Abstract

Objectives

The Japanese government has introduced reimbursement incentive policies designed to promote biosimilar adoption for oncology biologics, including the provision of a financial incentive of ¥1500 (approximately $10) per prescription to physicians who prescribe biosimilars. This study aimed to evaluate the impact of Japan’s reimbursement policies on the uptake of oncology biosimilars, specifically trastuzumab and bevacizumab, in the outpatient setting.

Methods

We conducted an interrupted time series analysis using the health insurance claims database to assess the impact of the policy on biosimilar uptake, comparing trends before and after the policy intervention.

Results

The analysis incorporated 22 440 trastuzumab and 14 022 bevacizumab claims. For trastuzumab, interrupted time series analysis showed a significant slope change after policy implementation, with a slope change of 0.33% per month (95% CI 0.07-0.58). In contrast, bevacizumab did not exhibit significant changes in slope or level postintervention; however, its biosimilar uptake steadily increased over the entire study period.

Conclusions

This study suggests that reimbursement incentives have significantly enhanced the uptake of trastuzumab biosimilars in Japan, whereas bevacizumab has not exhibited a similar response. Given these findings, it is crucial for policy makers to design reimbursement strategies that are specifically tailored to the characteristics of each biosimilar to optimize their effectiveness.