The FDA has approved treprostinil sodium injection (Remodulin, United Therapeutics Corp, Research Triangle Park, NC) as a continuous subcutaneous infusion for the treatment of pulmonary arterial hypertension (PAH) in patients with New York Heart Association (NYHA) Class II-IV symptoms to diminish symptoms associated with exercise.
The product was approved on the basis of two 12-week, multicenter, randomized, double-blind studies that compared treprostinil with placebo in 470 patients with NYHA Class II-IV PAH. Treprostinil was administered as a subcutaneous infusion using a portable pump, and the dose averaged 9.3 ng/kg per minute at week 12. The effect of the drug on the 6-minute walking distance, the primary end point of the studies, did not achieve statistical significance. Compared with placebo, however, treprostinil improved associated subjective measurements of shortness of breath during the 6-minute walk test called the Borg dyspnea score, and had a significant effect on a symptom assessment that combined walking distance with the Borg dyspnea score. Treprostinil also consistently improved measures of dyspnea and fatigue and signs and symptoms of AH.