Per sponsor request.

To evaluate the efficacy and safety of TQH3821 in treated patients with moderate-to-severe active rheumatoid arthritis.

Inclusion Criteria:

• Subjects voluntarily participate in this study and sign informed consent;
• Male and female, ≥18 years old and ≤70 years old (subject to the date of signing the informed consent);
• The diagnosis meets the rheumatoid arthritis (RA) classification criteria jointly established by the American College of Rheumatology (ACR) and the European Alliance against Rheumatism (EULAR) in 2010, for at least 3 months ;
• Moderate to severe active RA was defined by the following criteria: joint swelling ≥6 (based on 66 joints), joint tenderness ≥6 (based on 68 joints), Disease activity score 28-C-reactive protein (DAS28-CRP) ≥3.2, and CRP>10mg/L or erythrocyte sedimentation rate (ESR) >28mm/h;
• At least 12 weeks of treatment with methotrexate (dose 7.5 to 25 mg/ week) and stable dose (7.5 to 25 mg/ week) ≥4 weeks prior to initial administration of the study drug (oral stable dose methotrexate will be continued as background therapy during the trial);
• The subjects can attend the study visit on time and complete the visit;

Exclusion Criteria:

• 8 weeks before baseline examination, subjects underwent joint surgery or received intraarticular glucocorticoid therapy at the joint sites evaluated in this study;
• Patients with rheumatoid arthritis with joint functional activity grade Ⅳ or confined to a wheelchair or bed;
• Current or previous inflammatory joint diseases other than RA and other autoimmune venereal diseases;
• Patients with lung diseases deemed unsuitable for the study by the investigator;
• Cardiovascular and cerebrovascular abnormalities;
• Abnormal thyroid function;
• Subjects with a history or suspected demyelinating disease of the central nervous system;
• Have any type of active malignant tumor or have a history of malignant tumor;
• Presence of active Mycobacterium tuberculosis (TB) infection or latent TB infection without appropriate treatment;
• Have any acute or chronic active infectious disease;
• There are serious poorly controlled diseases;
• People with active hepatitis, or hepatitis B surface antigen (HBsAg) positive, hepatitis B core antibody (HBcAb) positive + hepatitis B virus (HBV) DNA positive, or hepatitis C virus (HCV) antibody-positive;
• History of human immunodeficiency virus (HIV) infection, or positive HIV serological results at screening, and positive antibodies to treponema pallidum during screening;
• Subjects who had suffered a severe trauma, fracture, or surgical procedure within 8 weeks prior to screening, or who were expected to require major surgical procedures during the study period;
• Female subjects who are pregnant or lactating;
• Those who received live attenuated vaccine within 28 days before the start of treatment, inactivated vaccine within 7 days, or planned vaccination during the study period;
• The subject has any medical condition that may affect oral drug absorption, gastrectomy or gastrointestinal disease of clinical significance.