Efficacy and safety of supramolecular active zinc in the treatment of scalp psoriasis: a multicentre, randomized, observed-blind, parallel-group, placebo- and active-controlled noninferiority trial

Controlling relapses of scalp psoriasis is a clinical issue. Zinc pyrithione heals the scalp by normalizing epithelial keratinization or sebum production, or both. Salicylic acid removes scaly hyperkeratotic skin. Supramolecular active zinc antidandruff hair conditioner can relieve the induration of scalp psoriasis lesions. Background Controlling the relapses of scalp psoriasis is a clinical issue. Objectives To evaluate the efficacy and safety of a supramolecular active zinc antidandruff hair conditioner in managing scalp psoriasis (SP). Methods This multicentre randomized, observed-blind, parallel-group, placebo- and active-controlled noninferiority trial enrolled 211 patients with SP between October 2018 and June 2019. The participants were randomized 1 : 1 : 1 to the experimental (supramolecular active zinc antidandruff hair conditioner), placebo (supramolecular hydrogel) or positive control (calcipotriol ointment) group. The primary efficacy endpoint was the disease control rate at the end of the fourth week of treatment, measured using the Investigator's Global Assessment score. Results This study included 70, 70 and 71 participants in the experiment, control and placebo groups, respectively. The disease control rates of SP at the end of week 4 of treatment in the full-analysis set (FAS) were 39%, 25% and 37% in the experimental, placebo and control groups. The margin of superiority between the experimental and placebo groups was > 0 [96% confidence interval (CI) 13.22% (0.43% to & INFIN;)] in the FAS. The experimental group was superior to the placebo group. The noninferiority margin between the experiment and control groups was > -15% [96% CI -1.43% (-14.91% to & INFIN;)] in the FAS. The experimental group was not inferior to the control group. Conclusions Supramolecular active zinc antidandruff hair conditioner was helpful for the treatment of SP, and it has good clinical efficacy in maintaining therapeutic effect and assisting in preventing the recurrence of psoriasis.