Background As new medications enter the market for rheumatoid arthritis (RA), economic evaluations of medications provide critical information for assessing cost-effectiveness.
Objectives To estimate incremental cost per quality-adjusted life-year (QALY) of tofacitinib 5 mg BID, a new treatment for moderate to severe RA after inadequate response to methotrexate (MTX), compared with the available/recommended treatment strategies as of 2014 using the Canadian third-party payer perspective and lifetime time horizon.
Methods A cost utility model allowing for the comparison of different treatment strategies (including and excluding tofacitinib 5 mg BID) was developed. The model is an individual patient simulation through a Markov-like model and reflected the 2012 Canadian Rheumatology Association recommendations for the pharmacological management of RA with the inclusion of tofacitinib 5 mg BID. Tofacitinib 5 mg BID was assumed to be placed in the treatment algorithm similar to the anti-TNF treatments, for moderate to severe RA after failure of conventional DMARDs including MTX. Patients switched treatments due to loss or lack of efficacy, and/or an adverse event (AE). Efficacy was measured using the continuous variable of Health Assessment Questionnaire-Disability Index (HAQ-DI) scores (and changes) using results of a mixed treatment comparison during the first 6 months of treatment and data from long-term extension trials for later treatment periods. Where available for individual products, meta-analysis data were used to estimate AE incidence, followed by individual trial data and registry estimates. Patient characteristics were estimated from Canadian sources. Costs and utility were derived from published data which mapped HAQ-DI scores onto healthcare resource utilisations/costs and EuroQol-5D utility scores in Canadian RA patients. All costs were estimated in 2014 Canadian dollars. Probabilistic and one-way sensitivity analyses were completed on analytical horizon, event rates and efficacy thresholds.
Results After running the model for 100000 simulations of moderate to severe RA patients, the treatment arm including tofacitinib had lifetime costs of $298434 with 8.17 QALYs. Comparatively, the treatment arm excluding tofacitinib had a lifetime cost of $305158 with 7.88 QALYs. Therefore, a treatment strategy including tofacitinib is dominant with lower costs and greater effectiveness. One-way and probabilistic sensitivity analysis reflect the robustness of these results with a >80% likelihood that the incremental cost-effectiveness ratio is <$30000/QALY.
Conclusions Our cost-effectiveness analysis demonstrates that, over a lifetime time horizon, and taking a third-party payer perspective, the inclusion of tofacitinib 5 mg BID into the treatment strategy for moderate to severe RA is a dominant strategy in Canada (lower cost and increased QALYs). Sensitivity analysis reiterates the robustness of results and cost-effectiveness of tofacitinib.
Acknowledgements This study was funded by Pfizer Inc.
Disclosure of Interest J. Woolcott Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, G. Blackhouse Grant/research support from: Pfizer Inc, L. Claxton Consultant for: Pfizer Inc, G. Wallenstein Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, T. Tran Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, R. Goeree: None declared, M. Taylor Consultant for: Pfizer Inc, D. Moynagh Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, A. Singh Shareholder of: Pfizer Inc, Employee of: Pfizer Inc