^
Association details:
Evidence:
Evidence Level:
Sensitive: C4 – Case Studies
Source:
Title:

Esr1 mutation as a potential predictor of abemaciclib benefit following prior cdk4/6 inhibitor (cdk4/6i) progression in hormone receptor-positive (hr+) metastatic breast cancer (mbc): A translational investigation

Published date:
11/17/2020
Excerpt:
...two patients with ESR1 mutations (in the absence of concurrent driver alterations in RB1, FGFR, CCNE2, and ERBB2) demonstrated progression on palbociclib and sensitivity to abemaciclib...In one patient, cfDNA obtained prior to palbociclib and fulvestrant exposure failed to reveal any ESR1 alteration. Following progression on palbociclib, and prior to sequential exposure to abemaciclib, an ESR1 Y537N alteration was identified. The patient went on to receive 16 months of abemaciclib monotherapy....These results suggest that patients with HR+ MBC, ESR1 mutation, and clinical resistance to anti-estrogen treatment and palbociclib may be candidates for abemaciclib treatment.