To evaluate the long-term safety including immunogenicity and efficacy of LBEC0101 50 mg subcutaneous weekly injection when co-administered with MTX

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).

Inclusion Criteria:

• Patients who completed the treatment period of Study LG-ECCL002
• Patients requiring continuous treatment for rheumatoid arthritis upon the investigator's discretion
• For childbearing female patients or surgically non-sterile male patients, those who agreed to avoid pregnancy using proper contraceptive methods during the study.
• Patients who made a voluntary decision to participate in this clinical study and gave a voluntary written consent to comply with all the instructions with full understanding after being informed of the study

Exclusion Criteria:

• Patients deemed difficult to participate in this extension study due to the adverse events which occurred in Study LG-ECCL002, upon the investigator's discretion at screening
• Patients with at least 10 swollen joints (out of the total 66 assessing joints) or at least 12 tender joints (out of the total 68 assessing joints) at screening
• Women in pregnancy or lactation, or patients planning to be pregnant during the study period
• Patients ineligible for this clinical study upon the investigator's discretion