396P - Real-world treatment and survival outcomes in previously untreated patients with metastatic triple-negative breast cancer (mTNBC) in the United States (US)

Background

mTNBC is a clinically aggressive disease associated with poor prognosis with a median overall survival (OS) after metastasis of 15.5 mo. Despite improved survival from recent first-line (1L) therapy (Cortes et al. NEJM. 2022), most patients have disease progression. This study aims to describe the unmet need in previously untreated patients with mTNBC in the US.

Methods

This retrospective observational analysis used Flatiron Health de-identified electronic health record data. Pts (aged ≥ 18 years) with mTNBC (defined by American Society of Clinical Oncology/College of American Pathologists guidelines: HER2 IHC0, 1, or 2/ISH-negative; ER/PR negative) who initiated 1L treatment (tx) from January 2011 to May 2022 were included. Pts receiving HER2-targeted or hormone tx, or a clinical trial drug were excluded. Real-world (rw)OS and time to next tx or death (TTNTD) were calculated using Kaplan-Meier method.

Results

The study included 1764 pts (Table). Median time from diagnosis to 1L tx was 0.85 mo. Most pts received CT mono- (46.9%) or combination (36.7%) therapy (Table). Of the 1764 pts, 907 (51%) initiated second (2)L tx (33% had died) and 453 (26%) initiated 3L tx (35% had died). Median rwOS (95% CI) was 11.2 mo (10.7-12.0) with a 1- and 2-year survival rate (95% CI) of 47.5% (45.1-49.9) and 23.9% (21.7-26.1), respectively. Median TTNTD (95% CI) for 1Ltx was 4.3 mo (4.1-4.5). Stratified analyses by year of mBC diagnosis, tx type, and other factors will be presented. Table: 396P

Conclusions

In this rw study, most pts received CT as 1L therapy. Clinical outcomes were poor, and many pts did not receive tx after 1L due to high attrition rates between lines of therapy. These data confirm the unmet need for more efficacious tx options for pts with mTNBC in the 1L setting.

Clinical trial identification

Editorial acknowledgement

Editorial support was provided by Gwendolyn F. Elphick, PhD, of Parexel and funded by Gilead Sciences, Inc.

Legal entity responsible for the study

Gilead Sciences, Inc.

Funding

Gilead Sciences, Inc.

Disclosure

K. Punie: Financial Interests, Institutional, Advisory Board: AstraZeneca, Novartis, Roche, Vifor Pharma, Eli Lilly, Pierre Fabre, McCann Health, Roularta, Teva, Gilead Sciences, Pfizer, Gilead, MSD; Financial Interests, Institutional, Invited Speaker: Pfizer, Roche, Novartis, Eli Lilly, Mundi Pharma, MSD, Medscape; Financial Interests, Institutional, Other, Consultancy: Roche; Financial Interests, Personal, Other, Consultancy: Gilead, Novartis, MSD, Roche; Financial Interests, Personal, Invited Speaker: Sanofi, AstraZeneca, Exact Sciences, Focus Patient, Pfizer, Gilead Sciences; Financial Interests, Personal, Advisory Board: Seagen, AstraZeneca, Pfizer; Financial Interests, Personal, Ownership Interest: Need Inc.; Financial Interests, Institutional, Funding: Sanofi; Financial Interests, Institutional, Trial Chair: MSD; Non-Financial Interests, Other, Committee member: ESMO Young Oncologists Committee; Non-Financial Interests, Leadership Role, Vice President: Belgian Society of Medical Oncology BSMO; Non-Financial Interests, Other, Committee Member: ESMO Resilience Task Force; Non-Financial Interests, Leadership Role: EORTC Breast Cancer Task Force Steering Committee Member; Non-Financial Interests, Institutional, Product Samples, Drug provision for academic research: Gilead Sciences; Non-Financial Interests, Advisory Role: Commission personalized medecine Federal Government Belgium; Non-Financial Interests, Advisory Role, External Scientific Advisor: European Medicine Agency. I. Ntalla: Financial Interests, Personal, Full or part-time Employment: Gilead Sciences; Financial Interests, Personal, Stocks/Shares: Gilead Sciences. D.H. Huynh: Financial Interests, Personal, Full or part-time Employment, Sr. Associate Director Clinical Development Oncology: Gilead Sciences; Financial Interests, Personal, Stocks/Shares: Gilead Sciences. N. Sadetsky: Financial Interests, Personal, Full or part-time Employment: Gilead; Financial Interests, Personal, Stocks/Shares: Gilead, Roche/Genentech. A. Estrin: Financial Interests, Personal, Full or part-time Employment: Aetion, Inc; Financial Interests, Personal, Stocks/Shares: Aetion, Inc; Financial Interests, Institutional, Local PI, Aetion, my employer, received funding from Gilead to conduct this study. I have not personally received funding.: Aetion, Inc. E. Dabrowski: Financial Interests, Institutional, Full or part-time Employment: Aetion, Inc; Financial Interests, Personal, Stocks/Shares: AbbVie Inc.; Financial Interests, Institutional, Local PI, Aetion, my employer, received funding from Gilead to conduct this study. I have not personally have not received funding.: Gilead Sciences, Inc.. N. Sjekloca: Financial Interests, Personal, Stocks/Shares: Gilead Sciences. C. Lai: Financial Interests, Personal, Full or part-time Employment: Gilead Sciences; Financial Interests, Personal, Stocks/Shares: Roche, Gilead Sciences. S.A. Hurvitz: Financial Interests, Personal, Invited Speaker: Clinical Care Options, axis medical, cancer expert now, ICHE, MJH Associates, PER, Primo, Projects in Knowledge, Prova Education, Research to Practice, Ultimate Medical Academy, Vaniam, WebMD, Peer Education, PrecisCA; Financial Interests, Personal, Stocks/Shares, spouse owns: ROM Tech; Financial Interests, Personal, Ownership Interest, spouse: Ideal Implant; Financial Interests, Personal, Royalties, author medical book: McGraw; Financial Interests, Personal, Royalties: Elsevier, Springer, Sage, Wolters Kluwer, Wiley; Financial Interests, Institutional, Local PI: Ambrx, AstraZeneca, Arvinas, Genentech/Roche, Gilead, GSK, Immunomedics, Eli Lilly, Macrogenics, Novartis, Pfizer, OBI Pharma, Pieris, PUMA, Radius, sanofi, Seattle Genetics, Dignitana, Zymeworks, Phoenix Molecular Designs, Ltd, cytomx, Dantari, G1 Therapeutics, Greenwich Life Sciences, Loxo Oncology, orinove, Orum; Financial Interests, Institutional, Coordinating PI: Daiichi Sankyo, Celcuity; Financial Interests, Institutional, Research Grant: Samumed, Ambrx; Financial Interests, Steering Committee Member: Greenwich Life Sciences, Orum; Non-Financial Interests, Principal Investigator: Genentech, Daiichi Sankyo, Seattle Genetics; Non-Financial Interests, Advisory Role: Daiichi Sankyo, Novartis, Ambrx, 4DPharma, Dantari, Macrogenics, Lilly, Artios, Roche, Pyxis, Amgen, Pieris, Arvinas, Immunomedics/Gilead; Non-Financial Interests, Member: ASCO, AACR; Non-Financial Interests, Other, speaker: National Breast Cancer Coalition; Non-Financial Interests, Member, site representative for breast cancer guidelines: National Comprehensive Cancer Network. All other authors have declared no conflicts of interest.