Prediction of severe neutropenia and diarrhoea in breast
cancer patients treated with abemaciclib
by Natansh D. Modi, Ahmad Y. Abuhelwa, Sarah Badaoui, Emily
Shaw, Kiran Shankaran, Ross A. McKinnon, Andrew Rowland, Michael J. Sorich,
Ashley M. Hopkins
The Breast: VOLUME
58, P57-62, AUGUST 01, 2021
Introduction
Neutropenia and diarrhoea are common and potentially serious
adverse events associated with abemaciclib in advanced breast cancer (ABC), and
the risk factors have been minimally explored. The study aimed to develop
clinical prediction tools that allow personalized predictions of neutropenia
and diarrhoea following abemaciclib initiation.
Materials and methods
Data was pooled from MONARCH 1, 2 and 3 trials investigating
abemaciclib. Cox proportional hazard analysis was used to assess the
association between pre-treatment clinicopathological data and grade ≥3
diarrhoea and neutropenia occurring within the first 365 days of abemaciclib
use.
Results
Older age was associated with increased risk of grade ≥3
diarrhoea [HR [95%CI] for age > 70: 1.72 [1.14–2.58];
P = 0.009]. A clinical prediction tool for abemaciclib induced grade
≥3 neutropenia was optimally defined by race, ECOGPS and white blood cell
count. Large discrimination between subgroups was observed; the highest risk
subgroup had a 64% probability of grade ≥3 neutropenia within the first 365
days of abemaciclib (150 mg twice daily) + fulvestrant/NSAI,
compared to 5% for the lowest risk subgroup.
Conclusion
The study identified advanced age as significantly
associated with an increased risk of abemaciclib induced grade ≥ 3
diarrhoea. A clinical prediction tool, defined by race, ECOGPS and
pre-treatment white blood cell count, was able to discriminate subgroups with
significantly different risks of grade ≥3 neutropenia following abemaciclib
initiation. The tool may enable improved interpretation of personalized risks
and the risk-benefit ratio of abemaciclib.
