A Study of AK111 in Subjects With Moderate-to-severe Plaque Psoriasis

Inclusion Criteria: 1. Moderate to severe plaque-type psoriasis diagnosed for at least 6 months; 2. Subjects with moderate-to-severe plaque psoriasis at baseline, who were defined as follows: Body Surface Area (BSA) ≥ 10%, PASI ≥ 12 and SPGA score ≥ 3; 3. Subjects with a history of systemic therapy or phototherapy for psoriasis at least once before, or suitable to receive systemic therapy or phototherapy for psoriasis assessed by investigator; 4. Women of childbearing age is not pregnant or lactating, and the subjects and their partners voluntarily take contraceptive measures considered effective by the investigator during the treatment period and at least 6 months after the last receipt of the study drug. Exclusion Criteria: 1. Forms of psoriasis other than chronic plaque-type psoriasis; 2. History or evidence of active/latent tuberculosis; 3. Positive results of confirmatory serology test for hepatitis B, hepatitis C,HIV or syphilis at screening; 4. History of serious infection within 2 months before screening; 5. History of malignancy of any organ system; 6. Inadequate washout period for prior psoriatic therapy; 7. Previous use of secukinumab, ixekizumab or any other drug that targets IL-17 or IL-17 receptor; 8. Any medical conditions, in the opinion of the investigator, would place the subject at risk, interfere with study participation or study results interpretation.