New pill shows promise in early breast cancer trial

NCT ID NCT05654532

First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This early-stage trial tests an experimental oral drug called AC699 in 100 adults with a common type of advanced breast cancer (ER+/HER2-). The main goals are to find a safe dose and check for side effects. Researchers will also look for signs that the drug can shrink tumors. Participants must have already tried standard treatments without success.

What this could mean

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

Active substance

AC699 (an oral drug)

What this could lead to

If it works, this could point toward a new treatment option for people with advanced ER+/HER2- breast cancer who have run out of standard options.

What could go wrong

This is a very early (Phase 1) trial, so the main goal is safety, not effectiveness. The drug may not shrink tumors or could cause side effects. Only 100 people are enrolled, so results may not apply to everyone.

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 estrogen-receptor positive breast cancer 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

  • Site 01

    Nashville, Tennessee, 37203, United States

  • Site 02

    Sarasota, Florida, 34232, United States

  • Site 03

    Houston, Texas, 77030, United States

  • Site 04

    Vancouver, Washington, 98684, United States

  • Site 05

    Norfolk, Virginia, 23502, United States

  • Site 06

    Rockville, Maryland, 21044, United States

  • Site 07

    Orlando, Florida, 32746, United States

  • Site 08

    Denver, Colorado, 80218, United States

  • Site 09

    San Antonio, Texas, 78240, United States