Experimental HER2 cancer drug trial halted early

NCT ID NCT05514717

Terminated Disease control Sponsor: Day One Biopharmaceuticals, Inc. Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This was an early-phase study testing a new drug called XMT-2056 in people with advanced solid tumors that have a protein called HER2. The trial aimed to find a safe dose and check for side effects. It was terminated early, so the full results are not available.

What this could mean

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

Active substance: XMT-2056 (given intravenously)
What this could lead to: If it had succeeded, this could have pointed toward a new treatment option for advanced HER2-positive cancers.
What could go wrong: The trial was terminated early, so results are limited. It was a very early phase 1 study, so safety and effectiveness were not established.

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

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Conditions

The condition(s) this trial relates to.

colorectal carcinoma gastric cancer HER2 positive breast carcinoma non-small cell lung carcinoma

As listed by the trial registrant

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

HER2-LOW BREAST CANCER HER2-POSITIVE BREAST CANCER HER2-POSITIVE COLORECTAL CANCER HER2-POSITIVE GASTRIC CANCER HER2-POSITIVE NON-SMALL CELL LUNG CANCER HER2-POSITIVE TUMORS

Contacts and locations

Locations

AdventHealth Celebration

Celebration, Florida, 34747, United States
Emory Healthcare, Emory Clinic

Atlanta, Georgia, 30322, United States
Hackensack University Medical Center

Hackensack, New Jersey, 07601, United States
Icahn School of Medicine at Mount Sinai

New York, New York, 10029, United States
Karmanos Cancer Institute

Detroit, Michigan, 48201, United States
Massachusetts General Hospital

Boston, Massachusetts, 02114, United States
Memorial Sloan Kettering Cancer Center

New York, New York, 10065, United States
New York University Medical Oncology Associates

New York, New York, 10016, United States
Stanford University Medical Center

Stanford, California, 94305, United States
Tennessee Oncology, PLLC

Nashville, Tennessee, 37203, United States
The Ohio State University Comprehensive Cancer Center

Columbus, Ohio, 43212, United States
The University of Texas MD Anderson Cancer Center

Houston, Texas, 77030, United States
University of California Los Angeles

Los Angeles, California, 90095, United States
University of South California

Los Angeles, California, 90033, United States

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