PCN89 A Cost-Effectiveness Analysis of Atezolizumab in Combination with Carboplatin and Etoposide in Patients with Untreated Extensive-Stage Small Cell Lung Cancer

Abstract

To assess the cost-effectiveness of atezolizumab in combination with carboplatin and etoposide (CE) compared to CE in the treatment of patients with untreated extensive-stage small cell lung cancer (ES-SCLC), in the Portuguese setting. A partitioned survival model including progression-free survival, post-progression survival and death health states was used to estimate the cost-effectiveness of atezolizumab in combination with CE, using data from the IMpower133, a phase III, randomized, double-blind, placebo-controlled trial. Utility weights were estimated using the proximity to death approach separately for on/off treatment and applying the EQ-5D-5L Portuguese value set to the patient reported outcomes from the IMpower133 trial. Portuguese-specific disease management resource use was based on a panel of clinical experts and on Portuguese diagnosis-related group microdata. The main sources for unit costs were national legislation and official drug cost databases. The analysis was conducted from NHS’s perspective, assuming a lifetime horizon and a 5% discount rate for both costs and effects. Deterministic and probabilistic sensitivity analyses were conducted to assess the robustness of results. Atezolizumab increases average life expectancy by 0.24 undiscounted life years (LY) or 0.22 undiscounted quality adjusted life years (QALY), enabling a discounted gain of 0.22 LY or 0.20 QALY. Economic analysis shows that the higher cost of the atezolizumab option is mainly due to higher treatment costs. The estimated incremental cost-effectiveness ratios are 124,218€/LY and 138.494€/QALY. Deterministic sensitivity analyses show that results are robust to most scenarios but sensitive to the parametric extrapolation options of the treatment duration and overall survival. Treatment with atezolizumab in combination with CE showed an incremental effectiveness both in terms of LY and QALY compared to CE alone. The cost-effectiveness model of atezolizumab in combination with CE in patients with untreated ES-SCLC was considered valid to support a reimbursement decision in the Portuguese setting.