Association of immune checkpoint inhibitor introduction and changes in survival disparities by health insurance coverage among individuals newly diagnosed with advanced cancers in the US.

1580 Background: First approved by the US Food and Drug Administration (FDA) in 2011, immune checkpoint inhibitors (ICIs) have transformed treatment options for many cancers. Unfortunately, due to their high cost, individuals without health insurance coverage may not be able to afford them. Therefore, the introduction of ICIs may lead to greater disparities in cancer survival between patients with and without health insurance. This study examined the association of health insurance with changes in survival disparities associated with the introduction of ICIs. Methods: We identified individuals newly diagnosed at age 18-64 years at stage IV with any one of the following cancers with FDA approval for ICI treatment, including melanoma (first approved 03/25/2011, n=9992); HR+ HER- female breast cancer (02/03/2015, n=13632); non-small cell lung cancer (NSCLC; 03/04/2015, n=113866); and renal cell carcinoma (RCC; 11/23/2015, n=15403) from the National Cancer Database. Individuals with private health insurance or who were uninsured at the time of the cancer diagnosis were included. For each cancer, we applied a difference-in-differences (DD) approach to examine the changes in two-year overall survival before and after the ICI FDA approval date among individuals without health insurance compared to those with private health insurance, using flexible parametric survival models and controlling for key sociodemographic factors. Results: As shown (Table), among patients diagnosed with melanoma, 2-year survival rate increased from 16.33% pre-ICI approval to 27.04% after ICI approval among patients who were uninsured and increased from 28.22% to 45.45% among patients with private health insurance, with the disparity by health insurance status widened by 4.58 (95% confidence interval CI = 0.02 to 9.14) percentage points (ppt) after adjusting for sociodemographic factors. For patients diagnosed with stage IV NSCLC, the disparity by health insurance widened by 1.58 (95% CI = 0.52 to 2.64) ppt. Conclusions: The introduction of ICIs increased disparities in survival by health insurance status. Policies to improve health insurance coverage options or make new treatments more affordable to uninsured patients are needed. Table: see text