Modeling Systemic Lupus Erythematosus Treatment Cost-Effectiveness Based on a Novel Lupus Low Disease Activity State Treat-to-Target Approach

OBJECTIVES: To demonstrate a new cost-effectiveness modeling approach in systemic lupus erythematosus (SLE), using treat-to-target health states defined by Lupus Low Disease Activity State (LLDAS). METHODS: A Markov Cohort State Transition Model evaluated the cost-effectiveness of anifrolumab plus standard of care (SOC) versus SOC in patients with moderate to severe SLE, by integrating the effects of disease activity and oral corticosteroid use on organ damage and mortality into 24 health states defined by LLDAS ("in LLDAS" or "Not in LLDAS") and Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index scores (SDI 0 to ≥5). Transition probabilities, costs, and utilities were derived from observational cohort studies and phase 3 TULIP trial data. Quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) were calculated (Australian dollars, 2023 prices), and supported by sensitivity analyses. RESULTS: Anifrolumab base-case results were $298 031 for discounted total costs and 9.099 for discounted total QALYs; SOC values were $280 426 and 8.952, respectively. There were incremental costs of $17 605 and QALYs of 0.147 with anifrolumab, leading to an ICER of $119 841/QALY. Probabilistic sensitivity analyses supported these findings. One-way sensitivity analyses identified LLDAS attainment rates at week 24 with anifrolumab vs SOC as the most influential parameter to the ICER, followed by mortality for patients "Not in LLDAS" vs "in LLDAS." Health-related quality of life and flares also influenced the ICER. CONCLUSIONS: Our model offers a simple and robust approach to assessing the cost-effectiveness of SLE treatments using validated and recommended treatment targets for patients with SLE.