METHODS: Using a decision tree model, clinical and economic outcomes associated with olanzapine-containing regimen and standard antiemetic regimen (doublet antiemetic regimen: dexamethasone+first generation 5HT3RA) in most SEA countries except in Singapore (triplet antiemetic regimen: dexamethasone+first generation 5HT3RA + aprepitant) for CINV prevention following HEC were evaluated. This analysis was performed in Thailand, Malaysia, Indonesia, and Singapore, using societal perspective method with 5-day time horizon. Input parameters were derived from literature, network meta-analysis, government documents, and hospital databases. Outcomes were incremental cost-effectiveness ratio (ICER) in USD/quality-adjusted life year (QALY) gained. A series of sensitivity analyses including probabilistic sensitivity analysis were also performed.

RESULTS: Compared to doublet antiemetic regimen, addition of olanzapine resulted in incremental QALY of 0.0022-0.0026 with cost saving of USD 2.98, USD 27.71, and USD 52.20 in Thailand, Malaysia, and Indonesia, respectively. Compared to triplet antiemetic regimen, switching aprepitant to olanzapine yields additional 0.0005 QALY with cost saving of USD 60.91 in Singapore. The probability of being cost-effective at a cost-effectiveness threshold of 1 GDP/capita varies from 14.7 to 85.2% across countries.