In this issue of CHEST (see page 1383), Tapson et al3 report the results of the Oral Treprostinil for the Treatment of Pulmonary Arterial Hypertension in Patients on Background Endothelin Receptor Antagonist and/or Phosphodiesterase Type 5 Inhibitor Therapy (FREEDOM-C) Study, a randomized, placebo-controlled trial of oral treprostinil for the treatment of patients with PAH on background therapy with endothelin receptor antagonists and/or phosphodiesterase type 5 inhibitors. In this trial, 350 patients with PAH were randomized to placebo or oral treprostinil and followed over 16 weeks with the primary end point being the 6MWD. The placebo-corrected median difference in change in 6MWD over the 16 weeks was not significant at 11 m (P = .07). There was also no change in the secondary end point of time to clinical worsening. There were clear limitations of the study that likely contributed to this neutral result, including the high dropout rate (22% subjects on active drug, 14% of subjects receiving placebo), high frequency of dual, background, oral therapy (45%), and difficulty with dose titration. Did the drug fail or did the study design fail?