Treprostinil for pulmonary hypertension

Treprostinil is a stable, long-acting prostacyclin analogue which can be administered as a continuous subcutaneous infusion using a portable miniature delivery system. Subcutaneous treprostinil has been shown in a large multicenter randomized controlled trial to improve exercise capacity, clinical state, functional class, pulmonary hemodynamics, and quality of life in patients with pulmonary arterial hypertension, an uncommon disease of poor prognosis. Side effects include facial flush, headache, jaw pain, abdominal cramping, and diarrhea, all typical of prostacyclin, and manageable by symptom-directed dose adjustments, and infusion site pain which may make further treatment impossible in 7%–10% of the patients. Long-term survival in pulmonary arterial hypertension patients treated with subcutaneous treprostinil is similar to that reported with intravenous epoprostenol. There are uncontrolled data suggesting efficacy of subcutaneous treprostinil in chronic thromboembolic pulmonary hypertension. Treprostinil can also be administered intravenously, although increased doses, up to 2–3 times those given subcutaneously, appear to be needed to obtain the same efficacy. Preliminary results of a randomized controlled trial of inhaled treprostinil on top of bosentan and sildenafil therapies have shown significance on the primary endpoint, which was exercise capacity as assessed by the distance walked in 6 minutes. Trials of oral formulations of treprostinil have been initiated.