New hope for breast cancer: early trial of H3B-6545 in japanese women

NCT ID NCT04568902

Completed Disease control Sponsor: Eisai Co., Ltd. Source: ClinicalTrials.gov ↗

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.

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

Get updates

Get notified about this study

Sign up to get updates when this study changes or when new studies for BREAST NEOPLASMS are added.

Our safety recommendation!

By submitting, you agree to our Terms of use

Conditions

The condition(s) this trial relates to.

breast neoplasm hormone receptor-positive breast cancer

As listed by the trial registrant

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

BREAST NEOPLASMS

Contacts and locations

Locations

Eisai Trial Site 1

Kōtoku, Japan
Eisai Trial Site 2

Chūōku, Japan

More trials for these conditions

Other studies related to the condition(s) this trial covers.