Pulmonary arterial hypertension [PAH] is a major cause of death in diffuse cutaneous Systemic Sclerosis [dcSSc] patients in functional class III with the least chances for improvement. Moreover, the unfavorable effects of pulmonary fibrosis in dcSSc threaten the mortality of these patients. This study examines the effects that bosentan monotherapy has on
Functional Class III patients with PAH related to dcSSc with pulmonary fibrosis. Conducted between 1 March 2010 to 21
August 2014 at the Scleroderma Clinic of Srinagarind Hospital, Thailand, an open-labeled study was performed on these
patients (rated as Function Class III by the WHO). During the 12 month period, they received bosentan and were then
evaluated for survival, WHO Functional Class, safety, and tolerability. Of the 10 patients enrolled, all survived. Forty
percent (40%) of patients improved from Class III to Class II by the end of month 6, and month 12. Seventy percent (70%)
of patients showed significant improvement by making steady progress in the 6 minute walk test. No serious side-effects
were detected. Bosentan can be used in dcSSc patients who suffer from WHO Functional Class III PAH.

Keywords: Pulmonary arterial hypertension, Systemic sclerosis, Bosentan, Lung fibrosis