A Clinical Study of TQH3821 Tablets in the Treatment of Treated 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.