Geographic access to triple negative breast cancer (TNBC) clinical trials: Are trials located near Black women?

Abstract

1111 Background: Despite recent treatment advances, TNBC has a poor prognosis relative to other breast cancer subtypes. Black women in the U.S. are more likely to be diagnosed with TNBC, are diagnosed at more advanced stages, and have higher mortality even after controlling for socioeconomic variables than women of other races. Although clinical trials are essential to improving TNBC treatment, Black women are underrepresented. We investigated the geographic availability of TNBC clinical trials for Black women in the U.S. to elucidate potential trial access limitations. Methods: All trials registered on ClinicalTrials.gov as of 9/30/2024 were queried (N= 510,397). Phase II and III interventional treatment trials in active status in the U.S. including “breast” in the title or disease variable (n =449) were considered. We narrowed results to TNBC trials through keyword searches of title and disease variables (e.g., TNBC, HER2 negative and hormone receptor negative). We tabulated the number of trials per county and supplemented with 5-year population estimates (2018-2022) and county adjacency data from the U.S. Census Bureau to evaluate for geographic and demographic differences in TNBC trial availability. Results: We identified 108 active TNBC trials (58 metastatic [54%], 50 nonmetastatic [46%]), including 87 Phase II (81%) and 21 Phase III (19%). There were 1,230 U.S. study sites, of which 217 had one active TNBC trial (18%), 529 had 2-4 trials (43%), and 484 had ≥5 trials (39%). Most sites had metastatic and nonmetastatic offerings (700, 57%) while 450 sites had only nonmetastatic trials (37%) and 80 had only metastatic trials (7%). State-level differences in trial availability were observed (see Table). For example, 37% of Black and 34% of non-Black women 18+ in Alabama had no TNBC trials in their or neighboring counties while all women 18+ in nine states had a trial available in at least a neighboring county. Conclusions: A geographical analysis of active Phase II and III therapeutic TNBC clinical trials found uneven trial availability across the country. Most study sites had < 5 TNBC trials available; a third of sites had no metastatic trials, suggesting that many women may have difficulty finding an applicable trial even when near to a site. On a national scale, distance does not appear to be a primary reason for disparities in TNBC trial participation for Black and non-Black women. Nevertheless, millions of women live in areas without any trials, therefore expanding geographic reach is a necessary but insufficient approach to improve access. Category (Number of Counties) Black women 18+ in millions (%) Non-Black women 18+ in millions (%) Total in millions (%) Counties with trial (748) 14 (82%) 88 (77%) 102 (78%) Trials only in adjacent county (1452) 2 (12%) 21 (18%)  22 (17%) No trials in county nor adjacently (944) 1 (6%) 6 (5%)  7 (5%) Total (3144) 17 (100%) 115 (100%) 131 (100%)