The primary purpose of this study is to assess the percentage of participants achieving an American College of Rheumatology (ACR) 20 percent (%) Improvement (ACR20) response at Week 12 of the administration of the investigational product.

Inclusion Criteria:

1. Participants who voluntarily provided written consent to participate in this study

2. Male or female, aged greater than or equal to (>=) 19 years at the time of written informed consent

3. Participants diagnosed with rheumatoid arthritis according to the 2010 ACR/ European League Against Rheumatism (EULAR) classification criteria and who have an ACR functional class of I to III

4. Participants who meet the following criteria are eligible for the specified treatment protocol; those who have been treated with two or more type types (including MTX) of Disease-Modifying Antirheumatic Drugs (DMARDs) for at least 6 months (at least 3 months each) but have experienced insufficient therapeutic effects or have had to discontinue treatment due to adverse events of these medications (However, in cases where MTX is contraindicated due to conditions such as liver disease or renal failure, the participant must have been treated with at least two types of DMARDs, excluding MTX).

   • Furthermore, in participants over 65 years of age, those at high risk of cardiovascular diseases, and those with a potential risk of malignancy, this protocol applies if they have not adequately responded to or tolerated conventional therapies, including Tumor Necrosis Factor (TNF) inhibitors or other biologic agents. Eligibility is confirmed if one of the following criteria is met:

     1. DAS28 score exceeding 5.1.
     2. DAS28 score between 3.2 and 5.1, with diagnostic imaging showing progression of joint damage.

Exclusion Criteria:

1. Participants with hypersensitivity reactions to the active ingredient or other components of the investigational product
2. Participants with serious infections (for example [e.g.], sepsis) or active infections including localized infections
3. Participants with active tuberculosis (TB)
4. Participants with severe hepatic impairment (e.g., Child-Pugh C)
5. Participants with end-stage renal disease (\

Eisai's data sharing commitment and further information on how to request data can be found on our website http://eisaiclinicaltrials.com/.