Comparative analysis of Keynote522 treatment outcomes in Hispanic versus non-Hispanic patients with breast cancer: A single tertiary center experience.

e12661 Background: The addition of pembrolizumab to neoadjuvant chemotherapy on the Keynote522 (KN522) clinical trial, changed the standard of care for early stage triple negative breast cancer (TNBC). This regimen demonstrated longer event free survival and higher percentage of patients with pathologic complete responses (pCR). However, limited data exist on the comparative outcomes between Hispanic and non-Hispanic patients in real-world settings as this patient population was likely underrepresented on the original trial. Methods: We conducted a retrospective analysis of patients with early stage TNBC treated on KN522 regimen and undergoing surgery at a single tertiary center from July 2021 to present. Patients were stratified into Hispanic and non-Hispanic ethnicity cohorts. The primary endpoint was pCR rate, and secondary endpoints was incidence of adverse effects (AEs). Results: Among a cohort of 41 patients identified, 26 (63%) were of Hispanic and 15 (37%) were non-Hispanic. The pCR rate was 50% among Hispanic and 53% among non-Hispanic patients (p=0.83). Hispanic patients experienced higher rates of anemia (88% vs. 67%, p=0.06), fatigue (85% vs. 60%, p=0.07), skin rash (46% vs. 27%, p=0.21), and endocrine toxicities (23% vs. 13%, p=0.21). However, Hispanic patient also had fewer hospitalizations (35% vs. 47%, p=0.44), dose-modifications (12% vs. 40%, p=0.53), dose omissions (19% vs. 33%, p=0.31), and showed higher KN522 completion rates (81% vs. 53%, p=0.06). Conclusions: Our findings indicate a comparable pCR rate between Hispanic and non-Hispanic patients with early-stage TNBC receiving KN522 therapy. While Hispanic patients exhibited higher incidences of certain adverse effects, they demonstrated lower rates of hospitalizations, dose modifications, and omissions, alongside a notably higher completion rate of the KN522 regimen. These trends may be attributed to various factors such as genetic predispositions, and potentially differential physiological responses to therapy within this ethnic group. These findings underscore the importance of including minorities, such as Hispanic patients, in clinical trial populations to ensure that treatment outcomes are representative of diverse patient demographics. Table: see text