Abstract 253P
Background
HR+/HER2- mBC treatment has traditionally relied on endocrine therapy (ET) in early lines of treatment. The approval of cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors improved both progression-free (PFS) and overall survival (OS) for these patients (pts). Traditional chemotherapy (CT) is often utilized in later lines of therapy with limited effectiveness, increase in adverse events, and deterioration in quality of life. Here, we assess the unmet need among heavily pretreated HR+/HER2- mBC pts.
Methods
The study is a retrospective, observational study using U.S. oncology electronic medical record data available to ConcertAI through data sharing agreements, and referred to the ConcertAI Patient360™ breast cancer dataset. Definitions and algorithm to create the HR+HER2- cohort were based on NCCN approved treatment. Pts were included after discontinuing at least one CDK4/6 inhibitor and ET prior to starting their second CT in the metastatic setting. The index date is the start of second, third, fourth and fifth CT in the metastatic setting between January 1, 2015, through September 30, 2019 (for second CT) and September 30, 2020 (for all other lines). The outcomes included are OS and PFS (defined as time to next treatment).
Results
Of 4,483 pts identified with HR+/HER2- mBC, 2,704 pts (60%) received at least one CDK 4/6 inhibitor and ET. Of these, 266 pts (10%) received at least one CDK 4/6 inhibitor, ET and at least two CT in the metastatic setting. The rest of the pts (90%) either died or received less than 2 CT in the metastatic setting. Mean age at the beginning of 2nd CT was 59 years. The median OS after initiation of 2, 3, 4 and 5 CT was 13.5 months (CI 10.7-16.3), 9.1 months (CI 7.6-11), 6.8 months (CI 4.6-11) and 7.2 months (CI 2.9-13), respectively. PFS was 7.6 (CI 6.4-9.4) months, 4.8 months (CI 4.1-6.1), 4.2 months (CI 2.4-5.8) and 3.2 months (CI 2-3.9), respectively.
Conclusions
Outcomes for heavily pre-treated pts with HR+/HER2- mBC who have had prior CDK4/6 inhibition remain limited. Novel, efficacious therapies are needed to overcome limitations of existing treatment options in this setting.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Gilead Sciences, Inc.
Funding
Gilead Sciences, Inc.
Disclosure
A.G. Waks: Financial Interests, Institutional, Research Grant: Genentech, Merck, and MacroGenics. M. Gharaibeh, N. Sjekloca, E. Bergamaco, T. MacCannell, A. Shah, I. Ntalla: Financial Interests, Personal, Stocks/Shares: Gilead Sciences. N. Poluparthi, G. Leung: Financial Interests, Personal, Full or part-time Employment: Gilead Sciences. H. Oko-osi: Financial Interests, Personal, Stocks/Shares: Gilead Sciences; Financial Interests, Personal, Other: Gilead Sciences. S.M. Tolaney: Financial Interests, Personal, Advisory Board, Ad Board Participant/Consultant: AstraZeneca, Eli Lilly; Financial Interests, Personal, Advisory Board, Ad board participant/Consultant: Pfizer; Financial Interests, Personal, Advisory Board, Ad board participant/consultant: Novartis, Gilead, Genentech/Roche, Eisai, Sanofi, SeaGen, Daichii Sankyo, 4D Pharma, Puma, ARC Therapeutics; Financial Interests, Personal, Advisory Board, Ad Board participant/consultant: Merck; Financial Interests, Personal, Other, Consultant: Nektar, Nanostring, Athenex, Blueprint Medicines; Financial Interests, Personal, Advisory Board, Ad board participant: Bristol-Myers Squibb, OncoPep, OncoSec, Certara, Mersana Therapeutics, Ellipses Pharma; Financial Interests, Personal, Advisory Board, Ad board participant/consultant/DSMC: Odonate; Financial Interests, Personal, Other, Steering Committee Member/Consultant: CytomX; Financial Interests, Personal, Invited Speaker, Invited speaker for pharma supported educational activity: Chugai Pharmaceuticals; Financial Interests, Personal, Advisory Board, Advisory board participant: G1 Therapeutics; Financial Interests, Personal, Advisory Board, Advisory Board Participation: Zymeworks; Financial Interests, Personal, Advisory Board, Advisory Board participation: Zentalis, OncXerna; Financial Interests, Personal, Advisory Board, Advisory board participation: Reveal Genomics; Financial Interests, Institutional, Funding: AstraZeneca, Eli Lilly, Pfizer, Sanofi, SeaGen, Odonate, Cyclacel, Exelixis, Gilead, Bristol Myers Squibb, Eisai, Merck, Novartis, Nektar, Genentech/Roche; Financial Interests, Personal and Institutional, Invited Speaker: CytomX.