In the dose-increasing part, a multicenter, dose-increasing, randomized, double-blind, placebo-parallel control design was adopted. Subjects were enrolled into different dose groups in sequence according to the inclusion sequence, and each group was scheduled to give the drug for 8 weeks.Subjects in each group were observed for 4 weeks after administration. When the number of ≥2 grade drug-related adverse events (cases) was less than 50%, subjects in the next group could be enrolled.Otherwise, IDMC will decide whether to continue the next set of tests.Subjects in each group were randomly assigned to receive either Jaktinib cream (6 cases) or placebo (2 cases) in a ratio of 3 to 1.A total of 32 subjects are expected to be enrolled in 6 centers.~The dose expansion was a multicenter, randomized, double-blind, placebo-parallel control design in which subjects were randomly assigned to 3 groups (1 placebo group and 2 experimental drugs group).It is estimated that a total of 60 subjects will be enrolled in about 15 centers. This part is divided into two stages.Stage 2 test (9 ~ 16 weeks) : Extension test.
This study includes a dose escalation part and a dose extension part.