New hope for breast cancer: early trial of H3B-6545 in japanese women
NCT ID NCT04568902
First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This early-phase study tested a new oral drug called H3B-6545 in 33 Japanese women with a common type of breast cancer (ER-positive, HER2-negative). The main goal was to see if the drug is safe and tolerable, and to find the right dose for Japanese patients. Participants had already tried at least two prior hormone therapies.
What this could mean
Our plain-language read of the trial. This is informational only — not medical advice or a prediction.
Active substance
H3B-6545 oral tablets
What this could lead to
If successful, this could lead to a new treatment option for Japanese women with ER-positive, HER2-negative breast cancer.
What could go wrong
This is an early Phase 1 trial with only 33 participants, focused on safety and dosing, not effectiveness. The drug may not work or could cause side effects like rash or liver issues.
Disclaimer
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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.
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.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
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Locations
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Eisai Trial Site 1
Kōtoku, Japan
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Eisai Trial Site 2
Chūōku, Japan