for people ages 18 years and up (full criteria)
study start
estimated completion
Principal Investigator
by sara hurvitz (ucla)



This 2-part, Phase 1, open-label study will determine the recommended Phase 2 dose (RP2D) of ARX788 in subjects with advanced HER2 positive cancers and will assess the safety and anticancer activity in breast, gastric and other advanced HER2 positive solid tumors.

Official Title

A Phase 1, Multicenter, Open-label, Multiple Dose-escalation and Expansion Study of ARX788, as Monotherapy in Advanced Solid Tumors With HER2 Expression


Phase 1a will determine the recommended Phase 2 dose (RP2D) in subjects with advanced cancer whose HER2 test results are in situ hybridization (ISH) positive or immunohistochemistry (IHC) 3+, based on safety, tolerability, PK findings and antitumor activity. Phase 1b will assess the safety, tolerability, and PK and anticancer activity in five expansion cohorts, including breast cancer, gastric cancer / gastroesophageal adenocarcinoma, and other advanced HER2-positive solid tumors.


Breast Neoplasms, Gastric Neoplasm, Solid Tumors, HER2, antibody drug conjugate, breast cancer, gastric cancer, advanced solid tumors, HER2-overexpression, HER2-mutations, Neoplasms, Stomach Neoplasms, Immunoconjugates, ARX788


You can join if…

Open to people ages 18 years and up

  • Age >18 years
  • Life expectancy >3 months.
  • Female or male subjects whose advanced HER2 expressing cancer has failed standard of care treatments, or for whom such therapy is not acceptable to the subject. Subjects with advanced breast, gastric cancer, or other solid tumor who test positive for HER2 by ASCO/CAP criteria (either IHC or FISH) must have received prior treatment with a trastuzumab containing therapy. Subjects who have been previously treated with pertuzumab, TDM-1, lapatinib, or other available and accessible HER2-directed therapies or investigational therapies are eligible.
  • Disease measurability:
    • Phase 1a: measurable or non-measurable disease per RECIST v 1.1.
    • Phase 1b: measurable disease per RECIST v 1.1 (subjects with non-measurable disease are not eligible for Phase 1b).
  • Histopathologic evidence of cancer based upon pathology report.
  • Tumor tissue local laboratory HER2 testing results, adequate tumor sample available for confirmation of HER2 status. Subjects with other types of cancer must have previously tested locally for HER2 status by HER2 IHC or ISH assay.
  • Eastern Cooperative Oncology Group Performance Status of 0 to 1.
  • Acute toxicities from any prior therapy, surgery, or radiotherapy must have resolved to Grade 0 or 1 as per the NCI-CTCAE v 4.03 (phase 1a) and v 5.0 ( Phase 1b).
  • Adequate organ functions.
  • Willing and able to understand and sign an informed consent inform and to comply with all aspects of the protocol.
  • Female subjects must be surgically sterile, or have a monogamous partner who is surgically sterile, or at least 2 years postmenopausal, or who commits to use an acceptable form of birth control (defined as the use of an intrauterine device, a barrier method with spermicide, condoms, any form of hormonal contraceptives, or abstinence) for the duration of the study and for 3 months following the last dose of study treatment.
  • Male subjects must be sterile (biologically or surgically) or commit to the use of a reliable method of birth control (condoms with spermicide) for the duration of the study.

You CAN'T join if...

  • History of allergic reactions to any component of ARX788.
  • History of ocular events, or any current ongoing active ocular infections.
  • History of congestive heart failure, unstable angina pectoris, unstable atrial fibrillation, or cardiac arrhythmia within 12 months prior to enrollment
  • Grade 2 to 4 peripheral neuropathy (NCI CTCAE v 5.0)
  • History of unstable central nervous system (CNS) metastases
  • Current severe, uncontrolled systemic disease (eg, clinical 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.
  • Clinically significant surgical intervention (excluding diagnostic biopsy) within 21 days of the first dose of ARX788
  • Radiotherapy administered less than 21 days prior to the first dose of ARX788, or localized palliative radiotherapy administered less than 7 days prior to the first dose of ARX788, or radiotherapy-induced toxicity of Grade 2 or greater based on NCI-CTCAE v 5.0.
  • Pregnancy or breast feeding.
  • Known active HCV, HBV, and/or HIV infection.


  • UCLA Hematology-Oncology
    Santa Monica California 90095 United States
  • USC Norris Cancer Hospital
    Los Angeles California 90033 United States

Lead Scientist at University of California Health


in progress, not accepting new patients
Start Date
Completion Date
Ambrx, Inc.
Phase 1 research study
Study Type
About 106 people participating
Last Updated