PCN97 Cost-Effectiveness of Atezolizumab Monotherapy Versus Pembrolizumab Monotherapy for First-Line Treatment of Metastatic Non-Small Cell Lung Cancer

Abstract

Atezolizumab is a programmed death ligand-1 (PD-L1) inhibitor indicated as first-line (1L) monotherapy for metastatic non-small cell lung cancer (mNSCLC) patients whose tumors have high PD-L1 expression (≥50%) without epidermal growth factor receptor or anaplastic lymphoma kinase mutations. This analysis aimed to evaluate the cost-effectiveness of 1L atezolizumab versus pembrolizumab monotherapy for mNSCLC patients with high PD-L1 expression from a US payer perspective. A Microsoft Excel-based Markov model with progression-free, progressive disease (PD), and death states was developed to compare clinical and cost outcomes of atezolizumab versus pembrolizumab monotherapy. Efficacy, safety, and utility data were derived from systematic reviews and network meta-analysis of published cancer immunotherapy agents. Product prescribing information and clinical trials informed dosing and administration. Wholesale acquisition cost (WAC, accessed in March 2020) for drugs were used while other cost inputs were from publicly available fee schedules and peer-reviewed literature. The main outcome was the incremental cost-effectiveness ratio (ICER) expressed as cost per quality-adjusted life-year (QALY) gained. Probabilistic sensitivity analysis (PSA) and one-way sensitivity analysis (OWSA) with 20% variation were performed to address uncertainties around input parameters. In the base case, 1L atezolizumab monotherapy was projected to increase patient’s life expectancy by 0.57 life-years (4.35 vs. 3.78) and 0.41 QALYs (3.17 vs. 2.76) over pembrolizumab monotherapy at an incremental cost of $22,581, resulting in an ICER of $54,549/QALY gained. The PSA demonstrated that atezolizumab had a 43% and 51% probability of being cost-effective at willingness-to-pay thresholds of $100,000 and $150,000, respectively. In the OWSA, results were most sensitive to changes in discount rates for costs and effects. Evidence suggests 1L atezolizumab monotherapy for mNSCLC patients with high PD-L1 expression was cost-effective when compared to pembrolizumab monotherapy. The projected mean ICER ($54,549/QALY) for atezolizumab monotherapy falls below the commonly used US cost-effectiveness thresholds (<US$100,000-$150,000/QALY).