The NRS is a patient related outcome (PRO) instrument, designed to quantify the intensity of worst itching experienced during a 24-hour period, and can be applied and validated either with reference to the average itch or to the absolute worst itch (WI-NRS) over that 24-hour period. WI-NRS is a set of boxes, one for each number, from 0 (no itching) to 10 (worst possible itching). Higher scores indicate worst itching experience. Responder was defined as a participant with a ≥4-point decrease in the 7-day average WI-NRS from baseline to Week 14.

Incidence of adverse events is calculated based on events observed on or after the date of first dose, where incidence is defined as the number of subjects who reported one or more events of a particular adverse event divided by the number of subjects who received at least one dose of investigational product. Overall incidence is the proportion of subjects who had one or more adverse events of any type and nature pertains to the incidence of individual events coded by MedDRA nomenclature. An additional consideration was to evaluate incidence of adverse events by dose achieved but this was not done as subjects achieved a maximum dose during the study that varied and, per protocol, dosing could be modified per the investigator, during the course of this extension to TR03. In addition, TR03EXT involved a dose titration whereas events could have been reported well before a subject achieved some partciular dose level. Consequently, such a presentation would have been impossible to discern.

The number of subjects who reported at least a 30% reduction from baseline to Week 10, expressed as a percentage of subjects in the particular arm/group who were evaluated,