LAUSR

125 Background: Racial disparities may exist at many levels in the health care system; in oncology, yet little is known about racial disparities in biomarker testing and clinical trial enrollment among patients with mCRC. This study was designed to explore racial differences in comprehensive biomarker testing and clinical trial enrollment in the US using a large real-world database. Methods: This retrospective observational study utilized the Flatiron Health electronic health records database, which includes longitudinal data from patients diagnosed with mCRC. Patients with mCRC were eligible for this study if they had evidence of systemic therapy from 1/1/2017 through 10/30/2020 and were alive for at least 120 days after metastatic diagnosis. Unadjusted analyses summarized differences in biomarker testing and clinical trial enrollment between White and Black race, adjusted regression analyses were conducted using all baseline variables as covariates. These data are de-identified and are not considered human subjects research in accordance with the US Code of Federal Regulations (45 CFR Part 46). Results: A total of 7,879 patients were eligible: 4,803 (61.0%) were White and 838 (10.6%) were Black. Comprehensive testing by next-generation sequencing (NGS) was received by 51.6% and 41.8% of patients who were White and Black, respectively (p < 0.0001). There was no significant difference in clinical trial participation across all lines of therapy (2.9%, White and 2.9% Black). There was a statistically significant relationship between NGS-based testing and clinical trial enrollment (p < 0.0001), however, race was not identified a moderating factor in this relationship in adjusted regression analyses. The receipt of molecularly-targeted therapy was comparable between both races (11.9% and 9.7% for White and Black, respectively; p = 0.06). Patients received FOLFOX+bevacizumab most commonly in the first line (34.3% White; 40.5% Black), all other regimens were within 2 percentage points between racial groups. Targeted agents were each used by less than 7.4% of the study population. Conclusions: The use of NGS-based testing is significantly different by race in this database. The significant relationship between NGS testing and clinical trial enrollment at any time in the database did not appear to be moderated by race; however, descriptive analyses suggest that the ongoing analyses by line of therapy and considering timing of testing may better quantify these relationships. These data may not be generalizable to the entire US population as they are obtained from a single database that is limited to practices using this EHR system.