Presentation (CTI)

OBJECTIVES: This study evaluated the cost-effectiveness of pembrolizumab either as monotherapy or in combination with platinum + 5- Fluorouracil (5-FU) versus cetuximab + platinum + 5-FU for the first line treatment of R/M HNSCC from a public healthcare system perspective in Brazil.
METHODS: A three-state partitioned survival model was developed consisting of two health states of progression-free and progressed disease, and a single state for death (all-causes), using efficacy and safety data from KEYNOTE-048 trial based on final analysis. Utility inputs were derived from the EQ-5D-3L data collected in KEYNOTE-048 using Brazilian algorithm. Costs and health outcomes were discounted based on an annual discount rate of 5.0%, following Ministry of Health guidelines. The health economic evaluation includes direct medical costs from the perspective of the Brazilian public health system, such as: drug acquisition, health state specific disease management costs, terminal care and adverse effects.
RESULTS: Over a lifetime horizon, pembrolizumab monotherapy demonstrated an incremental gain of 0.772 QALYs compared to cetuximab plus chemotherapy in the combined positive score (CPS) ≥ 1 population, with an additional cost of R$ 65,303. The incremental cost-effectiveness ratio (ICER) per QALY was R$ 84,557. Considering the all- comers population, there was an incremental gain of 0.911 QALYs at an additional cost of R$ 78,176 resulting in an ICER per QALY of R$ 85,828 for pembrolizumab combination therapy compared to cetuximab + platinum + 5-FU. These results were lower than the willingness-to-pay threshold of R$ 120.000 three times the gross domestic product (GDP) per capita of Brazil. Results were robust and consistent in sensitivity analyses.
CONCLUSIONS: Pembrolizumab either as monotherapy or in combination with chemotherapy provided grater QALY gains for patients with R/M HNSCC at small additional costs, making it a cost-effective treatment versus cetuximab + platinum + 5-FU in Brazil.