Assessing blood test for optimal CDK4/6 inhibitor levels in metastatic breast cancer

Use of DiviTum-TKa as a Biomarker Assay for CDK4/6 Inhibitor Medication Compliance and Drug-Drug Interaction Assessment in ER/PR Positive Metastatic Breast Cancer

Not applicable Interventional Yale University · NCT06572800

This study is testing a new blood test to see if it can help people with advanced hormone-positive breast cancer get the right amount of their medication to improve their treatment outcomes.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment50 (estimated)
Ages18 Years and up
SexFemale
SponsorYale University Academic / other
Locations18 sites (Derby, Connecticut and 17 other locations)
Trial IDNCT06572800 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the effectiveness of a blood test developed by DiviTum to identify optimal levels of CDK4/6 inhibitor medications in patients with metastatic hormone-positive breast cancer. The study aims to improve patient outcomes by counseling participants on medication compliance and adjusting for potential drug-drug interactions. Blood samples will be collected at various points during treatment to monitor CDK4/6 inhibitor response and correlate it with thymidine kinase activity levels. The trial will also compare clinical benefit rates and progression-free survival between patients with optimal and sub-optimal responses to treatment.

Who should consider this trial

Good fit: Ideal candidates include adults with histologically confirmed metastatic ER-positive and HER2-negative breast cancer who are starting CDK4/6 inhibitor therapy.

Not a fit: Patients without evidence of metastatic disease or those who have previously received CDK4/6 inhibitors will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to more effective personalized treatment strategies for patients with metastatic breast cancer.

How similar studies have performed: Other studies have shown promise in optimizing treatment through biomarker-guided approaches, making this a potentially impactful continuation of that research.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Participants must have histologically confirmed metastatic ER-positive (\> 10%), PR-positive or PR-negative, and HER2-negative (0 by immunohistochemistry \[IHC\] or if +1 or +2 by IHC, not amplified by fluorescence in situ hybridization \[FISH\]) breast cancer; ER positivity, PR positivity, and HER2 negativity as per the 2018 joint American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines.
* Participants must be starting CDK4/6 inhibitor and endocrine therapy as part of first-line therapy per standard of care and be previously CDK4/6 inhibitor-naïve.
* Participants must be enrolled prior to starting CDK4/6 inhibitor therapy.
* Participants must be ≥ 18 years of age.
* Participants must have an Eastern Cooperative Oncology Group (ECOG) Performance Status \< 3.
* Willing and able to provide written informed consent for the trial.

Exclusion Criteria:

* Participants without evidence of metastatic disease prior to registration.
* Participants with prior use of CDK4/6 inhibitor therapy.
* Participants who are unable to provide informed consent for the trial.

Where this trial is running

Derby, Connecticut and 17 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Anatomic Stage IV Breast Cancer AJCC v8Metastatic HER2-Negative Breast Carcinoma
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.