In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 37, No. 15_suppl ( 2019-05-20), p. 1042-1042
Abstract:
1042 Background: Few real-world studies have characterized the frequency of genomic alterations of MBC tumors. Data characterizing alterations before and after treatment containing a CDK4 & 6 inhibitor (CDK4 & 6i) are similarly limited. We explore the genomic landscape of HR+/HER2- MBC tumors from patients (pts) treated with a CDK4 & 6i in order to characterize potential mechanisms underlying sensitivity and resistance. Methods: NGS results of tumor and liquid biopsies obtained from 130 pts with estrogen receptor (ER+)/progesterone receptor (PR+)/HER2- MBC between Jan 2008 to Sept 2016 were analyzed. All pts received therapy containing a CDK4 & 6i for MBC at a community cancer network and had NGS results available before and/or after exposure to CDK4 & 6i. Samples were classified as sensitive (n = 69; duration of therapy ≥6 mo) or resistant (n = 61; duration of therapy 〈 6 mo). The frequency of genomic alterations with likely or known significance including short variants, indels, copy number variants, and fusions were characterized. Results: Alterations in 215 unique genes were identified from the NGS results; PIK3CA, TP53, ESR1, CCND1, and FGFR1 were the most frequently altered genes. Select alterations in ESR1 (n = 21 vs 9) and RAD21 (n = 5 vs 0) were more frequent after exposure to CDK4 & 6i. In NGS obtained before exposure to CDK4 & 6i, alterations in select genes including RB1, MDM2, AURKA, and MYC were more frequent in the resistant samples, whereas ARID1A alterations were more frequent in sensitive samples. Of the 6 pts with paired NGS samples pre- and post-CDK4 & 6i treatment, alterations in MYC, CDKN2A, PIK3CA, BRCA1, or RB1 were acquired in 3 pts. Conclusions: Based on real-world data, this study describes the genomic landscape of ER+/PR+/HER2- MBC tumors from pts treated with CDK4 & 6i and identifies potential mechanisms underlying sensitivity and resistance to this new class of drugs. Further evaluation in larger datasets is warranted. Data inclusive of other ER/PR subtypes will be presented.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2019.37.15_suppl.1042
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2019
detail.hit.zdb_id:
2005181-5
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