Evaluate the Safety, Tolerability of BAT6026

This is a Phase IB/IIA clinical study of BAT6026 in patients with AD. The subjects were adults with moderate to severe atopic dermatitis (AD) whose disease was not adequately controlled by prior topical medications or for which topical medications were not appropriate. The first phase was the phase IB study, which was double-blind controlled by placebo in the group and consisted of 3 dose groups. After completing the dose escalation study, the phase IIA study was entered. The Phase IIA study was a randomized, double-blind, controlled, multicentering clinical trial with different dose groups and placebo groups. The primary endpoint was to explore the efficacy and safety of BAT6026 in patients with eczema area and severity index (EASI) of at least 75% lower than the baseline at week 16 after 4 treatment cycles. To provide the optimal dose for the phase III regimen.