Longer-term bosentan therapy improves functional capacity in Eisenmenger syndrome: results of the BREATHE-5 open-label extension study

Int J Cardiol. 2008 Jun 23;127(1):27-32. doi: 10.1016/j.ijcard.2007.04.078. Epub 2007 Jul 20.


Background: Bosentan, an oral endothelin ET(A)/ET(B) receptor antagonist, improves hemodynamics and exercise capacity in patients with Eisenmenger syndrome but longer-term effects are unknown. This study investigated the efficacy and safety of bosentan up to 40 weeks in these patients.

Methods: Following the 16-week, double blind, placebo-controlled BREATHE-5 study of bosentan in patients with Eisenmenger syndrome, an open-label extension (OLE) was performed. Patients who completed BREATHE-5 received bosentan for an additional 24 weeks (62.5 mg b.i.d. for 4 weeks, then 125 mg b.i.d.) and were analyzed in two groups; ex-placebo and ex-bosentan, according to BREATHE-5 treatment.

Results: Thirty-seven patients with Eisenmenger syndrome who participated in BREATHE-5 were included in the OLE. At week 24, the 6-minute walk distance (mean+/-SE) increased from OLE baseline for the ex-placebo (+33.2+/-23.9 m) and ex-bosentan group (+6.7+/-10.0 m). The overall improvement from baseline of BREATHE-5 was +61.3+/-8.1 m (95% confidence interval: [44.7, 78.0]) for the ex-bosentan group. WHO functional class was improved in both groups. Bosentan did not reduce systemic arterial blood oxygen saturation; safety profile was comparable to previous trials.

Conclusions: In conclusion, these longer follow-up data support the efficacy and safety profile reported in the preceding BREATHE-5 study of bosentan treatment of Eisenmenger syndrome, challenging the notion that pulmonary vascular disease and severe functional impairment in these patients are not amenable to therapy.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antihypertensive Agents / administration & dosage*
  • Bosentan
  • Double-Blind Method
  • Drug Administration Schedule
  • Eisenmenger Complex / drug therapy*
  • Eisenmenger Complex / physiopathology*
  • Exercise Tolerance*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Sulfonamides / administration & dosage*
  • Treatment Outcome
  • Vascular Resistance / drug effects


  • Antihypertensive Agents
  • Sulfonamides
  • Bosentan