Home › Trials › NCT06686394

Treatment of advanced HER2 positive breast cancer with patritumab deruxtecan and other agents

HERTHENA-Breast-01: A Phase 1b/2, Multicenter, Open-label, Dose-Finding Study to Evaluate the Safety and Antitumor Activity of Patritumab Deruxtecan in Participants With HER2 Positive Unresectable Locally Advanced Breast Cancer or Metastatic Breast Cancer

Phase1; Phase2 Interventional Merck Sharp & Dohme LLC · NCT06686394

This study is testing a new treatment combining patritumab deruxtecan with other cancer drugs to see if it helps people with advanced HER2 positive breast cancer that can't be surgically removed.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment81 (estimated)
Ages18 Years and up
SexAll
SponsorMerck Sharp & Dohme LLC Industry-sponsored
Drugs / interventionstrastuzumab, tucatinib, lapatinib, neratinib, patritumab
Locations17 sites (Boston, Massachusetts and 16 other locations)
Trial IDNCT06686394 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates the efficacy and safety of patritumab deruxtecan in combination with other anticancer agents for patients with HER2 positive breast cancer that is locally advanced and cannot be surgically removed. Participants will receive treatment and be monitored for their cancer's response, including any reduction in tumor size. The study aims to gather data on how well patients tolerate the treatment and the overall effectiveness in managing their condition. The trial will take place across multiple countries, including the USA, Canada, and several others.

Who should consider this trial

Good fit: Ideal candidates include individuals with histologically confirmed HER2 positive locally advanced unresectable or metastatic breast cancer who have received prior anti-HER2 therapies.

Not a fit: Patients with HER2 negative breast cancer or those who have not received prior anti-HER2 therapies may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with advanced HER2 positive breast cancer.

How similar studies have performed: Other studies have shown promise with similar approaches targeting HER2 positive breast cancer, suggesting potential for success in this trial.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

* Has histologically confirmed HER2+ locally advanced unresectable breast cancer or metastatic breast cancer
* Human immunodeficiency virus (HIV)-infected participants must have well-controlled HIV on antiretroviral therapy (ART)
* Participants who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received HBV antiviral therapy for at least 4 weeks, and have undetectable hepatitis B virus (HBV) viral load before allocation
* Participants with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable
* Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1 within 7 days before start of study intervention

Arm 1:

* Has received at least a minimum of 2 and a maximum of 5 prior lines of anti-HER2 therapy in the locally advanced or metastatic setting
* Had disease progression on or after any previous trastuzumab deruxtecan (T-DXd) treatment

Arm 2:

-Has received no more than 5 prior lines of anti-HER2 therapy in the locally advanced or metastatic setting

Arm 3:

-Has received and had disease progression from T-DXd treatment in any setting and a maximum of 3 prior lines of anti-HER2 therapy in the locally advanced or metastatic setting. T-DXd must be the most recent therapy received before enrollment.

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

* Uncontrolled or significant cardiovascular disease
* History of (noninfectious) pneumonitis/interstitial lung disease (ILD) that required steroids or has current pneumonitis/interstitial lung disease
* Has clinically severe respiratory compromise
* Has any history of or evidence of any current leptomeningeal disease
* Has clinically significant corneal disease
* Evidence of ongoing uncontrolled systemic bacterial, fungal, or viral infection
* HIV infected participants with a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease
* Known additional malignancy that is progressing or has required active treatment within the past 3 years
* Evidence of spinal cord compression or brain metastases
* Has an active infection requiring systemic therapy
* Concurrent active HBV and HCV infection
* Has had major surgical procedure (excluding placement of vascular access) less than 28 days

Arm 3 ONLY

\- Has received prior treatment with tucatinib, lapatinib, or neratinib, or any investigational HER2-targeted tyrosine kinase inhibitors in the locally advanced or metastatic setting

Where this trial is running

Boston, Massachusetts and 16 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Breast NeoplasmsBreast Cancer
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.