Dose Ranging Study of ART621 in Subjects Diagnosed With Rheumatoid Arthritis Taking Methotrexate

Despite being effective in approximately 60% of subjects, there are limitations to existing anti-TNF therapies especially in relation to immunogenicity, safety and administration. In addition, due to their high molecular weight, currently marketed products are largely confined to the blood stream. ART621 is an anti-TNF molecule that contains 2 identical domain "antibodies" that have the binding activity of a full antibody but with a substantially smaller molecular size. The molecular weight of approximately half that of full size antibodies is predicted to, a) have improved tissue penetration and, b) to be less immunogenic than full size antibodies. This clinical trial is designed to assess the safety, efficacy, tolerability, immunogenicity and pharmacokinetics of ART621 when administered with an intravenous loading dose followed by subcutaneous administration every week.