Musculoskeletal Ultrasound Assessment of Therapeutic Response of Tofacitinib in Rheumatoid Arthritis Patients

Inclusion Criteria:

1. Patient must meet 1987 ACR criteria
2. Age > 18 years of age
3. Baseline DAS28/ESR>=3.2
4. Stable concomitant DMARDs
5. Stable prednisone <10mg or equivalent
6. Power Doppler score of >=10
7. Female subjects of childbearing potential must test negative for pregnancy
8. Male and female subjects of childbearing potential must agree to use contraception throughout the study
9. Negative QuantiFERON Gold test at screening

Exclusion Criteria:

1. No active TB
2. Prednisone >10 mg
3. Pregnancy or breast feeding
4. Prior treatment with tofacitinib
5. Concomitant biologic therapy (TNF inhibitors, IL-6 inhibitors, etc.)
6. Active infection with HIV, hepatitis B or C, or herpes zoster

7. Subjects with any uncontrolled clinically significant laboratory abnormality or any of the following laboratory abnormalities:

   1. Evidence of hematopoietic disorder or hemoglobin <9 g/dL
   2. Absolute lymphocyte count <0.75 x 109/L (<750/mm3)
   3. Absolute neutrophil count <1.2 x 109/L (<1200/mm3)
   4. Platelet count <100 x 109/L (<100,000/mm3)
   5. Alanine aminotransferase (ALT), or aspartate aminotransferase (AST) >1.5 times the upper limit of normal (x ULN)
   6. Estimated GFR <40 ml/min
8. Subjects who have received live or live attenuated vaccines within 6 weeks prior to the first dose of study drug (or the zoster vaccine)
9. Subjects who require concomitant treatment with medications that are potent inhibitors of cytochrome P450 3A4 (CYP3A4), both moderate inhibitors of CYP3A4 and potent inhibitors of CYP2C19, and potent CYP inducers (See Appendix)