Abstract 1409P
Background
Pembrolizumab plus cisplatin and 5-fluorourcil (5-FU) has demonstrated superior efficacy and comparable safety compared with cisplatin plus 5-FU as a first-line (1L) treatment for locally advanced unresectable or metastatic carcinoma of the esophagus and gastroesophageal junction adenocarcinoma in a phase III trial (KEYNOTE-590). This study evaluates the cost-effectiveness of pembrolizumab plus chemotherapy vs. alternative treatment options from a US third-party healthcare payer’s perspective with a 20% cost-sharing assumption.
Methods
A partitioned survival model containing three health states (progression-free, progressive disease, and death) was developed. Overall survival, progression-free survival, time on treatment, and adverse events were informed by the patient level data from KEYNOTE-590. The blended chemotherapy comparator reflected the current treatment landscape in the US and was assumed to have the same efficacy and safety as cisplatin plus 5-FU. Health utilities were estimated using linear mixed-effects models based on EQ-5D-5L data collected from the trial. Resource use and cost data were based on US standard sources and literature. The model reported costs, life years (LY), quality-adjusted life years (QALY), and incremental cost-effectiveness ratio (ICER). Sensitivity and scenario analyses were conducted to assess the robustness of the results. All outcomes and costs were discounted by 3% annually.
Results
Over a 40-year time horizon, pembrolizumab plus cisplatin and 5-FU resulted in a mean gain of 0.86 LY and 0.77 QALY with additional costs of $91,020vs. cisplatin plus 5-FU, leading to an ICER of $118,875/QALY. The results were similar with pembrolizumab plus alternative chemotherapy as the intervention or with blended chemotherapy as the comparator. Model results were most sensitive to the choice of overall survival extrapolation approach.
Conclusions
Pembrolizumab plus chemotherapy extends life years and QALYs and, with a willingness-to-pay threshold of $150,000/QALY, can be considered cost-effective vs. chemotherapy as 1L treatment of advanced esophageal cancer in the US.
Clinical trial identification
NCT03189719.
Editorial acknowledgement
Legal entity responsible for the study
Merck & Co.
Funding
Merck & Co.
Disclosure
T. Qu: Other, Institutional, Funding: Merck & Co. Y. Zhong: Non-Financial Interests, Personal, Full or part-time Employment: Merck & Co. S. Zhang: Non-Financial Interests, Personal, Full or part-time Employment: Merck & Co. Y. Meng: Other, Institutional, Funding: Merck & Co. S. Joo: Non-Financial Interests, Personal, Full or part-time Employment: Merck & Co. S. Shah: Non-Financial Interests, Personal, Full or part-time Employment: Merck & Co.