Bosentan in Pulmonary Hypertension in Interstitial Lung Disease Treatment Study

• Purpose: High blood pressure in the lungs or pulmonary hypertension (PH) is a common complication of fibrosing (or interstitial, ILD) lung disease. When present, it is associated with markedly reduced prognosis and survival. Endothelin-1 (ET-1)is over-expressed in patients with PH and ILD, and is thought to play a role in the development of both conditions. Bosentan blocks the action of ET-1, and has been shown to be beneficial in patients with PH from an unknown cause, or related to other conditions (such as heart conditions, connective-tissue disease, and HIV). It is important to establish whether bosentan treatment also benefits patients with PH and ILD. This study addresses the effectiveness of bosentan in the context of PH and ILD. • Objective: To examine the ability of bosentan to reduce high blood pressure in the lungs in patients with fibrosing lung diseases and pulmonary hypertension. • Design: This is a multi-centre, randomised, double-blinded, placebo-controlled study looking at the effect of bosentan in patients with fibrotic lung disease and PH. • Methodology: Patients will be recruited from outpatient ILD and PH clinical services and will be consented prior to entering the study. We propose to study 48 patients over a 16 week period. Patients will be included in the study if they have fibrosing lung disease (specifically: idiopathic pulmonary fibrosis or idiopathic fibrosing non-specific pneumonitis) and have PH as determined by measurement on right heart catheter (mean pulmonary artery pressure \>=25mmHg, pulmonary capillary wedge pressure =\<15mmHg). Patients will enter a 2 week screening period during which they will have a full medical history and examination. If they have not already had clinically important investigations ( echocardiogram, cardiac MRI, overnight oximetry) within the previous 6 weeks and CT scan within the last 3 months, these will be performed. The patient will have a baseline 6 minute walk test, ECG (heart tracing), blood tests and pulmonary blood flow study (breath test) and lung function tests (breathing tests) and complete a quality of life questionnaire. The patient will then be randomised to bosentan or placebo (2:1)at the baseline visit. Patients will be followed every 4 weeks with physical examination, and blood tests. At week 16, the initial investigations (including right heart catheter, lung function, pulmonary blood flow, 6-minute walk, blood tests, echocardiogram and cardiac MRI and complete a quality of life questionnaire) will be repeated. Patients will be offered treatment with open-labelled bosentan therapy until the results of the trial become available up to a maximum of 2 years.