Cost-Utility Analysis of Pembrolizumab Versus Chemotherapy as First-Line Treatment for Metastatic Non-Small Cell Lung Cancer with Different PD-L1 Expression Levels

To evaluate the cost-utility of pembrolizumab versus chemotherapy as the first-line setting for metastatic nonsmall cell lung cancer (NSCLC) from the US health care system perspective, a Markov model was developed to compare the lifetime cost and effectiveness of pembrolizumab versus chemotherapy for untreated metastatic NSCLC, based on the clinical data derived from phase III randomized controlled trial (KEYNOTE-042; ClinicalTrials.gov; NCT02220894). Weibull distribution was fitted to simulate the parametric survival functions. Drug costs were collected from official websites, and utility values were obtained from published literature. Total costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) were computed as primary output indicators. The impact of different PD-L1 expression levels on ICER was also evaluated. One-way and probabilistic sensitivity analyses were performed to assess the model uncertainty. Compared with chemotherapy, patients treated with pembrolizumab provided an additional 1.13, 1.01, and 0.59 QALYs in patients with PD-L1 expression levels of ≥50%, ≥20%, and ≥1%, with corresponding incremental cost of $53,784, $47,479, and $39,827, respectively. The resultant ICERs of pembrolizumab versus chemotherapy were $47,596, $47,184, and $68,061/QALY, in three expression levels of PD-L1, respectively, all of which did not exceed the WTP threshold of 180,000/QALY. Probability sensitivity analysis outcome supported that pembrolizumab exhibited evident advantage over chemotherapy to be cost-effective. One-way sensitivity analysis found that ICERs were most sensitive to utility value of pembrolizumab in progression survival state. All the adjustment of parameters did not qualitatively change the result. For treatment-naive, metastatic NSCLC patients with PD-L1+, pembrolizumab was estimated to be cost-effective compared with chemotherapy for all PD-L1 expression levels at a WTP threshold of $180,000/QALY in the context of the US health care system.