Prostacyclin (PG) remains the gold standard therapy for severe pulmonary arterial hypertension (PAH). Previously, we reported the successful transitioning of PAH subjects from intravenous prostacyclin to oral bosentan (Suleman et al. Chest 2004;126:808–15). We report here the 5-year follow-up data.

In the transition study, 11 PAH subjects were successfully transitioned to oral bosentan in 12 weeks. Two subjects who subsequently developed liver function test (LFT) abnormalities were taken off bosentan and switched to another endothelin receptor antagonist. Demographics, six-minute walk distance (6MWD), WHO functional class (FC), and survival data was collected.

10 Females and 1 male ranging in age from 35 to 79 were successfully transitioned. Mean duration of illness prior to transition was 50.55±26 months. Mean duration that these subjects remained on oral therapy was 34±24 months. Mean duration that patients remained off PG was 28±21 months. In 7 of the 11 subjects (64%), PG was resumed due to clinical deterioration. One patient remained on bosentan as monotherapy, five had phosphodiesterase 5-inhibitor added. 9 Of the 11 subjects were WHO FC II post-transition and 5 of the 7 subjects at follow-up were WHO FC II (82% vs 67%). Post-transition 6MWD was 386±85 in 10 subjects and at follow-up 6MWD was 396±99 in 9 subjects (p=0.81).

In this study, patients frequently required prostanoid resumption after transition from intravenous prostanoid to oral therapy. However, in these carefully selected patients, transition to oral therapy offered prolonged stable FC and 6MWD, cost savings and substantial quality of life benefits.