Based on the observed safety profile of COVA322, the sponsor decided to stop the clinical study.

This study is a randomised, double-blind, placebo-controlled, sequential, ascending single-dose, parallel group study to evaluate safety, tolerability, biological activity, and systemic exposure of COVA322 (tumor necrosis factor alpha (TNF-α) / interleukin 17 A (IL-17A) antibody fusion protein) in patients with stable chronic moderate-to-severe plaque psoriasis. Patients will receive ascending single-doses of COVA322 or placebo as a constant-rate i.v. infusion, followed by 12 weeks of evaluation.

Inclusion Criteria:

• Male or female subjects of any ethnic origin; women must be of non-childbearing potential
• Aged between 18 to 65 yrs inclusive
• Body weight of ≥ 40 kg and body mass index between 19 - 32 kg/m2 inclusive
• Established diagnosis of moderate to severe plaque psoriasis for at least 6 months prior to screening. The patients must meet all of the following criteria:
• Psoriasis involving ≥ 10% of body surface area
• Requirement of phototherapy or systemic therapy
• Psoriasis Area and Severity Index (PASI) score of ≥ 10
• Physician"s Global Assessment (PGA) score of ≥ 3
• stable disease

Exclusion Criteria:

• History of clinically relevant allergies or idiosyncrasies to COVA322
• Any history of clinically significant drug hypersensitivity following any therapy with a therapeutical biologic, or asthma, urticaria, or other allergic diathesis
• Clinically significant flare of psoriasis during the 12 weeks before randomization
• Current evidence of non-plaque forms of psoriasis
• Currently evidence of drug-induced psoriasis
• Evidence of any serious systemic or local infection within 3 months before screening
• Evidence of subclinical/latent tuberculosis infection
• History or any signs of lymphoproliferative disease, or a known malignancy or a history of malignancy within the previous 5 years
• History or current evidence of autoimmune diseases other than psoriasis
• Women of child-bearing potential
• Recent previous exposure to systemic psoriasis treatments, including anti-TNF-α therapies, immunosuppressive agents such as cyclosporine, mycophenolate, or tacrolimus, and other medications affecting the immune function
• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) level ≥ 2.5 times the upper limit of normal (ULN) at screening
• Serum creatinine level ≥ 1.5 times the ULN at screening
• Positive results in any of the virology tests for HIV-Ab, hepatitis C-virus antibody (HCV-Ab) and hepatitis B-virus surface antigen (HBsAg) or hepatitis B core antibody (HBc-Ab)