The STOP-HER2 Trial: Outcomes in Patients with HER2+ Metastatic Breast Cancer - Clinical Trial

What is the Purpose of this Study?

We are doing this study to find out if anti-HER2 treatment can be safely stopped in patients with metastatic HER2+ breast cancer who have had an exceptional response to treatment for at least 3 years.

What is the Condition Being Studied?

Metastatic HER2+ breast cancer

Who Can Participate in the Study?

Adults ages 18+ who:

- Are diagnosed with metastatic HER2+ breast cancer

- Have been on first-line anti-HER2 therapy for at least 3 years

- Have not had any disease progression

For more information about who can join this study, please contact the study team at

Age Group

What is Involved?

If you choose to join this study, you will:

- Make a choice to participate in 1 of 2 groups

-- You can continue to receive the anti-HER2 therapy you are taking; OR

-- You can stop taking anti-HER2 therapy

- Have blood draws

- Have imaging scans

- Complete questionnaires

- Give us permission to use your stored tissue samples

Study Details

Full Title
A Phase 2 Study of Stopping Trastuzumab - Outcomes in Patients with HER2+ Metastatic Breast Cancer
Principal Investigator
Medical Oncologist
Protocol Number
IRB: PRO00113523
NCT: NCT05721248
Phase II
Enrollment Status
Open for Enrollment