Introduction: The use of PD-1/PD-L1 and CTLA-4 checkpoint inhibitors for the treatment of head and neck squamous cell carcinoma (HNSCC) has been an active field of research in recent years. Major clinical trials in this area have primarily recruited subjects from the U.S., Europe, and Asia, with low recruitment among non-White participants. The goal of this project was to conduct a review of the demographic and racial representation in clinical trials of checkpoint inhibitors that recruited subjects from among the U.S. population.
Methods: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Included studies were written in English, included subjects recruited from the U.S., and evaluated therapy with checkpoint inhibitors in subjects with HNSCC. The nasopharynx subsite and pan-tumor studies were excluded. Titles and abstracts were screened, and those that were not a clinical trial or did not include checkpoint inhibitors in HNSCC were excluded. After initial screening, full-text articles were reviewed. Studies that did not report demographic data or did not publish outcomes were excluded. Duplicates were removed. Demographic information was extracted for analysis, including number of participants and reported demographic data on race and ethnicity.
Results: The search resulted in 11,035 studies. Following removal of duplicates, 8,547 references were eligible to screen. After initial screening, 420 articles were selected for full-text review. Thirty articles met inclusion criteria, of which 17 (57%) included demographic data and were included for full analysis (Fig. 1). Included studies had a mean of 218 and median of 59 (range, 10-720) participants. These studies included subjects who reported a non-White race/ethnicity with a mean of 17.5% and median of 16.9% (range, 10.0-35.0) of the study population. Among international trials enrolling subjects from North America, Europe, and/or Asia (n = 8), the mean for non-White participants was 17.7%, with a median of 16.9% (range, 9.6-35.0%). Among studies enrolling only from North American populations (n = 9), the mean for non-White participants was 17.3%, with a median of 14.7% (range, 5.1-28.6%). Recruitment of Black/African American subjects among these North American trials had a mean of 4.10% and a median of 1.7% (range, 0-16.7%). Recruitment of Hispanic/Latinx subjects among these trials was even lower, with a mean of 1.2% and median of 0.0% (range, 0-9.1%). Overall, only one study included more than 30% non-White representation.
Conclusions: Checkpoint inhibitors have been approved for first line treatment of patients with metastatic recurrent HNSCC and have been the focus of many recent clinical trials. Our review suggests that clinical trial participants remain largely White, with limited enrollment of Black and Hispanic participants. Further efforts are needed to recruit patients of color and ensure representation in clinical trials in this important area of HNSCC management.
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