Cost Effectiveness of Adding Pembrolizumab to Platinum and Fluoropyrimidine-Based Chemotherapy as First-Line Treatment for Advanced Esophageal Cancer: A US Healthcare Payer's Perspective.

Abstract

Pembrolizumab plus cisplatin and fluorouracil demonstrated superior efficacy and comparable safety compared with fluorouracil and cisplatin (FP) as first-line treatment for locally advanced unresectable or metastatic carcinoma of the esophagus and gastroesophageal junction adenocarcinoma in a phase III trial (KEYNOTE-590). This study evaluated the cost effectiveness of pembrolizumab plus FP versus FP and versus a blended chemotherapy comparator including FP, carboplatin plus paclitaxel, FOLFOX, FOLFIRI, docetaxel plus FP, trastuzumab plus FP, and trastuzumab plus FOLFOX from a US healthcare payer's perspective. A partitioned survival model was developed with three health states (progression-free, progressive disease, and death). Overall survival, progression-free survival, time on treatment, and adverse events were informed by patient-level data from KEYNOTE-590. The blended chemotherapy comparator reflected the current US treatment landscape and was assumed to have similar efficacy and safety as FP. Health utilities were estimated using linear mixed-effects models based on EQ-5D-5L data from the trial. Resource use and cost inputs (2020 US dollars) were based on US standard sources and literature. Costs, life-years, and quality-adjusted life-years (QALYs) discounted at 3.0% per year and incremental cost-effectiveness ratio were outcomes in the model. Sensitivity and scenario analyses were conducted to assess the robustness of base-case results. Compared with FP, pembrolizumab plus FP produced a mean gain of 0.86 life-year and 0.77 QALY with additional costs of $112,630 over 37.6 years, yielding an incremental cost-effectiveness ratio of $147,097 per QALY. Results were similar when the intervention was pembrolizumab plus alternative chemotherapies or when blended chemotherapy became the comparator. Results were most sensitive to different overall survival extrapolation approaches. Our analysis suggests that pembrolizumab plus chemotherapy extended life-years and QALYs and is cost effective compared with chemotherapy alone as a first-line treatment for advanced esophageal cancer in the USA given a willingness-to-pay threshold of $150,000 per QALY.