High costs of precision medicine raise concerns about exacerbating income-related disparities in healthcare utilization and health outcomes. One approach to expanding coverage in Asia has been to cover the precision therapy but require the pharmaceutical firm to cover the costs of the companion diagnostic test. Taiwan’s National Health Insurance (NHI) adopted this approach for lung cancer, colorectal cancer and leukemia, but not for the first target therapy covered by NHI, trastuzumab for the treatment of HER2-positive breast cancer. Analyzing a unique dataset linking medical claims, cancer registry data and proxies for income between 2004 and 2015, we find that lower-income patients are more likely to be diagnosed with later stages of breast cancer, and this pattern renders NHI coverage of anti-HER2 therapy pro-poor even before full coverage of the diagnostic tests.

Moreover, the expansion of NHI coverage—including the FISH diagnostic test and trastuzumab for early-stage breast cancer—strengthened the pro-poor distribution of genetic testing and target treatment, albeit only marginally. The extent of pharmaceutical company coverage of testing and its impact on patient access are topics of our ongoing research, contrasting breast cancer with colorectal cancer.

Keywords: disparities, personalized medicine, income-related inequality, breast cancer, genetic testing, Taiwan, Asia