Can a blood test reveal when breast cancer treatment stops working?

NCT ID NCT04660435

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Recruitment status, easiest to join first

Recruiting now This study
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Sep 14, 2026 · Last updated Sep 15, 2026 · Updated 1 time

Summary

Researchers are studying whether blood and tissue samples can show when metastatic breast cancer stops responding to standard first-line treatment with an aromatase inhibitor and a CDK4/6 inhibitor. The study enrolls women with ER-positive, HER2-negative metastatic breast cancer who have not yet received systemic therapy for advanced disease. Participants give blood and tissue samples over time, which researchers analyze for markers like thymidine kinase activity, gene expression patterns, and circulating tumor DNA. The goal is to see if these markers can predict how long treatment keeps cancer from growing.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

What this could lead to
If the markers work, doctors could one day use a simple blood test to spot treatment resistance early and switch therapies sooner.
What could go wrong
This is an observational study, so it will not test a new treatment. The markers may not reliably predict resistance, and the findings may not apply to all patients.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Participants

About 150 people

The number the study aims to enrol. It can still change while the study runs.

Started

Dec 2020

Expected to finish

Dec 2030

An estimate. End dates often move.

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Who is studied

Pre- and post-menopausal patients with luminal (ER-positive and HER2-negative) MBC who have not received prior systemic therapy for MBC, who are candidate to first-line treatment with an aromatase inhibitor and a CDK4/6i as per standard clinical practice. Patients must have evaluable disease according to RECIST 1.1 (either measurable or non-measurable). Patients with bone-only disease will be allowed in a specific sub-cohort, which will comprise 10% of the total sample size.

Ages

Children (under 18), adults (18 to 64) and older adults (65 and over)

Sex

Female participants only

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Women aged 18 years or older, with a diagnosis of metastatic breast cancer 2. ER-positive and HER2-negative disease as assessed locally either on primary tumor tissue or on a biopsy of a metastasis 3. The patient has not received any prior systemic therapy for metastatic breast cancer (may have received prior hormonal therapy or chemotherapy in the neo/adjuvant setting) 4. The patient is candidate to receive first-line therapy with an aromatase inhibitor (AI) and a CDK4/6 inhibitor per local clinical practice 5. The patient must have evaluable disease according to RECIST 1.1 (either measurable or non-measurable). Note: Patients with bone-only disease will be allowed in a specific sub-cohort, which will comprise 10% of the total sample size. 6. Hystologic material from one formalin-fixed, paraffin-embedded (FFPE) tumor block from a diagnostic core or excisional biopsy of a metastatic lesion, taken before study entry must be provided (patients with bone-only disease will be accepted into the trial without a biopsy of the metastatic site). Hystologic material from an additional biopsy (core or excisional) taken at time of disease progression on the study treatment must also be provided, if clinically feasible. When available, hystologic material from an FFPE tumor block from the primary breast cancer must also be submitted. 7. The patient agrees to provide blood samples. at the trial specified time points Exclusion Criteria: 1. Patients with metastatic disease isolated to the central nervous system (CNS) without metastatic involvement of any other site, unless surgical excision of CNS metastasis has been performed and the tumor tissue is available for the study. 2. Previous or current non-breast malignancies within the last 5 years, with the exception of in situ carcinoma of the cervix and/or adequately treated basal cell or squamous cell carcinoma of the skin

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Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

How to take part

Only the study team decides who joins. These are the ways to reach them.

  1. The places running it

    1 site. The list below names each one and where it is.

  2. The official record

    ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

    Open the record ↗

  3. A doctor treating you

    A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Contacts and locations

Locations

  • Hospital Santo Stefano

    RECRUITING

    Prato, Tuscany, 59100, Italy

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