Abstract 210P
Background
The combination of CDK 4/6i and endocrine treatment is the standard first-line treatment in patients with hormone receptor-positive/HER2-negative mBC. It is still unclear whether HER2-low status has a prognostic impact in this patients’ subgroup.
Methods
Data of eligible patients were retrieved within the Italian retrospective/prospective multicentric GIM14/BIOMETA study (NCT02284581). In this analysis, we included patients who received CDK 4/6i in I line. HER2 status was assessed locally on advanced stage biopsy if available and if not, on the primary tumour. Tumour characteristics and survival outcomes [progression-free survival (PFS) and overall survival (OS)] were compared between patients with HER2-low and HER2-zero tumours.
Results
Overall, 701 pts were eligible for this analysis, of whom 531 patients (75.7%) were enrolled in the prospective cohort. 365 pts (52%) had HER2-zero tumours, 336 (48%) had HER2-low tumours. No difference in tumour characteristic were observed between patients with HER2-zero or HER2 low-tumours. After a median follow-up of 24.8 months, no significant differences were found in terms of PFS (median PFS 2.18 years (IQR 1.07-NR) and 2.30 years (IQR 1.01-5.37) in HER2 0 and HER2-low, respectively) (p=0.972) or OS (median OS beyond 5 years for both groups) (p=0.398). Matched advanced stage and primary tumour biopsies were available for 231 subjects. 65 out of 149 HER2-zero primary tumours turned into HER2-low at the advanced stage biopsy. Among 82 HER2-low primary breast cancers, 29 were classified as HER2-zero at the biopsy performed in the metastatic setting. Among those who experienced disease progression, after CDK 4/6i 40% of patients received chemotherapy (more frequently capecitabine or taxane plus bevacizumab), 36% endocrine treatment (the majority exemestane+ everolimus or fulvestrant), 2% PARP inhibitors or alpelisib, and 9% CDK 4/6i beyond progression. In 13% of cases II line data were not reported.
Conclusions
No significant difference in terms of survival outcomes were found between patients affected by HER2-zero and HER2-low breast cancer treated in I line with CDK 4/6i.
Clinical trial identification
NCT02284581, Study Start 2015-11.
Legal entity responsible for the study
Gruppo Italiano Mammella (GIM).
Funding
BIOMETA/GIM14 study has been partially supported by Roche.
Disclosure
C. Molinelli: Financial Interests, Personal, Research Grant: Fondazione Umberto Veronesi; Financial Interests, Personal, Writing Engagements: Lilly; Financial Interests, Personal, Other, Travel sponsor: Gilead. E. Blondeaux: Financial Interests, Institutional, Funding: Gilead. M. De Laurentiis: Financial Interests, Personal, Invited Speaker: Eli Lilly, Menarini; Financial Interests, Personal, Other: Gilead, Roche, AstraZeneca, Novartis, Seagen, Daiichi Sankyo, Pfizer, Genetic, Pierre Fabre, GSK, Exact Sciences, Tomalab, Eisai, MSD; Financial Interests, Personal, Advisory Board: Seagen, Eli Lilly, Novartis, Sanofi Genzyme, Gilead. F. Riccardi: Financial Interests, Personal, Invited Speaker: Roche, AstraZeneca, Eli Lilly, Pfizer, Novartis, Gilead; Financial Interests, Personal, Other: AstraZeneca, Roche, Gilead, Eli Lilly; Financial Interests, Personal, Advisory Board: Roche, Novartis, Eli Lilly, Pfizer, MSD, Pierre Fabre, Sophos, Epionpharma, Gilead, Exact Sciences, AstraZeneca. F. Cognetti: Financial Interests, Personal, Other: Genomic Health, Biolitec Pharma, Pfizer, Abbott, Celgene, GSK, Roche, Bayer, Novartis, Eisai, Merck-Serono, MSD, BMS; Financial Interests, Personal, Invited Speaker: Amgen, Pfizer, AstraZeneca, Boeringher Ingelheim, Takeda, Astella, Eli Lilly, Seagen. G. Arpino: Financial Interests, Personal, Writing Engagements: AstraZeneca; Financial Interests, Personal, Invited Speaker: AstraZeneca, Eli Lilly, Viatris; Financial Interests, Personal, Advisory Board: Daiichi Sankyo, Eisai, Gilead, Exact Sciences, Roche, Seagen. A. Fabi: Financial Interests, Personal, Advisory Board: Roche, Novartis, Eli Lilly, Pfizer, MSD, Pierre Fabre, Eisai, Gilead, Seagen, AstraZeneca, Exact Sciences. F. Puglisi: Financial Interests, Personal, Other: AstraZeneca, Eisai, Daiichi Sankyo, Eli Lilly, Exact Sciences, Gilead, Ipsen, Menarini, MSD, Novartis, Pierre Fabre, Pfizer, Roche, Seagen, Takeda. C. Bighin: Financial Interests, Personal, Other: Daiichi Sankyo, Lilly, Roche, Novartis, Gilead. M. Lambertini: Financial Interests, Personal, Advisory Board: Roche, AstraZeneca, Lilly, Novartis, Pfizer, Exact Sciences, MSD, Seagen, Gilead; Financial Interests, Personal, Invited Speaker: Takeda, Sandoz, Ipsen, Libbs, Knight, Daiichi Sankyo, Lilly, Pfizer, Novartis, Roche; Financial Interests, Personal, Other, Travel grant to attend ASCO 2022: Gilead; Financial Interests, Institutional, Invited Speaker, 2-year research grant paid to my Institution: Gilead. L. Del Mastro: Financial Interests, Personal, Invited Speaker, Educational meeting: Novartis, Symposia, andromeda E20, Vyvamed S.r.l.; Financial Interests, Personal, Invited Speaker, Lecture: Ipsen; Financial Interests, Personal, Advisory Board, Her2+ and TN breast cancer: Roche; Financial Interests, Personal, Invited Speaker, Consultancy for TNBC text: Roche; Financial Interests, Personal, Advisory Board, denosumab: Amgen; Financial Interests, Personal, Advisory Board, Early and metastatic BC: Eli Lilly; Financial Interests, Personal, Invited Speaker, CDK4-6 inhibitors: Eli Lilly; Financial Interests, Personal, Advisory Board, tucatinib: Seagen Int; Financial Interests, Personal, Advisory Board, Oncotype dx: Exact sciences, Havas life; Financial Interests, Personal, Advisory Board, Neratinib: Pierre Fabre; Financial Interests, Personal, Invited Speaker, Internal training: MSD; Financial Interests, Personal, Invited Speaker, Educational meetings: Accademia Nazionale Medicina; Financial Interests, Personal, Invited Speaker, Author for BC text: Pensiero Scientifico Editore; Financial Interests, Personal, Advisory Board, Breast cancer: Uvet; Financial Interests, Personal, Other, Author slide kits and interviews: Think2it; Financial Interests, Personal, Advisory Board, Palbociclib: Pfizer; Financial Interests, Personal, Invited Speaker, Breast cancer: Aristea, Meeting S.r.l.; Financial Interests, Personal, Other, Author slide kits: Forum service; Financial Interests, Personal, Other, Author text about biosimilars: Edizioni Minerva Medica; Financial Interests, Personal, Other, consultant: Kardo S.r.l.; Financial Interests, Personal, Invited Speaker, Breast cancer meetings: Delphi international, Over S.r.l.; Financial Interests, Personal, Invited Speaker: Prex S.r.l., Editree; Financial Interests, Personal, Advisory Board: Uvet, Collage SpA, Daiichi Sankyo, AstraZeneca, Agendia, Gilead, GSK, Eisai, Stemline Menarini; Financial Interests, Personal, Other, Interview: Infomedica S.r.l.; Financial Interests, Personal, Other, Consultant: Sharing progress in cancer care - Switzerland; Financial Interests, Personal, Other, Consultancy: Eli Lilly, Gilead; Financial Interests, Institutional, Funding, National coordinating PI: Roche; Financial Interests, Institutional, Funding, Local PI: AstraZeneca, Roche, Eli Lilly, Daiichi Sankyo, Novella Clinical, Novartis; Financial Interests, Institutional, Invited Speaker: Gilead, Seagen; Financial Interests, Institutional, Research Grant: Pfizer; Non-Financial Interests, Institutional, Product Samples, Genomic Test: FoundationOne. All other authors have declared no conflicts of interest.