This study investigated the long-term effects of bosentan, an oral endothelin ET(A)/ET(B) receptor antagonist, in patients with pulmonary arterial hypertension (PAH) exclusively related to connective tissue diseases (CTD).
A total of 53 patients with PAH related to connective tissue diseases (PAH-CTD) in World Health Organization (WHO) functional class III received bosentan 62.5 mg twice a day for 4 weeks and then 125 mg twice a day for 44 weeks in this open non-comparative study. Assessments at weeks 16 and 48 included WHO class, clinical worsening, quality of life (Short-Form Health Survey (SF-36) and health assessment questionnaire (HAQ) modified for scleroderma), and survival (week 48 only). Safety and tolerability were monitored throughout the study.
At week 48, WHO class improved in 27% of patients (95% CI 16-42%) and worsened in 16% (95% CI 7-29%). Kaplan-Meier estimates were 68% (95% CI 55-82%) for absence of clinical worsening and 92% (95% CI 85-100%) for survival. Overall changes in quality of life were minimal. There were no unexpected side effects observed during the study.
In most patients, bosentan was associated with improvement or stability of clinical status. The 92% estimate for survival at 48 weeks is a significant achievement in this patient population.