Abstract PO3-02-02: A prospective, international, observational, real-world evidence database, and collaborative platform for Investigator-Initiated Studies in Early-Stage Breast Cancer tested with MammaPrint and BluePrint– the FLEX Study

Abstract TIPS SABCS 2023 A prospective, international, observational, real-world evidence database, and collaborative platform for Investigator-Initiated Studies in Early-Stage Breast Cancer tested with MammaPrint and BluePrint– the FLEX Study Background: Clinical trials have been an invaluable tool in providing improvements in the discovery, treatment, and quality of life for various diseases and disorders including breast cancer, which impacts millions of people each year. The MammaPrint 70-gene assay along with BluePrint 80-gene subtype analysis are tools to provide such improvements in treatment planning. Historically, patient trial populations have not been racially diverse. Current efforts are focused on improving diversity and inclusion to promote efficacy and health equity across all races/ethnicities. Given recent publications supporting the ability of MammaPrint and BluePrint to identify genomic differences in outcomes of black women with breast cancer, the ongoing multi-center FLEX trial (NCT03053193) has proven to be an unparalleled source for improvement in breast cancer care. With a target of 30,000 enrolled patients, the collaborative research network within FLEX will use MammaPrint, BluePrint, full transcriptome, and clinical data to explore clinical and genomic differences in (sub)populations of interest to promote and advance precision medicine for patients with early-stage breast cancer. Methods: FLEX is the first of its kind to link clinical data with full transcriptome data. It is a prospective, observational trial that enrolls patients who are ≥ 18 years old with histologically proven stage I-III breast cancer with up to 3 positive lymph nodes. Patient eligibility for study enrollment include standard of care MammaPrint testing with or without BluePrint and consent to clinically annotated full transcriptome data collection. The study’s infrastructure facilitates the generation of hypotheses for targeted sub-studies that are important for breast cancer management. The FLEX network fosters collaboration with 99 active sites, including Canada, Greece, and Israel. All proposed substudies are vetted and approved by both internal and external research and scientific review committees. Since launching in April 2017, 13,547 patients have been enrolled including those who have been historically underrepresented in trials (Black n =1032; Latin n= 373; AAPI n =276), 43 investigator initiated sub-studies have been approved and are in progress on a varied number of approaches like MammaPrint/Blueprint clinical utilities, racial disparities, neoadjuvant treatment planning in ER+, and or HER2+ breast cancer with 31 abstracts accepted in national and international congresses. Five ongoing sub-studies within FLEX address differences in underlying biology and treatment response/management among Black, Latina, and Asian American patients with early-stage breast cancer. These studies provide a broader understanding of how differential gene expression patterns, identified with MammaPrint and BluePrint, are unique to racial/ethnic groups and can impact treatment outcomes. Overall, the FLEX study strives to use MammaPrint, BluePrint, and newly developed immune signature, ImPrint, along with full transcriptome data to improve precision medicine in early-stage breast cancer. Citation Format: JJ Alberty-Oller, Lee Riley, Laila Samiian, Sarah Thayer, Olexiy Aseyev, Karen Tedesco, Victoria Poillucci, William Audeh, Danijela Jelovac, Joyce O'Shaughnessy. A prospective, international, observational, real-world evidence database, and collaborative platform for Investigator-Initiated Studies in Early-Stage Breast Cancer tested with MammaPrint and BluePrint– the FLEX Study abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-02-02.