PCN81 Economic Evaluation of First-LINE Atezolizumab for Extensive-STAGE SMALL-Cell LUNG Cancer: The Difference between the Standard Parametric MODEL and the Mixture Cure MODEL

Abstract

This study evaluated the cost-effectiveness of atezolizumab + chemotherapy versus chemotherapy as first-line treatment for extensive-stage small-cell lung cancer (SCLC) in the US. The 3 health states partitioned survival (PS) model was used over the lifetime. Effectiveness and safety data were derived from the IMpower133 trial. The parametric survival model and mixture cure model were used for the atezolizumab + chemotherapy group, and the parametric survival model was used for the chemotherapy group. Costs were derived from the pricing files of Medicare and Medicaid Services, and utility values were derived from previous studies. Sensitivity analysis were performed to observe model stability. In model 1, compared with chemotherapy alone, atezolizumab + chemotherapy yielded an additional 0.11 quality-adjusted life-years (QALYs), with an incremental cost of US$84,257. The incremental cost-utility ratio (ICUR) was US$785,848/QALY. In model 2, atezolizumab + chemotherapy yielded an additional 0.10 QALYs, with an incremental cost of US$84,257; the ICUR was US$827,610/QALY. In the one-way sensitivity analysis, progression-free (PF) and postprogression (PP) utilities were the main drivers. In the scenario analysis (PF utility=0.673, PP utility =0.473), the results obtained with model 1 and model 2 showed that the ICUR was US$910,557/QALY and US$965,607/QALY, respectively. In the PSA on model 1 and model 2, the probabilities that atezolizumab + chemotherapy would not be cost-effective were 100% if the willingness-to-pay threshold was US$100,000/QALY. The findings of the present analysis suggest that atezolizumab + chemotherapy is not cost-effective in patients receiving first-line treatment for extensive-stage SCLC in the US.