UPCC 21123 A Global, Phase 2 Study of ARX788 in HER2-positive Metastatic Breast Cancer Patients who were Previously Treated with T-DXd

Study of a Medication for HER2-positive Metastatic Breast Cancer

Enrolling By Invitation
18 years or above
All
Phase 2
72 participants needed
1 Location

Brief description of study

A Global, Phase 2 Study of ARX788 in HER2-positive Metastatic Breast Cancer Patients who were previously treated with T-DXd

Detailed description of study

A Global, Single Arm, Phase 2 Study of ARX788 in HER2-positive Metastatic Breast Cancer Patients who were previously treated with T-DXd. The ARX788 will be administered every 3 weeks (Q3W) intravenous (IV) infusion.

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: HER2 Positive Metastatic Breast Cancer
  • Age: 18 years or above
  • Gender: All

Key Inclusion Criteria:

  • Age ≥ 18 years and older
  • Life expectancy ≥ 6 months
  • Unresectable or metastatic breast cancer subjects
  • Presence of at least one measurable lesion per RECIST v 1.1
  • Subjects must have HER2 positive breast cancer per ASCO-CAP guidelines, documented in a CLIA lab pathology report
  • Subjects must have had prior treatment with no more than 5 prior regimens of systemic treatment HER-2 targeting therapy or chemotherapy in the metastatic setting. One of these prior treatments must have been treatment with T-DXd.
  • Subjects with stable brain metastases
  • Acute toxicities from any prior therapy, surgery, or radiotherapy must have resolved to Grade ≤1 as per the NCI-CTCAE v 5.0, except alopecia, vitiligo, Grade 2 peripheral neuropathy, or endocrine toxicities that are stable on hormone replacement.
  • Adequate organ functions
  • Willing and able to understand and sign an informed consent inform and to comply with all aspects of the protocol

Key Exclusion Criteria:

Any subject who meets any of the following criteria is excluded from the study:

  • History of allergic reactions to any component of ARX788.
  • Prior history of interstitial lung disease, pneumonitis, or other clinically significant lung disease. Any requirement for supplemental oxygen.
  • Any active ocular infections or chronic corneal disorders
  • History of congestive heart failure, unstable angina pectoris, unstable atrial fibrillation, cardiac arrhythmia, or myocardial infarction within 6 months prior to enrollment
  • Grade 3 to 4 peripheral neuropathy (NCI CTCAE v 5.0).
  • History of unstable central nervous system (CNS) metastases
  • Radiotherapy outside of the brain administered < 7 days prior to first dose of ARX788
  • Current severe, uncontrolled systemic disease (eg, clinically significant cardiovascular, pulmonary, or metabolic diseases)
  • Any uncontrollable intercurrent illness, infection (including subjects with active, symptomatic Covid-19 infections), or other conditions that could limit study compliance or interfere with assessments
  • Exposure to any other investigational or commercial anticancer agents or therapies administered with the intention to treat malignancy within 14 days before the first dose of ARX788

This study investigates an investigational medication for patients with HER2-positive metastatic breast cancer. The purpose of this study is to evaluate the effects of this investigational medication in patients who have previously been treated with a specific therapy called T-DXd.

Participants in this study will receive the investigational medication through an intravenous infusion every three weeks. The study will monitor the participants' response to the treatment and any side effects they may experience. The investigational medication aims to target the HER2 receptors in breast cancer cells.

  • Who can participate: Participants must be 18 years or older with HER2-positive metastatic breast cancer and a life expectancy of at least 6 months. They should have been treated with up to five prior therapies, including T-DXd.
  • Study details: Participants will receive the investigational medication via intravenous infusion every three weeks. Those with a history of certain medical conditions or reactions to the investigational medication are excluded.
Updated on 09 Mar 2026. Study ID: 23-1590
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Study is selecting its participants from a population, or group of people, decided on by the researchers in advance.

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