Trial Outcomes & Findings for Clinical Study to Evaluate the Effects of Macitentan on Exercise Capacity in Subjects With Eisenmenger Syndrome (NCT NCT01743001)

The study was conducted at 71 sites in 26 countries (geographical regions: Asia-Pacific, Eastern Europe, Latin America, North America, Western Europe including Israel and Turkey, and South Africa), of which 55 sites in 21 countries randomized subjects.

The screening period lasted a maximum of 30 days from Visit 1 up to Randomization (Visit 2). A total of 319 subjects were screened and 226 subjects were randomized to macitentan 10 mg and placebo.

Per protocol patients in WHO functional class I were excluded.

The purpose of the six minute walk is to test exercise tolerance and capacity. The test measures the distance an individual is able to walk over a total of six minutes on a hard, flat surface. The goal is for the individual to walk as far as possible in six minutes.

A shift in WHO functional classes is considered an 'improvement' when shifting to a lower class (e.g. from class III to class II) or a 'worsening' when shifting to a higher class (e.g. from class III to class IV). Definition of functional classes as follows - Class I: no symptoms with exercise or at rest. Class II: No symptoms at rest but uncomfortable and short of breath with normal activity such as climbing a flight of stairs, grocery shopping, or making the bed. Class III: May not have symptoms at rest but activities greatly limited by shortness of breath, fatigue, or near fainting (e.g. doing normal chores around the house, have to take breaks while doing activities of daily living). Class IV: Symptoms at rest and severe symptoms with any activity. Most patients also have edema in the feet and ankles as result of right heart failure.

This outcome measures the difference in the Borg dyspnea index collected at the end of the 6-minute walk test (6MWT) at Week 16 compared to baseline. The Borg dyspnea index rates the severity of dyspnea (difficult or labored breathing) on a scale from 0 ('Nothing at all') to 10 ('Very, very severe - maximal'). A decrease in the Borg dyspnea index indicates an improvement.

The SF-36 is a multi-purpose, short-form health survey with 36 questions. It yields an 8-scale profile of the functional health and well-being scores (i.e., physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional and mental health), as well as psychometrically based physical and mental health summary measures and a preference-based health utility (health rated as much better now than one year ago to much worse now than one year ago). It is a generic measure, as opposed to one that targets a specific age, disease, or treatment group. For each of the domains and scores that the SF36 measures an aggregate percentage score is produced. The percentage scores range from 0% (lowest or worst possible level of functioning) to 100% (highest or best possible level of functioning). A higher score for the individual domains and summary component scores indicates a better condition of the subject.