Costs and Health Outcomes Associated with Tofacitinib Treatment for Active Psoriatic Arthritis in the United States

BACKGROUND: Psoriatic arthritis (PsA) is a chronic progressive inflammatory condition associated with significant direct and indirect costs. Tofacitinib is an oral Janus kinase inhibitor for the treatment of PsA. Economic evaluations, alongside clinical data, help inform papers and formulary decisions in the United States. OBJECTIVE: To evaluate outcomes and costs of including tofacitinib in treatment strategies for PsA from a third-party U.S. payer perspective, using a health economic model. METHODS: A decision tree model was developed to evaluate treatment sequences (up to 4 lines of advanced PsA therapy) with or without tofacitinib. Patients included in the model had active PsA and a previous inadequate response (IR) to conventional synthetic disease-modifying antirheumatic drug (csDMARD) or tumor necrosis factor inhibitor (TNFi) therapy. The analysis time horizon was 2 years; decision points for continuing/switching treatments occurred quarterly, based on clinical response (assessed using the primary rheumatoid measure of efficacy, American College of Rheumatology [ACR]20 response only) and adverse drug reactions (ADRs). Costs included those related to ADRs and drug acquisition, monitoring, and administration. Other endpoints of PsA, such as assessment of enthesitis and dactylitis, were not integrated into the model. RESULTS: Treatment strategies including tofacitinib were associated with cost savings versus strategies without tofacitinib across all modeled scenarios, with an estimated 2-year cost saving of up to $8,454,858, based on 1 million insurants. Similarly, costs per member per month and per ACR20 responder were lower for sequences including tofacitinib versus sequences without. These savings arose because of lower ADR and drug acquisition/administration costs for sequences including tofacitinib. Deterministic sensitivity analyses showed these results to be robust. CONCLUSIONS: This analysis suggests that including tofacitinib in the treatment of active PsA in csDMARD-IR or TNFi-IR patients is a cost-saving alternative to sequences without tofacitinib, potentially reducing costs for PsA advanced therapies by up to $8.4 million over 2 years for payers insuring 1 million individuals.