Abstract 238P
Background
Pts with HR+/HER2– mBC are typically treated with endocrine-based therapies (ET) until ET resistance develops, at which point Tx options are limited to CT-based regimens, and now antibody-drug conjugates (ADC). This real-world study aims to describe Tx patterns in pts with HR+/HER2– mBC treated with CT before the ADC era.
Methods
This retrospective, observational study used the ConcertAI Patient360™ dataset of electronic medical record data of pts from the US. Pts (aged ≥18 years old) with HR+/HER2– mBC and initiating their first CT in the metastatic setting from Jan 2011 - Jun 2021 were included. Time to next Tx or death (TTNTD) was calculated for all pts and for pts subsequently treated with a second, third, and fourth CT. Index date was the start date of each CT.
Results
Pts (N=1545) included were female (99%) and White (76%); median age was 61 years. Most pts (80%) were treated in a community setting; 41%, 19%, and 18% received their first CT in 1L, 2L, and 3L, respectively. Sixty percent and 44% of pts had prior exposure to ET and CDK4/6i in the metastatic setting, respectively. Majority of pts received CT monotherapy across CT lines. Most used agents across CT lines are shown in the table; capecitabine and paclitaxel were most used in earlier lines of CT. Median TTNTD (95% CI) was 6.5 mo (5.9-7.1) in pts treated with first CT, and 6.4 mo (5.9-7.4), 4.6 mo (4.2-5.2), and 3.9 mo (3.5-4.3) in pts subsequently treated with a second (n=886), third (n=480), and fourth CT (n=260), respectively.
Conclusions
In this real-world study, capecitabine and paclitaxel were most commonly used in earlier lines of CT. TTNTD decreased with each subsequent CT received, indicating a high unmet need for more efficacious treatment options for ET-resistant HR+/HER2– mBC. Table: 238P
Use of CT agents in pts with HR+/HER2– mBC
| Treatment type* | 1st CT N=1545 | 2nd CT n=886 | 3rd CT n=480 | 4th CT n=260 |
| Taxanes | ||||
| Paclitaxel | 29% | 35% | 25% | 17% |
| Docetaxel | 7% | 5% | 3% | 4% |
| Anthracyclines | ||||
| Doxorubicin | 11% | 7% | 12% | 11% |
| Epirubicin | <1% | <1% | 1% | <1% |
| Platinum agents | ||||
| Cisplatin | 1% | 1% | <1% | <1% |
| Carboplatin | 6% | 7% | 8% | 8% |
| Pyrimidine analogues | ||||
| Capecitabine | 45% | 30% | 22% | 16% |
| Gemcitabine | 8% | 13% | 18% | 22% |
| Other | ||||
| Eribulin | 3% | 11% | 19% | 20% |
| Vinorelbine | 1% | 4% | 4% | 11% |
*The proportion of pts may add up to greater than 100% as the subgroups are not mutually exclusive. CT, chemotherapy; mBC, metastatic breast cancer; pts, patients.
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, MSD; Financial Interests, Institutional, Other, Consultancy: Roche; Financial Interests, Personal, Other, Consultancy: Gilead, Novartis, MSD, Roche; Financial Interests, Personal, Invited Speaker: AstraZeneca, Sanofi; Financial Interests, Personal, Advisory Board: Seagen; Financial Interests, Institutional, Funding: Sanofi; Non-Financial Interests, Principal Investigator: EORTC 1745-ETF-BCG trial; Non-Financial Interests, Other, Committee member: ESMO Young Oncologists Committee; Non-Financial Interests, Invited Speaker: BSMO; Non-Financial Interests, Other, Committee Member: ESMO Resilience Task Force; Non-Financial Interests, Advisory Role: Commission personalized medecine Federal Government Belgium; Non-Financial Interests, Advisory Role, External Scientific Advisor: European Medicine Agency. K. Jhaveri: Financial Interests, Personal, Advisory Board: Novartis, AstraZeneca, AbbVie, Taiho Oncology, Seattle Genetics, Daiichi Sankyo, Loxo Oncology, Gilead, Blueprint Medicines, Biotheranostics; Financial Interests, Personal, Other, Consultant: Pfizer, Genentech, Sun Pharma Pvt Ltd.; Financial Interests, Institutional, Invited Speaker: Novartis, Pfizer, AstraZeneca, Lilly Pharmaceuticals, Genentech, Zymeworks, Gilead, Puma Biotechnology, Merck Pharmaceuticals; Non-Financial Interests, Leadership Role: Lilly/Loxo Oncology. 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, Daiichi Sankyo, 4D Pharma, ARC Therapeutics; Financial Interests, Personal, Advisory Board, Ad Board participant/consultant: Merck; Financial Interests, Personal, Advisory Board, Ad board participant: Bristol Myers Squibb, Mersana Therapeutics, Ellipses Pharma; Financial Interests, Personal, Other, Steering Committee Member/Consultant: CytomX; Financial Interests, Personal, Other, Consultant: Blueprint Medicines; Financial Interests, Personal, Advisory Board, Advisory Board Participation: Zymeworks; Financial Interests, Personal, Advisory Board, Advisory Board participation: Zentalis, OncXerna, Myovant, Bayer, Zetagen, Infinity Therapeutics, Umoja Biopharma; Financial Interests, Personal, Advisory Board, Advisory board participation: Reveal Genomics; Financial Interests, Personal, Advisory Board, Advisory Board participation/consulting: Menarini/Stemline; Financial Interests, Personal, Other, Consulting: Aadi BioPharma; 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. I. Ntalla: Financial Interests, Personal, Full or part-time Employment: Gilead Sciences, Inc.; Financial Interests, Personal, Stocks/Shares: Gilead Sciences, Inc. A. Shah: Financial Interests, Personal, Full or part-time Employment: Gilead; Financial Interests, Personal, Stocks/Shares: Roche. N. Sjekloca: Financial Interests, Personal, Stocks/Shares: Gilead Sciences. K. Fraeman: Financial Interests, Personal, Full or part-time Employment: Gilead Sciences, Inc. L.A. Carey: Financial Interests, Personal, Royalties, immediate family member-royalty-sharing agreement, investorship interest in licensed IP to startup company, Falcon Therapeutics, that is designing neural stem cell-based therapy for glioblastoma multiforme.: Falcon Therapeutics; Financial Interests, Institutional, Funding, research funding: Syndax, Immunomedics, Novartis, Nanostring Technologies, AbbVie, Seattle Genetics, Veracyte; Non-Financial Interests, Advisory Role, uncompensated relationship - all monies go to UNC. Dr. Carey does not have any signatory authority over any UNC account: sanofi, Novartis, G1 Therapeutics, Genentech/Roche, GlaxoSmithKline, AstraZeneca/ Daiichi Sankyo, Apitude Health, Exact Sciences.