Cost-effectiveness of pembrolizumab in combination with chemotherapy in the 1st line treatment of non-squamous NSCLC in the US

Aims: To describe cost-effectiveness of pembrolizumab plus platinum and pemetrexed chemotherapy in metastatic, non-squamous, NSCLC patients in the US. Materials and methods: A model is developed utilizing partitioned survival analysis to estimate the cost-effectiveness of KEYNOTE-189 trial comparators pembrolizumab + chemotherapy (carboplatin/cisplatin + pemetrexed) vs chemotherapy alone. Clinical efficacy, treatment utilization, health utility, and safety data are derived from the trial and projected over 20 years. For extrapolating survival beyond the trial, a novel SEER population-data approach is applied (primary analysis), with separate estimation via traditional parametric extrapolation methods. Costs for drugs and non-drug disease management are also incorporated. Based on an indirect treatment comparison, cost-effectiveness of pembrolizumab + chemotherapy vs pembrolizumab monotherapy is evaluated for patients with programmed death-ligand 1 (PD-L1) >= 50%. Results: In the full non-squamous population, pembrolizumab + chemotherapy is projected to increase life expectancy by 2.04 years vs chemotherapy (3.96 vs 1.92), for an approximate doubling of life years. Resultant incremental cost-effectiveness ratios (ICERs) are $104,823/QALY and $87,242/life year. In patients with PD-L1 >= 50% and 1-49%, life expectancy is more than doubled (4.53 vs 1.88 years) and (4.87 vs 2.01 years), with a 32% (2.60 vs 1.97 years) increase in PD-L1 < 1% patients. Corresponding incremental costs/quality-adjusted life year (QALY) are $103,402, $66,837, and $183,529 for PD-L1 >= 50%, 1-49%, and <1% groups, respectively. Versus pembrolizumab monotherapy in PD-L1 >= 50% patients, representing current standard of care, pembrolizumab + chemotherapy increases life expectancy by 65% (4.53 vs 2.74 years) at an ICER of $147,365/QALY. Limitations and conclusions: The addition of pembrolizumab to chemotherapy is projected to extend life expectancy to a point not previously seen in previously untreated metastatic non-squamous NSCLC. Although ICERs vary by sub-group and comparator, results suggest pembrolizumab + chemotherapy yields ICERs near, or in most cases, well below a 3-times US per capita GDP threshold of $180,000/QALY, and may be a cost-effective first-line treatment for metastatic non-squamous NSCLC patients.