[Risk Factors for Dose Reduction in Patients Receiving Abemaciclib-A Multicenter Retrospective Study].

Area of Science:

• Oncology
• Pharmacology
• Clinical Medicine

Background:

• Abemaciclib is a CDK4/6 inhibitor for HR+/HER2- breast cancer.
• Adverse events like diarrhea and neutropenia can necessitate dose reductions.
• Dose reductions may impact treatment efficacy and patient prognosis.

Purpose of the Study:

• To identify risk factors for abemaciclib dose reduction due to adverse events.
• To analyze patient characteristics associated with decreased abemaciclib treatment intensity.

Main Methods:

• Retrospective study of 73 breast cancer patients treated with abemaciclib (Dec 2018-Dec 2022).
• Logistic regression analysis to identify risk factors for dose reduction.
• Comparison between standard dose and dose reduction groups.

Main Results:

• 47.9% of patients required dose reduction, most commonly for diarrhea and neutropenia.
• Multivariate analysis identified age ≥65 years (OR: 4.84) and baseline neutrophil count <3,660/μL (OR: 5.24) as significant risk factors.
• Patients aged 65+ and those with lower baseline neutrophils were significantly more likely to have their abemaciclib dose reduced.

Conclusions:

• Age 65 years or older and baseline neutrophil count ≤3,660/μL are associated with increased risk of abemaciclib dose reduction.
• Further research is needed to evaluate the impact of dose reduction on treatment outcomes and duration.