New breast cancer drug test halted after just 3 patients

NCT ID NCT05128773

First seen Jun 26, 2026 · Last updated Jun 26, 2026

Summary

This study aimed to see if a new drug called amcenestrant could help prevent breast cancer from coming back in people with hormone receptor-positive early breast cancer who had side effects from standard aromatase inhibitor therapy. It was designed to compare amcenestrant against tamoxifen over 5 years of treatment. However, the trial was stopped early after enrolling only 3 participants, so no conclusions can be drawn.

What this could mean

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

Active substance

amcenestrant

What this could lead to

If it worked, amcenestrant could offer a better-tolerated alternative to tamoxifen for preventing breast cancer recurrence in patients who cannot take aromatase inhibitors.

What could go wrong

The trial was terminated early with only 3 participants enrolled, so no meaningful results are available. It is unknown if amcenestrant is effective or safe compared to tamoxifen.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

breast cancer breast neoplasm hormone receptor-positive breast cancer

As listed by the trial registrant

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

Contacts and locations

Locations

  • Investigational Site Number :1521622

    Santiago, Reg Metropolitana de Santiago, Chile

  • Investigational Site Number :1561599

    Haikou, 570311, China