Abstract PS4-11-22: Molecular characteristics of TNBC and pathologic response to chemoimmunotherapy: a focus on racial disparities

Abstract Background: Triple-negative breast cancer (TNBC) is a high-risk subtype characterized by aggressive clinical behavior with limited targeted therapies. The addition of pembrolizumab to neoadjuvant chemotherapy (NACT) has improved pathologic complete response (pCR) rates in early-stage TNBC. However, racial disparities in outcomes remain, and limited data exist on how these disparities may impact pathologic response to chemoimmunotherapy. Our prior retrospective analysis revealed statistically significant differences in pCR among Black or African-American (AA) women following NACT. This study evaluates genomic differences among TNBC patients treated with a pembrolizumab-based NACT regimen at a regional health system, aiming to identify genetic markers that may predict treatment response and provide insight into observed racial disparities. Methods: Patient records from Ochsner Health, a regional healthcare network, were reviewed to identify individuals with early-stage TNBC treated with pembrolizumab-based NACT from 2020-2024. Exclusion criteria included unknown receptor status and age