Treprostinil Combined With Tadalafil for Pulmonary Hypertension

Objectives: To test whether the combined administration of the medications treprostinil(a prostacycline therapy), and tadalafil(a PDE-5 \[ phosphodiesterase type 5\]Inhibitor therapy) is better than the administration of treprostinil alone. This treatment would be offered to newly diagnosed patients with pulmonary arterial hypertension who are on no treatment for this disease and are deemed candidates for the medication treprostinil by their physician. The combination therapy will be compared to single therapy with only treprostinil in a double-blind manner. Current therapy is to begin one treatment, either a PDE5 inhibitor or a prostacycline, depending on the severity of the patient's PAH (pulmonary arterial hypertension) disease and add additional therapies as deterioration occurs. This treatment could add two agents initially. Secondary objectives are: To improve pulmonary arterial pressures as measured through a cardiac echocardiogram, improve the subject's 6minute walk distance, delaying the time to clinical worsening, and lowering plasma BNP levels. Research Procedures: To begin the administration of both treatments at the same time. Time period is 16 weeks with a one- year follow-up. Cardiac Echocardiograms, clinic physician exams, and lab work will be followed. Subjects will be between the ages of 18 - 75.