Comparative Cost-Effectiveness of Gemcitabine and Cisplatin in Combination with S-1, Durvalumab, or Pembrolizumab as First-Line Triple Treatment for Advanced Biliary Tract Cancer

Purpose The clinical effectiveness of triple chemotherapy consisting of gemcitabine, cisplatin plus either S-1 (GCS), durvalumab (DGC), or pembrolizumab (PGC) as first-line treatment for advanced biliary tract cancer (BTC) has been reported. However, their comparative cost-effectiveness is unclear. We conducted a model-based cost-effectiveness analysis from the perspective of Japanese healthcare payer. Methods A 10-year partitioned survival model was constructed by comparing the time-dependent hazards of the KHBO1401-MITSUBA, TOPAZ-1, and KEYNOTE-966 trials. The cost and utility came from previously published reports. Quality-adjusted life years (QALY) were used to measure the effects on health. Costs for direct medical care were taken into account. There was a one-way analysis and a probability sensitivity analysis. A willingness-to-pay threshold of 7.5 million yen (57,034 USD) per QALY was defined. Results The incremental costs per QALY for GCS, DGC, and PGC in the base case study were 3,779,374 JPY (28,740 USD), 86,058,056 JPY (65,4434 USD), and 28,982,059 JPY (220,396 USD), respectively. No parameter had an influence beyond the threshold in a one-way sensitivity analysis. A probabilistic sensitivity analysis revealed that the probability of GCS, DGC, and PGC being cost-effective at the threshold was 85.6%, 0%, and 0%, respectively. Conclusion Given the current circumstances, it is probable that triple therapy utilizing GCS will emerge as a plausible and efficient primary chemotherapy strategy for patients with advanced BTC in the Japanese healthcare system, as opposed to DGC and PGC.