Selective JAK Inhibition in RA vs PV
Tofacitinib induced remission of rheumatoid arthritis but spared JAK2-driven polycythemia vera in a single case report.
By
Julia Cipriano
February 13, 2026
Clinical Scorecard: Selective JAK Inhibition in RA vs PV
At a Glance
Category Detail
Condition Rheumatoid Arthritis with Polycythemia Vera Key Mechanisms Selective inhibition of JAK1 and JAK3, sparing JAK2 activity. Target Population Patients with seropositive rheumatoid arthritis and JAK2 V617F-positive polycythemia vera. Care Setting Rheumatology and hematology clinics.
Key Highlights
Tofacitinib demonstrated efficacy in RA but minimal effect on PV-related hematologic activity. Patient achieved clinical and ultrasonographic remission of RA within 3 months of tofacitinib initiation. Hematologic parameters remained stable during follow-up. Limited impact on erythrocytosis highlights need for JAK2-directed therapies. No adverse events or cytopenias reported after 12 months. Guideline-Based Recommendations
Diagnosis
Diagnosis of RA based on chronic symmetric polyarthritis and positive autoantibodies. Bone marrow biopsy to confirm PV. Management
Initiate treatment with tofacitinib for RA in patients with concomitant PV. Continue hydroxyurea for PV management. Monitoring & Follow-up
Regular assessment of inflammatory markers and joint symptoms. Monitor hematologic parameters to avoid complications. Risks
Potential for recurrence of erythrocytosis with hydroxyurea tapering. Patient & Prescribing Data
61-year-old woman with seropositive RA and JAK2 V617F-positive PV.
Tofacitinib effectively induced RA remission while maintaining hematologic safety.
Clinical Best Practices
Consider JAK2-directed therapies for patients with overlapping autoimmune and myeloproliferative diseases. Monitor for gastrointestinal intolerance and skin reactions when prescribing DMARDs. Related Resources & Content
