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# Adding CDK Inhibitors Helps Some Breast Cancer Treatment: Study
- URL: https://www.fdaweb.com/adding-cdk-inhibitors-helps-some-breast-cancer-treatment-study/
- Published: 2020-11-17T12:00:00.000Z
- Updated: 2026-09-14T16:36:46.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5148097

CDER researchers say they have determined that adding a cyclin-dependent kinase (CDK) 4/6 inhibitor to a hormonal agent appears to show a consistent benefit for all subgroups analyzed in a study of hormone receptor-positive, HER2-negative metastatic breast cancer. An agency online *Regulatory Science Impact Story* [says](https://www.fda.gov/drugs/regulatory-science-research-and-education/use-cyclin-dependent-kinase-46-inhibitor-hormonal-therapy-metastatic-breast-cancer-efficacy-patient?ref=fdaweb.com) the research involved pooled data from seven breast cancer clinical trials for therapies approved before 1/1/19\. The pooled trials covered 4,200 patients, which allowed for a larger patient sample size for each of the subgroups analyzed, compared to the sample size for any single trial alone, the report says.

“The benefit of adding a CDK 4/6 inhibitor to a hormonal agent was consistent across all subgroups,” CDER says, “which provides important information to clinicians and patients for treatment decision-making. This study will also inform the design and analysis of future clinical trials of hormone receptor-positive, HER2-negative metastatic breast cancer.”