Consideration of the Cost of Adverse Events for Oncology Treatment: A Review of Cost-Effectiveness Evaluations in Japan

OBJECTIVES: Cost-effectiveness evaluation (CEE) guidelines for Japan recommend, in principle, that the estimation of healthcare costs (HCs) include not only the costs of the selected technology and its comparator(s) but also HCs associated with adverse events (AEs) for cost-effectiveness analyses (CEA). In the case of oncology treatment, a certain frequency of AEs is inevitable, and it is common for treatments to be continued while appropriately addressing AEs. However, AEs may differ by treatment in terms of their severity and frequency. We consider HCs associated with AEs for CEEs for oncology treatments in Japan in terms of AE severity and frequency.

METHODS: We reviewed published academic group analyses for CEEs for oncology treatments that were evaluated in Japan between April 2019 and December 2023. Only base-case analyses were included. For HCs associated with AEs, we examine their severity and frequency based on their grades and rates, respectively.

RESULTS: 13 reports covering seven treatments / indications were identified. Of these, 12 included HCs associated with AEs. In terms of severity, only HCs associated with AEs of Grade 3 or higher were considered for most reports (n=9, 75.0%) and three reports (25.0%) did not report AE grade. Among the 12 reports, six (50.0%) considered HCs associated with an AE frequency of 5% or more. Two reports (16.7%) used a bespoke definition for AE frequency (e.g., 2% or more difference between the selected treatment and the comparator). Others (n=4, 33.3%) did not report the frequency of AEs.

CONCLUSIONS: In most cases, only HCs for AEs of Grade 3 or higher are included in CEEs in Japan. In terms of frequency, half of evaluations included HCs for AEs occurring in 5% or more of patients. However, some CEEs did not report the details of AEs in terms of their severity and frequency.