Abstract: 【Abstract】 Objective To explore the prolonged therapeutic regimen for patients with plaque psoriasis, who showed a positive response to 4-week treatment with tazarotene/betamethasone dipropionate cream, but were not completely cured. Methods A multicenter, randomized, open-labelled, parallel-controlled clinical study was conducted. A total of 232 patients with plaque psoriasis were collected, who showed a positive response to previous 4-week treatment with 0.05%/0.05% tazarotene/betamethasone dipropionate cream, but were not completely cured with the psoriasis area and severity index ［PASI］ improvement rate being 50% - 90%. At week 5, they were randomly and equally divided into 2 groups: test group receiving treatment with 0.05%/0.05% tazarotene/betamethasone dipropionate cream once a day, and control group receiving a sequential regimen of 0.05% tazarotene gel on weekdays once a day followed by 0.05%/0.05% tazarotene/betamethasone dipropionate cream on weekends once a day. After 2- and 4-week prolonged treatment, the efficacy and safety of the 2 therapeutic regimens were evaluated and compared. Measurement data were compared between 2 groups by using covariance analysis or t test, and enumeration data were compared by using chi-square test. Results From the 5th to the 8th week, 200 out of the 232 patients completed the treatment. Data collected from 110 patients in the test group and 112 in the control group were enrolled into the full analysis set, and those from both 113 patients in the test group and control group were enrolled into safety analysis set. After consecutive 6- and 8-week treatment, the decline rates of the PASI score were 73.05% ± 16.69% and 78.46% ± 15.40% respectively in the test group, which were significantly higher than those in the control group （66.73% ± 21.77%, 67.02% ± 34.19%, respectively, both P < 0.05）. After 6-week treatment, the proportion of subjects who achieved PASI90 was significantly higher in the test group （14 cases, 12.7%） than in the control group （5 cases, 4.5%, χ2 = 4.842, P = 0.028）; After 8-week treatment, the proportions of subjects who achieved PASI75 and PASI90 （61.8%, 23.6%, respectively） were significantly higher in the test group than in the control group （48.2%, 12.5%, respectively, both P < 0.05）. During the consecutive 8-week treatment, there was no significant difference in the incidence rate of adverse reactions between the test group （15.0%） and control group （23.9%, χ2 = 2.822, P = 0.093）. Conclusion For patients who showed a positive response to 4-week treatment with 0.05%/0.05% tazarotene/betamethasone dipropionate cream, but were not completely cured, the continuous use of 0.05%/0.05% tazarotene/betamethasone dipropionate cream for 4 weeks is a superior therapeutic regimen compared with the sequential regimen of 0.05% tazarotene gel followed by 0.05%/0.05% tazarotene/betamethasone dipropionate cream.

Key words: Psoriasis, Randomized controlled trial, Retinoids, Tazarotene/betamethasone dipropionate cream