Blood tests could reveal hidden resistance in breast cancer

NCT ID NCT07701070

Not yet recruiting Knowledge-focused Sponsor: AstraZeneca Source: ClinicalTrials.gov ↗

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

Summary

This study observes people with a common type of advanced breast cancer (HR+/HER2-) who are already on standard hormone therapy. Researchers use simple blood tests to look for changes in the ESR1 gene, which can make the cancer stop responding to treatment. By tracking these mutations over time, the study aims to better understand how resistance develops and when it might appear.

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 successful, this study could help doctors predict when breast cancer might become resistant to hormone therapy, potentially guiding earlier treatment changes.
What could go wrong: This is an observational study, not a treatment trial, so it does not test a new therapy. The findings may not directly improve patient outcomes.

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

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Conditions

The condition(s) this trial relates to.

breast cancer hormone receptor-positive breast cancer

As listed by the trial registrant

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

ADVANCED BREAST CANCER

Contacts and locations

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Study contacts

Contact

Phone: •••-•••-•••• Email: •••••@•••••

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