this study is to evaluate the long-term safety including immunogenicity and efficacy of LBEC0101 50 mg subcutaneous weekly injection when co-administered with MTX for additional 48 weeks (a total of 100 weeks including 52 weeks of the treatment period in Study LG-ECCL002) in the subjects who have completed the treatment period of phase III clinical study for LBEC0101 (Study No. LG-ECCL002).