Abstract P4-06-11: Pathologic Complete Response in Triple Negative Breast Cancer of Black vs White Patients in the Post-Keynote 522 Era
Authors: Sheen Melanie , Chung Victoria , Maini Ruby , Duggan Michael , Levy Julia 
Published: March 2023

Pathologic Complete Response in Triple Negative Breast Cancer of Black vs White Patients in the Post-Keynote 522 Era Melanie Sheen MD, Victoria Chung DO, Ruby Maini MD, Michael Duggan BS, Julia Levy BS Background Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer that lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) gene amplification. Women with TNBC have worse survival outcomes and increased rates of relapse and distant metastasis as compared to women with non-TNBC. Treatment of TNBC has recently been focused on neoadjuvant chemotherapy (NACT) with a goal of achieving a pathologic complete response (pCR) which is associated with longer event-free survival and overall survival. The KEYNOTE-522 trial was presented at the San Antonio Breast Cancer Symposium in December 2019 and found that patients who received pembrolizumab, an anti–programmed death 1 (PD-1) monoclonal antibody, plus NACT were more likely to achieve pCR than women who received placebo plus NACT. On July 26, 2021, the FDA approved the use of pembrolizumab in combination with NACT for high risk, early stage TNBC. KEYNOTE-522 did not collect race as a baseline demographic characteristic, and since TNBC disproportionately affects younger women and Black women, confirming the efficacy of achieving pCR in these groups is essential. Further investigation of the factors that may contribute to achieving pCR in women treated with pembrolizumab for TNBC is warranted. We set out to perform a retrospective analysis examining the rates of pCR in Black versus White patients with TNBC since the initial revelation of the KEYNOTE-522 data. Methods This retrospective chart review of a regional health care network included patients who had been diagnosed with Stage II/III TNBC, documented race as Black/African-American or White, and received treatment with pembrolizumab in the NACT setting. Exclusion criteria included ER-positivity, PR-positivity, HER2-positivity, or unknown receptor status, no pembrolizumab in the neoadjuvant setting, absence of documented race, and age &lt; 18 years-old. Data was collected using Epic SlicerDicer program. Results 118 patients met inclusion criteria. 59 (50.0%) were Black/African American, 59 (50.0%) were white. There were 57 (48.3%) patients who had pCR status identified through pathology reports while the remaining 61 (51.7%) are still undergoing NACT awaiting surgery. 34 Black women and 17 white women have not had surgery yet. Of women who underwent surgery, 12 Black women achieved pCR compared to 15 White women. 13 Black women and 16 White women did not have pCR Discussion Analysis of the data demonstrates an equal number of Black and White women receiving NACT with pembrolizumab. Of those women, there was relatively equal number of pCR between Black and White women. This data shows no appreciable difference in outcomes of Black and White women in terms of response to therapy. Conclusion Given the known association of pCR with increased survival, pembrolizumab should be considered in the treatment regimen for both Black and White women with stage II/III TNBC. This retrospective study is limited by a small patient population. Continued data collection is underway and will be updated.

Citation Format: Melanie Sheen, Victoria Chung, Ruby Maini, Michael Duggan, Julia Levy. Pathologic Complete Response in Triple Negative Breast Cancer of Black vs White Patients in the Post-Keynote 522 Era [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-06-11.