Efficacy and Safety of Fecal Microbiota Transplantation in Patients With Rheumatoid Arthritis Refractory to Methotrexate

Inclusion Criteria: * Age 18-65 years with informed consent * Fulfill the 2010 ACR/EULAR classification criteria for rheumatoid arthritis * Positive RF or anti-CCP antibody on screening * Have active RA shown by swollen joint count(SJC)≥4 and tender joint count(TJC)≥4 and ESR \>28 mm/hr or C-reactive protein \> 1.5 ULN * Have received methotrexate for 3 months or longer and at a stable dose of 7.5 to 25 mg/week (extremes included) for at least four weeks prior to screening and willing to continue on this regimen for the duration of the study. * Class I, II or III of the ACR 1991 Revised Criteria for Global Functional Status in RA * If taking oral steroids, these should be at a dose ≤10 mg/day of prednisone or prednisone equivalent and stable for at least four weeks prior to screening; * If taking non-steroidal anti-inflammatory drugs (NSAIDs), these must be at a stable dose for at least two weeks prior to screening; * Female subjects must have a negative pregnancy test unless they are surgically sterile or have been post-menopausal for at least one year (12 consecutive months without menses); * Women of childbearing potential must use a medically acceptable means of birth control and agree to continue its use during the study and for at least four weeks after the last dose of study drug. Sexually active men must agree to use a medically acceptable form of contraception during the study and continue its use for at least 3 months after the last dose of study drug; and * Willing to suspend the use of other adjuvant treatment for the duration of the study including acupuncture, massage, etc. Exclusion Criteria: * Pregnant, lactating or further fertility requirements * History of any inflammatory rheumatological disorders other than RA; * Previously received any biologic agents. * Treatment with disease-modifying antirheumatic drugs (DMARDs), other than background methotrexate; * Receipt of an intra-articular or parenteral corticosteroid injection within four weeks prior to screening; * Active or chronic infection, including HIV, HCV, HBV, tuberculosis. * Malignancy or history of malignancy. * Severe, progressive, or uncontrolled cardiac, pulmonary, renal, hepatic, gastrointestinal, hematologic, metabolic, endocrine or neurologic disease * unable to undergo colonoscopy.