A Two-Stage Study of the Efficacy, Safety, Pharmacokinetics, Pharmacodynamics and Immunogenicity of Various Doses of Levilimab When Administered Intravenously and Subcutaneously to Healthy Subjects and Subjects With Active Rheumatoid Arthritis

This is a two-stage study of efficacy, safety, pharmacokinetics, pharmacodynamics, and immunogenicity of various doses of levilimab when administered intravenously and subcutaneously to healthy subjects and subjects with active rheumatoid arthritis resistant to methotrexate monotherapy. Aim of the Stage 1 is to study the tolerability, safety, immunogenicity, and main pharmacokinetic and pharmacodynamic parameters of levilimab after its single subcutaneous or intravenous administration at ascending doses to healthy subjects. Aim of the Stage 2 is to confirm the efficacy and safety of levilimab 648 mg IV Q4W in combination with methotrexate and levilimab 324 mg SC Q2W in combination with methotrexate in subjects with active rheumatoid arthritis, resistant to methotrexate monotherapy.