Biomarker-driven treatment selection for metastatic breast cancer

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

Not applicable Interventional Washington University School of Medicine · NCT05977036

This study is testing if measuring a specific blood marker can help doctors decide when to change treatments for patients with certain types of advanced breast cancer to improve their chances of staying cancer-free longer.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment65 (estimated)
Ages18 Years and up
SexAll
SponsorWashington University School of Medicine Academic / other
Drugs / interventionschemotherapy
Locations1 site (St Louis, Missouri)
Trial IDNCT05977036 on ClinicalTrials.gov

What this trial studies

This prospective study evaluates the impact of biomarker-driven early therapeutic switching and delayed imaging in patients with HR+ HER2- metastatic or unresectable breast cancer. Patients will start with a CDK4/6 inhibitor and endocrine therapy, with blood samples taken to assess thymidine kinase activity (TKa) at baseline and on day 15 of treatment. If TKa suppression is not observed, patients will switch therapies; if suppression is noted, they will continue treatment and delay imaging scans. The study aims to determine if TKa levels can predict progression-free survival on the initial therapy.

Who should consider this trial

Good fit: Ideal candidates are post-menopausal women diagnosed with HR+ HER2- metastatic or unresectable breast cancer who are starting first-line therapy.

Not a fit: Patients with early-stage breast cancer or those who are not HR+ HER2- may not benefit from this study.

Why it matters

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

How similar studies have performed: Other studies have shown promise in using biomarkers for treatment selection in breast cancer, indicating potential success for this approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria - Patients

* Diagnosis of metastatic or advanced unresectable invasive breast cancer that is hormone receptor-positive (HR+) and HER2-negative.
* Planned to initiate standard of care first-line therapy with FDA-approved endocrine therapy plus CDK4/6 inhibitor for the stated diagnosis at the time of study enrollment. 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.
* Any prior therapy for early stage breast cancer is allowed, including endocrine therapy and chemotherapy.
* Prior receipt of adjuvant CDK 4/6 inhibitor therapy is permitted provided therapy completion occurred \> 12 months prior to study enrollment.
* Presence of RECIST-evaluable disease. Patients with bone-only disease are eligible.
* At least 18 years of age.
* ECOG performance status ≤ 2
* Post-menopausal status, defined as one of the following:

  * Age ≥ 60 years
  * Age \< 60 with intact uterus and amenorrhea for 12 consecutive months or more
  * Status post bilateral oophorectomy, total hysterectomy
  * Pre- or peri-menopausal with suppressed ovarian function by use of GnRH agonist/antagonist or surgical bilateral oophorectomy
* Ability to understand and willingness to sign an IRB approved written informed consent document (or that of legally authorized representative, if applicable).

Exclusion Criteria - Patients

* Receipt of any prior cytotoxic chemotherapy line for metastatic disease. There will be no limit to chemotherapy use in the neoadjuvant or adjuvant setting.
* Patients with a prior or concurrent malignancy are excluded unless that malignancy's natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial.
* Concurrent participation in any investigational therapeutic trial for treatment of metastatic breast cancer.

Eligibility Criteria - Physicians

* Medical Oncologist at Siteman Cancer Center.
* Treating patients with metastatic or advanced unresectable breast cancer.
* Willing to complete Physician Surveys during participation.

Where this trial is running

St Louis, Missouri

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 Metastatic Breast CancerUnresectable Breast CancerER+ HER2- metastatic breast cancerbiomarkersthymidine kinase
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.