Actelion lung drug shows promise in small study

An experimental drug being developed by Actelion Ltd for a serious lung disorder significantly eased resistance to blood pumping through arteries around the lungs, according to data from a small, mid-stage clinical trial presented on Monday. The Swiss drugmaker is developing selexipag to treat pulmonary arterial hypertension, or PAH, a life-threatening condition in which abnormally high blood pressure in the arteries between the heart and lungs severely compromises the function of both organs. Patients in the 43-subject trial who received selexipag on top of other treatments had a 30.3 per cent reduction in pulmonary vascular resistance (PVR) after 17 weeks -- the main goal of the trial - compared with those who received a placebo in addition to their regular medicine, researchers said. The result was deemed to be highly statistically significant, researchers said. PVR is a measure of the resistance to blood flow that must be overcome for the heart to push blood through the circulatory system around the lungs. Reduction in such resistance is seen as a potential indication of clinical effectiveness as PVR tends to become more pronounced as PAH worsens. Actelion previously reported the drug met the primary goal of the Phase II trial, but full details of the data were presented for the first time at the ATS meeting. In addition to the primary goal, the study looked at the drug's ability to improve six-minute walking distance -- a standard goal in PAH studies because the disease can severely limit exercise capacity.