Open Label Treprostinil Raynaud's Study

30 patients with symptomatic primary or secondary Raynaud's phenomenon (RP) resistant to standard vasodilatory therapy will be enrolled. Prior to treatment, subjects will record each day for 42 days the number of RP attacks as well as the duration of each RP attack, considered to be baseline data. After the 6-week baseline run in, all subjects will receive oral treprostinil sustained release tablets. Dose escalations can occur every 48 hours in 0.125 mg increments. Subjects will be titrated as tolerated to a goal dose of 3mg three times daily over a 6-week period. Titration can be done as quickly as tolerated. Once at goal dose subjects will enter the 26-week treatment phase. Throughout the study (6-week titration - 26-week treatment phase) subjects will record each day the number of RP attacks.