Abstract 313P
Background
PARP inhibitors (PARPi) improves progression free survival among patients(pts) with HER2-ve metastatic breast cancer (MBC) and a BRCA1/2 mutation compared to physician choice of chemotherapy. The objective of this retrospective analysis was to evaluate PARPi treatment in terms of relation to other therapies and survival by breast cancer type and treatment in the real-world setting.
Methods
We utilized a federated network of de-identified health data representing approximately 69 million pt lives available through the TriNetX Platform. We identified 586pts with HER2-ve MBC treated with PARPi. Overall survival (OS) was computed using the Kaplan Meier product limit method. Propensity score matching was performed on all comparisons of OS. Matching variables included age groups, prior genitourinary malignancies, and secondary metastasis location.
Results
Mean age of diagnosis was 55.6 yrs. 56.9% had HR+ve/HER2-ve and 43.1% had TNBC. 78%, 14%, 10% and 5% pts received PARPi in the form of Olaparib, Niraparib, Rucaparib and Talazoparib, respectively. 31%, 51% and ∼30% received PARPi in the 1st line, 2nd line and each subsequent line, respectively. Median OS overall and from date of PARPi was 57m and 23m respectively. Median OS among pts with TNBC and HR+ve/HER2-ve disease was 56m and 58m respectively(p=0.27). Median OS from date of PARPi among pts with TNBC and HR+ve/HER2-ve disease was 18m and 22m respectively(p=0.37). Median OS among pts with HR+ve/HER2-ve who did and did not receive a CDK4/6i was 57m and 69m respectively(p=0.99).Median OS from date of PARPi among pts with HR+ve/HER2-ve who did and did not receive a CDK4/6i was 14m and 23m respectively(p=0.19).52% never received platinum, 12% received platinum after PARPi, and 34% received PARPi following a platinum. No difference in OS among pts who did and did not receive platinum (HR 0.93, 95% CI 0.69-1.31, p=0.63). 27pts with TNBC received immunotherapy (IO) and chemotherapy of whom 62% received a PARPi prior to IO and 39% received PARPi after IO therapy.
Conclusions
We report OS results among pts with HER2-ve MBC who receive PARPi similar to that reported in trials. Interestingly OS among pts with TNBC and HR+ve/HER2-ve who receive PARPi are similar. In community practice there is a trend towards using PARPi prior to IO among pts with TNBC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
TriNetX, LLC.
Funding
Has not received any funding.
Disclosure
S. Dawood: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Invited Speaker: BMS; Financial Interests, Personal, Invited Speaker: Pfizer; Financial Interests, Personal, Invited Speaker: Lilly; Financial Interests, Personal, Invited Speaker: AstraZeneca; Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Advisory Board: Lilly; Financial Interests, Institutional, Research Grant: MSD; Non-Financial Interests, Member: ASCO. K. Brzozowski: Other, employee: TriNetX, LLC.