Recruiting

How Well a Hormone Therapy Drug Works for Advanced Breast Cancer

Plain-English translation of NCT05452213 on ClinicalTrials.gov ↗ · Source last updated April 2023 · Translation generated June 2026 · How we translate trials

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Phase 4 — The treatment has already been approved. Researchers are tracking how it works in a large number of people over time.

What is this trial?

This is a large study of 1,000 women with advanced breast cancer that has spread but is sensitive to hormones. You would receive , a medication that works with hormone therapy to slow cancer growth. Researchers will track how well the medication works, how long you stay healthy, and what side effects you experience—plus collect blood and tissue samples to understand why the treatment works better for some patients than others.

This medication has shown promise for advanced hormone-sensitive breast cancer, but doctors want to understand it better in real-world treatment—including who benefits most, how long benefits last, and what biological markers might predict success or resistance to the treatment.

Do you qualify?

You likely qualify if…

you are a woman aged 18 or older
you have been diagnosed with advanced or metastatic breast cancer that cannot be cured with surgery or radiation alone
your cancer is hormone receptor-positive (sensitive to hormones) and HER2-negative (a specific type of breast cancer)
your doctor believes you are a good candidate for ribociclib plus hormone therapy as your first treatment for advanced disease
you have a normal heart rhythm (QT interval less than 450 ms) and adequate organ function
you are willing to use effective birth control during and for 21 days after treatment

You likely don't qualify if…

you are pregnant or breastfeeding
you have a history of long QT syndrome or serious heart disease, including recent heart attack or unstable angina
you have a known allergy to ribociclib or to soy or peanuts
you have an active serious infection (bacterial, fungal, or viral) that requires treatment at the time you would start the study
you have untreated HIV, hepatitis B, or hepatitis C

What participation looks like

You would take as a pill combined with your regular hormone therapy at one of 75 hospitals or clinics across Germany. You will have regular clinic visits for check-ups, blood tests, and scans to measure how well the treatment is working and monitor for side effects. Doctors will also collect blood and tissue samples before, during, and after treatment to study biological markers that might explain why the treatment works differently for different patients. The study tracks your progress for at least 12 months, and you may continue the medication as long as it is helping and you are tolerating it well.

AI-generated summary from trial data · Jun 24, 2026 · Not medical advice

Trial locations(52 sites)

Germany

Department of Gynecology and Obstetrics, Erlangen University Hospital, Erlangen, Bavaria

Department of Gynecology and Obstetrics, University Medicine Mainz, Mainz, Hesse

Department for Gynecology and Obstetrics, Marienhospital Bottrop gGmbH, Bottrop, North Rhine-Westphalia

Klinikum St Marien Amberg, Amberg

Onkologie Aschaffenburg, Hämato-Onkologische Schwerpunktpraxis am Klinikum Aschaffenburg, Aschaffenburg