Persistent ethnicity-associated disparity in anti-tumor effectiveness of immune checkpoint inhibitors despite equal access

Abstract

We reviewed response to immune checkpoint inhibitors (ICI) of 207 patients with diagnoses of lung or head and neck cancer treated with chemotherapy/ICI combination therapy and ICI monotherapy between 2015 and 2020 at one of three clinical pavilions associated with the Dan L. Duncan Comprehensive Cancer Center at Baylor College of Medicine. Two of these pavilions (Harris Health System and the Michael E. DeBakey Veterans Affairs Medical Center) serve large minority populations and provide equal access to care regardless of means. 174 patients had a diagnosis of lung cancer (non-small cell or small cell) and 33 had a diagnosis of head and neck squamous cell carcinoma (HNSCC). 38% self-identified as Black, 45% as non-Hispanic White, and 18% as Hispanic. The objective response rate (ORR) was similar for lung cancer (35.057%) and HNSCC patients (30.3%) (p=0.894). The ORR for Hispanic and Black patients was lower compared to non-Hispanic White patients (H 27.0%, B 32.5%, W 38.7%; H vs. W p=0.209; B vs. W p=0.398). When considering only patients treated with ICI monotherapy, the ORR for Hispanic patients dropped further to 20.7% while the ORR of Black and non-Hispanic White patients remained about the same (B 29.3% and W 35.9%, H vs. W p=0.133; B vs. W p=0.419). Immune related adverse events were the lowest in the Hispanic population occurring in only 30% of patients compared to 40% of patients in the Black cohort and 50% of the non-Hispanic White cohorts.

Keywords: head and neck cancer; immune checkpoint inhibitors; lung cancer; race.

FIGURE 1

Best overall response. A, ORR data for all patients and by disease category for patients treated with either ICI monotherapy or chemo/ICI combination therapy. B, ORR data for all patients and by disease category for patients treated with ICI monotherapy. C, ORR data for patients with NSCLC stratified by PD-L1 status treated with ICI monotherapy. Only patients for whom PD-L1 was known were included.

FIGURE 2

Best overall response by race/ethnic group. A, ORR data for all patients and by race/ethnic group for patients treated with either ICI monotherapy or chemo/ICI combination therapy. B, ORR data for all patients and by race/ethnic group for patients treated with ICI monotherapy. PR, partial response; SD, stable disease; PD, progressive disease.

FIGURE 3

Best overall response by PD-L1. ORR data by race/ethnic group for patients with NSCLC treated with ICI monotherapy stratified by PD-L1 e50% (A), 1%–49% (B), and 0% (C). PR, partial response; SD, stable disease; PD, progressive disease.

FIGURE 4

Immune-related adverse events (irAE) within the entire treatment cohort. A, Overall irAE rate as a function of race/ethnic group. B, ORR as a function of irAE for the ICI monotherapy cohort. PR, partial response; SD, stable disease; PD, progressive disease.