🏛️ Verified NIH Record • Updated 2026-07-02

Treatment Monitoring of Patients Receiving CDK 4/6 Inhibitors for Hormone Receptor (HR) Positive, HER2 Negative Metastatic Breast Cancer (MBC) With or Without the Addition of DiviTum® Serum Thymidine Kinase 1 (TK1) Activity Testing (NCT04968964)

TK IMPACT: Treatment Monitoring of Patients Receiving CDK 4/6 Inhibitors for Hormone Receptor (HR) Positive, HER2 Negative Metastatic Breast Cancer (MBC) With or Without the Addition of DiviTum® Serum Thymidine Kinase 1 (TK1) Activity Testing: Physician Decision Impact Study

🟢 Recruiting Observational / Diagnostic ⚙️ Medical Device Protocol Sponsor: Washington University School of Medicine

🩺 Plain-English Summary (8th-Grade Level)

Historically, serial testing of patients with metastatic breast cancer has included a combination of physical exam, symptom evaluation, laboratory testing, and imaging. Circulating tumor biomarkers are sometimes also incorporated. Frequent testing with numerous diagnostics at each time point is a significant burden to patients and to healthcare systems. The DiviTum® TKa assay measures TK1 activity. Numerous studies have illustrated the prognostic nature of plasma or serum TK1 activity level in metastatic cancer. The investigators hypothesize that the incorporation of data from DiviTum® TKa measurement into the treatment monitoring schema will be associated with physician desire to change the near-term usage and/or timing of other routine restaging tests, including either standard tumor imaging or tumor marker testing. Given the relatively low rate of disease progression in this first-line population, it is expected that most of this change will be an intended reduction in scheduling of routine treatment surveillance testing with increase in intervals of subsequent tumor restaging imaging by at least 4 weeks. Secondarily, the consequences of rescheduling of routine surveillance testing may ultimately result in an absolute reduction in the number of some tests used during the time period examined.

Who can join: Review the eligibility criteria below.

Location: Washington University School of Medicine — St Louis, Missouri

Age range: 18 Years

🧪 Interventions in This Study

📋 "Do I Qualify?" — 1-Minute Self Screener

Instant Checklist

Full eligibility criteria are available on the official NIH protocol. View the criteria ↗

📍 All Participating Trial Locations (1 Sites)

  • Washington University School of Medicine — St Louis, Missouri

📞 Contact the Study Coordinator

Phone: (314) 273-3022

Email: nbagegni@wustl.edu

Coordinator details come directly from the registered NIH protocol. Confirm the study is still recruiting before traveling.

💰 Cost, Insurance & Patient Rights

  • 100% Free Items: The investigational treatment and protocol-required procedures are supplied at zero cost by the sponsor.
  • Routine Patient Care: Under federal law (ACA § 2709) and many state statutes, routine care costs are covered during participation.
  • Voluntary Participation: You may withdraw at any time without affecting your standard medical care.

Explore by condition: All Breast Cancer clinical trials

💡 How to Participate

  1. Check the checklist above to see if you may qualify.
  2. Contact the study coordinator using the phone/email above.
  3. Ask about the visit schedule, what is covered at no cost, and any travel support.
  4. Confirm with your own doctor before making a decision.
🏛️ View Official NIH Record ↗