A partitioned survival analysis model was developed to predict costs and quality-adjusted life years (QALYs) for GnP and G. The time horizon of the model was set at 20 years. An annual discount rate of 2% for both costs and QALYs was applied. Data on overall survival and progression-free survival were derived from the Metastatic Pancreatic Adenocarcinoma Clinical Trial. Cost parameters were estimated from a Japanese medical claims database. The incremental cost-effectiveness ratio (ICER) of GnP compared with G was estimated. One-way sensitivity analysis was performed to assess the uncertainty in the parameter settings. In addition, scenario and probability sensitivity analyses were performed.
The incremental cost and QALY of GnP compared with G were US$25 089 and 0.13 QALY, respectively. The ICER of GnP was estimated to be US$192 992 per QALY gained. Although the ICER was influenced by utility parameters and the survival curves, the ICERs remained higher than the willingness to pay (WTP) threshold of US$68 000 (JPY 7.5 million). The probability that GnP becomes cost-effective compared with G was estimated to be 29.2%.
Applying the WTP threshold of US$68 000 per QALY, GnP was not cost-effective for patients with unresectable metastatic pancreatic cancer in Japan from the perspective of healthcare payer. Further research is needed to obtain utility data from Japanese patients with pancreatic cancer.
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