonary arterial hypertension (PAH) is a rare, progressive disorder that leads to an inexorable rise in pulmonary vascular resistance, ultimately resulting in right ventricular failure and death if left untreated. Currently available pulmonary vasoremodeling therapy has significantly improved morbidity and mortality in PAH. However, 3-year mortality in PAH is still higher than in many other cardiovascular diseases. Recent and ongoing clinical trials in PAH have evaluated five major avenues of clinical investigation: trials of combination therapy using current US FDA-approved agents; trials of new forms or new delivery systems of existing agents; trials of newly developed agents that target novel steps in existing pathways implicated in the pathogenesis of PAH; trials of agents targeting new pathways that may play a role in PAH; and stem-cell and molecular therapy for PAH. This article reviews evidence for emerging therapies for PAH based on recently completed and ongoing clinical trials.