Rheumatoid arthritis patients that have failed DMARD therapy will undergo a synovial biopsy under ultrasound guidance and sterile technique. Upon analysis of the sample, patients that are falling into the diffuse myeloid phenotype will be assigned to receive anti-TNF medication at the discretion of the treating physician.

Rheumatoid arthritis patients that have failed DMARD therapy will undergo a synovial biopsy under ultrasound guidance and sterile technique. Upon analysis of the sample, patients that are falling into the lymphoid- myeloid phenotype will be assigned to receive JAK inhibitor medication at the discretion of the treating physician.

Rheumatoid arthritis patients that have failed DMARD therapy will undergo a synovial biopsy under ultrasound guidance and sterile technique. Upon analysis of the sample, patients that are falling into the pauci-cellular phenotype will be randomized to either anti-TNF or JAK inhibitor medication 1:1.

Upon analysis of the sample, patients that are falling into specific phenotypes (diffuse myeloid or pauci-cellular phenotypes) will be assigned to receive anti-TNF as biologic DMARD medications.

Change in DAS28 score indicating remission compared to baseline in at least 50% of patients, where DS28<2.6 indicated remission.

* DAS score: disease activity score, where <2.6 indicates remission, 2.6-3.2 low disease activity. 3.2-5.1 moderate disease activity; >5.1 high disease activity; higher values suggest worse outcomes.

Significant decrease in HAQ score compared to baseline.

* HAQ (Health assessment questionnaire). Scores vary from 0-to 3. Higher scores are associated with worse outcomes.