PCN236 A LANDMARK RESPONSE ANALYSIS TO DETERMINE COST-EFFECTIVENESS OF THIRD-LINE NIVOLUMAB MONOTHERAPY FOR SMALL CELL LUNG CANCER

Abstract

To present a cost-effectiveness analysis of nivolumab monotherapy versus third-line (3L) treatment in small cell lung cancer (SCLC) based on modelling of long-term survival by treatment response. A landmark response analysis was developed from a US payer perspective using 3L+ nivolumab-treated patients in CheckMate 032. A 4-month landmark period was selected for the base-case based on a published validated model. Parametric survival models were developed by 4-month response status (complete, partial, progressed disease, and stable, according to RECIST v1.1). The generalised gamma curve was used to model overall survival (OS) to 4-months to maintain consistency with partitioned survival models that were also conducted. Exponential curves were used to model OS beyond the 4-month landmark based on overall best-fit. A systematic literature review identified no randomised controlled or single-arm trials that reported outcomes separately for 3L SCLC patients for any treatment. As topotecan was frequently prescribed in real-world clinical practice (SEER and Flatiron electronic health database) for 3L SCLC patients, it was chosen as the comparator. Clinical inputs for topotecan were derived from Flatiron data with inclusion/exclusion criteria matched to 3L+ nivolumab-treated patients (IV and oral topotecan were assumed equivalent). A partitioned survival model was developed to model topotecan outcomes in the absence of survival data by response status. This was acceptable given the maturity of OS data resulting in little uncertainty in model outcomes. Nivolumab was associated with increased incremental life-years (1.10) and quality adjusted life-years (QALYs; 0.79) compared with IV and oral topotecan. These benefits were observed at additional cost of US$88,256 versus IV topotecan and US$58,062 versus oral topotecan. Incremental cost per QALY gained with nivolumab was US$111,054 versus IV topotecan and US$73,110 versus oral topotecan. Using landmark response analysis, nivolumab monotherapy is a cost-effective option for 3L+ treatment of SCLC compared with IV and oral topotecan.