ARX788 in HER2-positive, Metastatic Breast Cancer Subjects (ACE-Breast-03)

NCT04829604 | Active Not Recruiting Phase 2 DMC FDA Drug

• 1 other identifier: ACE-Breast-03
• Study Type: interventional
• Target: 72
• Locations: 3 countries
• Sites: 33

Brief Summary

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

Conditions

HER2 Positive Metastatic Breast Cancer

Keywords

HER2-postive; Breast cancer; Antibody drug; Metastatic; ARX788; HER2

Outcome Measures

Primary Outcomes (1)

• Objective response rate (ORR)

  To evaluate the confirmed objective response rate (ORR) as determined by Investigator assessment based on Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) following treatment with ARX788. The ORR is defined as the number of subjects with a BOR of CR or PR divided by the number of response evaluable subjects.

  2 years

Secondary Outcomes (10)

• Duration of response (DOR)

  2 years

• Best overall response (BOR)

  2 years

• Disease control rate (DCR)

  2 years

• Overall survival (OS)

  2.5 years

• Progression-free survival (PFS)

  2 years

Other Outcomes (1)

• Evaluate Biomarker

  2 years

Study Arms (1)

ARX788

EXPERIMENTAL

The investigational medicinal product (IMP), ARX788, will be administered every 3 weeks (Q3W) by intravenous (IV) infusion.

Drug: ARX788

Interventions

ARX788 DRUG

The active pharmaceutical ingredient in ARX788 is an antibody drug conjugate (ADC) consisting of a humanized anti-HER2 monoclonal antibody (mAb) (IgG1κ) covalently conjugated to two microtubule-disrupting payloads AS269

Also known as: antibody drug conjugate (ADC)

ARX788

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Ambrx, Inc.: lead

Study Sites (33)

Research Site

Los Angeles, California, 90033, United States

Location

Research Site

Newport Beach, California, 92663, United States

Location

Research Site

San Francisco, California, 94158, United States

Location

Research Site

Whittier, California, 90602, United States

Location

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Atlanta, Georgia, 30322, United States

Location

Research Site

Chicago, Illinois, 60611, United States

Location

Research Site

Louisville, Kentucky, 40207, United States

Location

Research Site

Silver Spring, Maryland, 20904, United States

Location

Research Site

Boston, Massachusetts, 02215, United States

Location

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St Louis, Missouri, 63110, United States

Location

Research Site

Omaha, Nebraska, 68130, United States

Location

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Las Vegas, Nevada, 89128, United States

Location

Research Site

Camden, New Jersey, 08103, United States

Location

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New Hyde Park, New York, 11042, United States

Location

Research Site

New York, New York, 10028, United States

Location

Research Site

Shirley, New York, 11967, United States

Location

Research Site

The Bronx, New York, 10469, United States

Location

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Portland, Oregon, 97213, United States

Location

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Tigard, Oregon, 97223, United States

Location

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Philadelphia, Pennsylvania, 19104, United States

Location

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Dallas, Texas, 75246, United States

Location

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Houston, Texas, 77030, United States

Location

Research Site

San Antonio, Texas, 78229, United States

Location

Research Site

Norfolk, Virginia, 23502, United States

Location

Research Site

Tacoma, Washington, 98405, United States

Location

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Frankston, Victoria, 3199, Australia

Location

Research Site

Geelong, Victoria, 3220, Australia

Location

Research Site

Nedlands, Western Australia, 6009, Australia

Location

Research Site

Daegu, 42601, South Korea

Location

Research Site

Seongnam-si, 13620, South Korea

Location

Research Site

Seoul, 02841, South Korea

Location

Research Site

Seoul, 03722, South Korea

Location

Research Site

Seoul, 05505, South Korea

Location

MeSH Terms

Conditions

Breast Neoplasms; Neoplasm Metastasis

Interventions

ARX788; Immunoconjugates

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases; Neoplastic Processes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Antibodies; Immunoglobulins; Serum Globulins; Blood Proteins; Proteins; Amino Acids, Peptides, and Proteins; Globulins; Immunologic Factors; Physiological Effects of Drugs; Pharmacologic Actions; Chemical Actions and Uses

Study Officials

• Ambrx

  Ambrx, Inc.

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: One single arm, open label with intravenous infusion of ARX788 to assess the anticancer activity and safety of ARX788 in subjects with unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-positive (HER2+) breast cancer.

Study Record Dates

• First Submitted: March 18, 2021
• First Posted: April 2, 2021
• Study Start: October 26, 2021
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): June 1, 2027
• Last Updated: March 9, 2026

Record last verified: 2026-03

Locations

US (25); KR (5); AU (3)