PMS42 - Cost-Effectiveness of Sequential Treatment Strategies with Tnf-Inhibitors in Patients with Ankylosing Spondylitis: A Patient-Level Simulation Model

Abstract

To assess cost-effectiveness of sequential treatment strategies after inadequate response to treatment with one, two, or three tumor necrosis factor (TNF) inhibitors in patients with ankylosing spondylitis (AS). Patient-level Markov models were constructed from the US healthcare payer’s perspective. Initially, treatment responses were generated at the end of 12-week treatment based on recent meta-analyses of TNF-inhibitors for treatment of AS. Patients who responded to treatment would enter a “Responders” Markov model with 3 health states: death, withdrawal, or continuing treatment with TNF-inhibitor. Patients entered a “Non-Responders” Markov model with 2 health states: death or continuing conventional care (CC), if they inadequately responded to treatment. In sequential treatment strategy with two TNF-inhibitors, patients who inadequately responded to treatment with the first TNF-inhibitor received a second TNF-inhibitor. For sequential treatment strategy with three TNF-inhibitors, patients received a third TNF-inhibitor if they failed both first and second TNF-inhibitors. Health utility was estimated based on the BASFI and BASDAI scores. The models accounted for real-world adherence of TNF-inhibitor treatment. One-way and probabilistic sensitivity analyses were performed to test the robustness and uncertainty of the model results. Over 40-year time horizon and 100,000 simulated patients for each treatment strategy, base-case results produced average total discounted per-patient costs of $43,598, $115,778, $149,923, and $167,905; and quality-adjusted life years (QALYs) per patient of 8.571, 10.140, 11.532, and 12.317 for CC, treatment strategies with one TNF-inhibitor, two TNF-inhibitors, and three TNF-inhibitors, respectively. The sequential treatment with three TNF-inhibitors was the most cost-effective treatment strategy with an incremental cost-effectiveness ratio of $23,948/QALY relative to treatment strategy with one TNF-inhibitor. The current study suggested that all 3 sequential treatment strategies with TNF-inhibitors are cost-effective compared to the conventional care with the sequential treatment with three TNF-inhibitors was the most cost-effective and optimal treatment strategy.