Tocilizumab biosimilar (Taizhou Mabtech)

1. Compare the similarity of the efficacy of CMAB806 and Acteluo® in combination with methotrexate in the treatment of moderately and severely active rheumatoid arthritis in adults; 2. Compare the safety of CMAB806 and Acteluo® in combination with methotrexate in the treatment of moderately and severely active rheumatoid arthritis in adults; 3. Compare the immunogenicity of CMAB806 and Acteluo® in adults with moderately and severely active rheumatoid arthritis;

Primary objective: To observe the pharmacokinetic characteristics of CMAB806, and to compare the main pharmacokinetic parameters of the two preparations with tocilizumab injection (Acmero®) produced by Chugai Pharma Manufacturing Co., Ltd. as the reference preparation, and to evaluate the pharmacokinetic similarity of the two preparations. Secondary objective: To compare the safety and tolerability of CMAB806 and Actemro® in Chinese healthy male volunteers after a single intravenous infusion of 4 mg/kg, and the clinical immunogenicity of the two preparations in Chinese healthy male subjects after a single intravenous infusion of 4 mg/kg.