Patients who have been withdrawn after receiving escape therapy or completed treatment during 24weeks in CWP-TCZ301 study

Patients who able to enroll in this study within 12 weeks after last infusion of CWP-TCZ301

Willing to give written informed consent

History of severe allergic or anaphylactic reactions to Investigational product in CWP-TCZ301 study

ALT or AST \> ULNⅹ2.5

Platelet count \< 100ⅹ103/ μL

WBC \< 3,000/mm3

Absolute neutrophil count \< 1,000/mm3

Absolute lymphocyte count \< 500/mm3

Total bilirubin \> ULNⅹ2

To Evaluate 1 Year Extension Study of the Efficacy and Safety of Tocilizumab in Patients With Moderate to Severe Rheumatoid Arthritis