Primary endpoint
Based on FAS, in the primary endpoint analysis, the missing data will be imputed by carried forward by the last observation value respectively. In the intergroup comparison in step one, the least square mean of VAS change was 31.21 mm in the 5 μg nalfurafine group, and 19.84 mm in the placebo group. The difference of 11.37 mm between two groups is greater than 4.13 mm, the original hypothesis 50% effect of the Japanese phase III clinical trial, with a significant difference (And then in step two, the least square mean of VAS change was 28.40 mm in the 2.5 μg nalfurafine group, and 19.59 mm the placebo group. The difference of mean VAS decrease between two groups was 8.81 mm, though no significant difference (So as to PPS, the least square mean of VAS change in the 5 μg nalfurafine group was 32.1 mm, and in the placebo group was 19.82 mm. The difference of 12.28 mm between two groups was statistically significant (