Dose reduction and discontinuation due to the combination of CDK4/6 inhibitors and endocrine drugs: a systematic review and meta-analysis

With the widespread use of CDK4/6 inhibitors, the number of discontinuations and reductions due to adverse events is increasing. Therefore, we examined the risk of dose reduction, discontinuation, and occurrence of serious adverse events and death due to adverse events when CDK4/6 inhibitors are combined with endocrine drugs.

We searched English-language articles published up to February 10, 2024, using RR values (risk ratio) to indicate the risk of discontinuation, dose reduction, death, and the risk of serious adverse events.

When CDK4/6 inhibitors were used in combination with endocrine drugs, abemaciclib resulted in the highest risk of discontinuation, dose reduction, and serious adverse events. Ribociclib caused the highest risk of death.

When using CDK4/6 inhibitors in the clinical setting, a comprehensive evaluation should be performed to avoid dosage reductions and discontinuations and to choose the most appropriate treatment regimen.