Pembrolizumab vs chemotherapy in the first-line setting of PD-L1≥50% metastatic non-small cell lung cancer: A real-world cost-effectiveness analysis.

21 Background: Despite the voiced concerns around the initial economic decision models for first-line pembrolizumab in PD-L1≥50% metastatic non-small cell lung cancer (mNSCLC), there has been a paucity of evidence on the anticipated cost-effectiveness of pembrolizumab in the real world. To resolve the uncertainties associated with the initial assessment, we evaluated the real-world cost-effectiveness of first line pembrolizumab versus platinum-based chemotherapy for mNSCLC patients with PD-L1≥50%. Methods: We retrospectively identified a population-based cohort of mNSCLC patients who received first-line pembrolizumab or platinum-based chemotherapy between April 1, 2013, and March 31, 2021, in Ontario, Canada. Employing a public payer’s perspective, all costs (in Canadian dollars) and effects were estimated over a 4-year horizon, adjusted for censoring and discounted at 1.5% yearly. The primary outcomes were incremental cost-effectiveness ratios (ICERs) for life-years gained (LYG) and quality-adjusted life year (QALY). To examine the sensitivity of the ICER to drug acquisition costs and discounting, we conducted a price reduction analysis and a scenario analysis of different discount rates. Results: Propensity-score matching resulted in a total of 1,142 pairs of matched mNSCLC patients. Pembrolizumab extended survival with an incremental effect of 0.37 LYG and 0.35 QALY, but at an incremental cost of $56,681; the resulting ICERs were $154,941/LYG and $163,039/QALY. Though the ICERs were not sensitive to discounting rate, 31% and 55% reductions to the price of pembrolizumab brought the ICER below $100,000/QALY and $50,000/QALY, respectively. Conclusions: In the real world, first-line pembrolizumab is not considered to be cost-effective for mNSCLC patients with PD-L1≥50%. Improvements in cost-effectiveness, however, may be achievable through price renegotiations for pembrolizumab.