Potential benefit of bosentan therapy in borderline or less severe pulmonary hypertension secondary to idiopathic pulmonary fibrosis-an interim analysis of results from a prospective, single-center, randomized, parallel-group study

Background: No drugs have been approved for the treatment of patients with pulmonary hypertension (PH) secondary to idiopathic pulmonary fibrosis (IPF), particularly those with idiopathic honeycomb lung. This study was conducted to investigate the long-term efficacy and safety of bosentan for PH based on changes in prognosis and respiratory failure. Methods: IPF patients with borderline or less severe PH and completely organized honeycomb lung were randomized (1:1) to bosentan or no treatment for PH for 2 years and assessed at baseline and every 6 months for respiratory failure, activities of daily living (ADL), lung and heart functions by right cardiac catheterization, and other parameters. An interim analysis was performed, however, following detection of a significant survival benefit favoring bosentan therapy. Results: Significant differences were noted for the bosentan-treated (n = 12) vs. untreated (n = 12) groups in hospital-free survival (603.44 +/- 50.074 days vs. 358.87 +/- 68.65 days; hazard ratio [HR], 0.19; P = 0.017) and overall survival (671 days vs. 433.78 +/- 66.98 days; HR, 0.10; P = 0.0082). Again, significant improvements were noted for the bosentan-treated group from baseline to month 6 or 12 in several indices in ADL, pulmonary circulation, and %DLCO. Without requiring O-2 inhalation, bosentan was associated with no increase but a trend toward a decrease in adverse events and an improvement in respiratory status. Conclusions: Bosentan tended to improve prognosis and ADL without worsening respiratory failure in IPF patients with borderline or less severe PH and completely organized honeycomb lung alone.