NCT05977036

BettER: Biomarker Driven Early Therapeutic Selection in Patients With HR+ HER2- Metastatic or Unresectable Breast Cancer

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 65 (estimated)
• Sponsor: Washington University School of Medicine · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

This is a prospective study to assess the impact of biomarker driven, early therapeutic switching and delayed imaging with the incorporation of DiviTum® serum TK1 activity ("DiviTum® TKa") in patients with HR positive, HER-2 negative metastatic or unresectable breast cancer. Patients will receive first-line treatment with a CDK4/6 inhibitor (CDK4/6i) and endocrine therapy. All patients will have blood drawn for thymidine kinase activity (TKa) testing at baseline and at C1D15. Patients who are found to have a lack of TKa suppression at C1D15 will be recommended to switch to an alternative therapy. Patients with suppressed C1D15 TKa levels will continue on CDK4/6i and endocrine therapy until clinical progression. Patients with TKa which remains suppressed will be recommended to delay restaging scans from 24 weeks to 36 weeks. The investigators hypothesize that a patient's TKa level at C1D15 is prognostic for progression-free survival (PFS) on a CDK4/6 inhibitor and early therapeutic switching in patients with a lack of C1D15 TKa suppression will be associated with prolonged PFS.

Conditions

• Metastatic Breast Cancer
• Unresectable Breast Cancer

Interventions

Type	Name	Description
DEVICE	DiviTum® TKa assay	Will be utilized for determination of serum enzymatic activity of TK1 according to the manufacturer's instructions
DRUG	CDK4/6 + Endocrine therapy	FDA-approved endocrine therapy plus CDK4/6 inhibitor. Ribociclib is the preferred CDK4/6 inhibitor. In the event this drug cannot be obtained due to insurance authorization or if there are specific side effect profile concerns from the treating physician, an alternative CDK4/6 inhibitor is allowed.

Timeline

• Start date: 2024-09-25
• Primary completion: 2034-09-30
• Completion: 2034-09-30
• First posted: 2023-08-04
• Last updated: 2025-12-17

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated device study