The 6MWT is a non-encouraged test, which measures the distance (in meters) covered by the subject during a 6-minute walk. It is performed in a 30-meters long flat corridor, where the patient is instructed to walk as far as possible, back and forth around two cones, with the permission to slow down, rest, or stop if needed.
Absolute change from baseline to Week 16 in 6MWD is measured at trough levels of inhaled treprostinil and/or selexipag. The trough level of inhaled treprostinil is defined as the last dose having been taken not less than 4 hours and not more than 48 hours prior to the 6MWT at Visit 1 (screening). The trough level of selexipag was defined as the last dose having been taken not less than 8 hours and not more than 7 days prior to the 6MWT at Visit 5 (Week 16).