Institutional review of African American (AA) patients with metastatic triple-negative breast cancer.

Abstract

e13059 Background: Atezolizumab+ Abraxane (Ate+Abx) was approved as 1st line treatment in metastatic TNBC based on IMPASSION (IM) 130 trial and was subsequently withdrawn per IM131 trial. Treatment of mTNBC remains challenging. Pembrolizumab with chemotherapy received accelerated approval based on Keynote-355. Poor outcomes among AA patients (pts) are linked to biological differences, BRCA1/2 mutations, obesity, and socioeconomic barriers. In TNBC clinical trials, AA pts continue to be underrepresented, e.g., 5.8% (26) in IM130 and 4.9% (21) in IM131. Our cancer center sees over 300 new BC pts a year, and at least 50% identify as AA. Here we examine our institutional experience. Methods: IRB-approved retrospective database search was conducted between 01/01/2019- 04/16/2021 to identify 11 pts treated with Ate+Abx for mTNBC at Medstar Washington Hospital Center, DC. Demographic variables manually extracted were age, BMI, insurance type and outcomes. Results: 10/11 (91%) pts were AA with lines of therapy ranging 1-6. 20% (2/10) showed partial response (PR) on 3-month (M) interval imaging per the RECIST 1.1 scoring. PD occurred in 6/10 (60%) of pts, although PD-L1 was positive in 90% (9/10) pts. Time to progression (TTP) was 1-7 M (median 3M) compared to TTP of 5.59 to 7.46M (median 7.16M) for all races in the IM130 study. Autoimmune colitis, peripheral neuropathy, and fatigue were notable adverse effects (AEs). 2/10 (20%) pts discontinued treatment due to AEs. Colitis and neuropathy in IM130 were <1%. Mean age at drug initiation was 52.2 vs. 55 years in IM130, indicating earlier onset of mTNBC in the AA population. Conclusions: Trends of higher PD and earlier TTP were noted in our AA pts. Young age at metastasis, high number of previous lines of therapy, high number of metastatic sites, and obesity were noted amongst our AA mTNBC pts. Positive PD-L1, BRCA mutations, metastatic sites, BMI, or insurance type did not correlate with outcomes. Pts with PR vs. PD were not different in terms of insurance, metastasis sites, and BMI. Differences in AEs are noted; however, the small pt population size and lack of a control group are limitations. While the FDA has withdrawn Ate from trials for mTNBC, this study suggests a need for more AA pts to be included in clinical trials for TNBC. Lack of health care access, insufficient education, inadequate recruitment, and distrust of the medical system are contributing factors that require continued efforts.[Table: see text]