Evaluating progression-free survival in black and white women with triple-negative breast cancer in pooled clinical trials from a synthetic control database (SCD) and real-world electronic medical records (EMR).

e13102 Background: Previous studies have shown a lower survival rate in Black women with breast cancer compared with other ethnic groups, largely explained by the increased incidence of triple negative breast cancer (TNBC). In this study we further explore relative survival by race within a TNBC population. By using pooled clinical trial data, we seek to control for variation in patient assessment on outcomes. We further use a real-world electronic medical records (EMR) data source to compare the representativeness of pooled trial findings to patients receiving care not on trial. Methods: Phase II and III open-label breast cancer studies having completed their primary analysis were selected from the Medidata Enterprise Data Store (MEDS), comprised of over 19,000 historical clinical trials, for de-identified aggregate analyses. The Synthetic Control Database (SCD) for this study contains 749 patients with TNBC enrolled in second line and higher treatment trials between 2010 and 2017. De-identified Oncology EMR data was sourced from the Guardian Research Network (GRN) of integrated delivery systems from 2010 to 2018, and contained 1877 patients. Baseline characteristics were assessed between pooled trial and real-world data cohorts. Patients were stratified by race. Progression-free survival (PFS) was assessed using a Kaplan-Meier analysis. We conducted further analysis to assess the impact of additional factors that may influence the aggressive progression of TNBC response in Black women and TNBC disparity. Factors included, but were not limited to: age, stage at diagnosis, baseline benign neutropenia, Body Mass Index (BMI) and genetic factors (BRCA). Results: The TNBC SCD population was 73.0% White, 6.8% Black, and 20.2% Non-White Non-Black (NWNB). The real-world distribution, by contrast was 79%, 10%, and 11%, respectively, with patients predominantly stage 2 at diagnosis. Median BMI at diagnosis was 28.6, 32.6 and 27.1. Unadjusted progression-free survival (PFS) was directionally lower in Black patients in a Kaplan-Meier assessment with a Median PFS of 105 days vs 144 days for all others. Conclusions: A representative pool of cross trial TNBC patients demonstrated lower PFS in Black patients compared to their non-Black counterparts. Based on these findings, further investigation to explore potential biological and treatment factors associated with racial disparity in TNBC is warranted.