NCT05305924

Fulvestrant+Abemaciclib With Run-In of Fulvestrant in Er-Positive, Her2-Negative Metastatic Breast Cancer

Phase II Trial Of Fulvestrant Plus Abemaciclib In Er-Positive, Her2-Negative Metastatic Breast Cancer Immediately After Failure Of A Cdk4/6 Inhibitor

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 28 (estimated)
• Sponsor: The Methodist Hospital Research Institute · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The study will investigate if CDK4/6 inhibitor holiday will reset the cell cycle process to respond to the combination of fulvestrant and abemaciclib, and this approach may represent an effective therapeutic strategy to manage such patients.

Detailed description

Endocrine therapy, including aromatase inhibitor therapy, is the primary treatment for ER-positive metastatic disease. Despite the effectiveness of this treatment, not all patients respond to it and many patients who are initially responsive to the drug, eventually develop resistance to it. The management of patients with ER-positive, HER2-negative metastatic breast cancer who experience disease progression after standard treatment (CDK4/6 inhibitor plus an aromatase inhibitor) is a significant challenge and identification of new therapeutic strategies for this population of patients remains an unmet clinical need. The aim of this research study is to determine if a month delay in the administration of the drug abemaciclib will be more effective than the drugs fulvestrant plus abemaciclib given together from the beginning for the treatment of ER-positive, HER2-negative metastatic breast cancer that has progressed on previous treatment. The study will investigate if a one month drug holiday from the CDK4/6 inhibitor drug, abemaciclib, will restore the body's sensitivity to the drug and make the subsequent treatment of abemaciclib plus fulvestrant more effective. This is a single arm study where patients will receive fulvestrant for 1 month, followed by abemaciclib and fulvestrant every 28 days. The treatment will be administered until disease progression or unacceptable toxicity.

Conditions

• ER-Positive Breast Cancer
• HER2-negative Breast Cancer

Interventions

Type	Name	Description
DRUG	Fulvestrant Run-In	The study is evaluating if a drug holiday (post CDK inhibitors progression) will reset the cell cycle machinery to be responsive to Abemaciclib and Fulvestrant.

Timeline

• Start date: 2021-02-25
• Primary completion: 2026-12-01
• Completion: 2027-12-01
• First posted: 2022-03-31
• Last updated: 2026-01-28

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study