Inhalation of repurposed drugs to treat pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a rare, but severe and life-threatening disease characterized by vasoconstriction and remodeling of the pulmonary arterioles, leading to progressive increase in pulmonary vascular resistance and ultimately to right-heart failure. In the last two decades, significant progress in treatment of PAH has been made, with currently 12 drugs approved for targeted therapy. Among these, the stable prostacyclin analogues iloprost and treprostinil have been repurposed for inhalation. The paper highlights the development of the two drugs emphasizing the rationale and advantages of the inhalative approach. Despite substantial advances in the specific, mainly vasodilatory PAH therapy, disease progression is mostly inevitable and mortality remains unacceptably high. Thus, introduction of new drugs targeting the cancer-like remodeling of the diseased pulmonary arteries is urgently needed. Inhalation offers pulmonary selectivity and will hopefully pioneer the repurposing of novel highly potent drugs for effective aerosol therapy of PAH.