Change in VAS value
Evaluating the VAS values both in the morning and evening, the daily larger VAS value was defined as the larger one of each day. And the mean larger VAS values of each day were calculated for the last seven days of the pre-observation period, and latter seven days of the treatment period. Using the mean larger VAS value for the last seven days of the pre-observation period as a baseline, the decrease in the mean VAS value from the baseline during each subsequent period was assessed as the change in the VAS value. The primary endpoint was defined as the change from the mean larger VAS value of the last seven days of the pre-observation period and the mean larger VAS value of the latter seven days of the treatment period.