Immune Checkpoint Inhibitors and Survival Disparities by Health Insurance Coverage Among Patients With Metastatic Cancer.

Importance: The introduction of immune checkpoint inhibitors (ICIs) has been associated with substantial improvement in median survival among individuals with cancer; however, people without health insurance coverage may be unable to afford ICIs due to their high costs. Objective: To examine the association between the introduction of ICIs and changes in survival disparities by health insurance coverage among people with a new diagnosis of advanced-stage cancer. Design, Setting, and Participants: This cross-sectional study was conducted among individuals who received a new diagnosis at age 18 to 64 years of stage IV melanoma (n = 12 048), non-small cell lung cancer (NSCLC; n = 152 610), or renal cell carcinoma (RCC; n = 18 782) who were identified from the National Cancer Database before and after US Food and Drug Administration approval of ICIs (January 1, 2002, to December 31, 2019, for melanoma and January 1, 2010, to December 31, 2019, for other cancers). Statistical analysis was conducted from December 2023 to April 2025. Exposure: Health insurance coverage at the time of diagnosis (private, Medicaid, or uninsured). Main Outcomes and Measures: The primary study outcome was 2-year overall survival. For each type of cancer, a 6-group propensity score weighting difference-in-differences (DID) approach was applied to examine the changes in 2-year survival before and after the ICI approval date among individuals without insurance or with Medicaid compared with those with private insurance. Results: Among the 183 440 individuals included, the mean (SD) age was 55.5 (7.0) years, and 56.5% were male. Two-year overall survival rates increased post-ICI approval among uninsured individuals (from 16.2% to 28.3%) and individuals with private insurance (from 28.7% to 46.0%) for those with a diagnosis of melanoma, resulting in a widening disparity of 6.1 percentage points (pp) (95% CI, 1.7-10.6 pp) after adjusting for sociodemographic characteristics. Similarly, among people with a diagnosis of NSCLC, the survival disparity between people without insurance and people with private insurance widened to 1.3 pp (95% CI, 0.2-2.3 pp). Survival differences between people with Medicaid and those with private insurance did not change significantly with the introduction of ICIs (DID for melanoma, -1.9 pp [95% CI, -5.6 to 1.8 pp]; DID for NSCLC, 0.4 pp [95% CI, -0.4 to 1.2 pp]; and DID for RCC, -3.8 pp [95% CI, -9.4 to 1.9 pp]). Conclusions and Relevance: This serial cross-sectional study found that the introduction of ICIs was associated with widening survival disparity between people without health insurance and those with private insurance. Policies expanding access to health insurance coverage options and making new treatments more affordable are needed.