# ACE-Breast-02

Source: https://onco.cc/trials/ace-breast-02/  
OnCo record `ace-breast-02` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A site-specifically conjugated HER2 ADC beat lapatinib-capecitabine on progression-free survival in China.

## Summary

ACE-Breast-02, a Chinese phase 3 sponsored by Zhejiang Medicine and Ambrx and reported in 2024 (it is registered in China rather than on ClinicalTrials.gov; NCT04829604 is the separate US study ACE-Breast-03), showed that ARX788, a HER2 antibody-drug conjugate made with site-specific conjugation, beat lapatinib plus capecitabine on progression-free survival in HER2-positive advanced breast cancer after trastuzumab and a taxane in China. It randomised 441 patients and met its primary endpoint with a clear reduction in the risk of progression; ARX788 uses non-natural amino acid conjugation from Ambrx, now part of Johnson & Johnson, with an MMAF-like payload, and ocular and pulmonary toxicity were noted. OnCo links it to site-specific conjugation and linker chemistry, ARX788 and lapatinib; a marketing application is planned in China with FDA Fast Track status. It is a single phase 3 against an older comparator, so how ARX788 compares with trastuzumab deruxtecan is the open question.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-07
- Phase: 3
- Setting: HER2+ advanced breast cancer after trastuzumab and taxane (China): ARX788 vs lapatinib + capecitabine
- Sponsor: Zhejiang Medicine / Ambrx
- Enrolled: 441
- Result: PFS 11.3 vs 8.2 months, HR 0.64.
- Outcomes: Progression-free survival: ARX788 11.3 months vs Lapatinib + capecitabine 8.2 months, HR 0.64
- Replication: Single phase 3; ACE-Breast-06 (brain metastases, phase 2) supportive.

## Sources

- ACE-Breast-02 primary publication (PubMed): https://pubmed.ncbi.nlm.nih.gov/39956849/

## Connected records

- cancers: [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/)
- technologies: [Site-specific conjugation & linker chemistry](https://onco.cc/technologies/site-specific-conjugation/)
- drugs: [ARX788](https://onco.cc/drugs/arx788/), [Lapatinib](https://onco.cc/drugs/lapatinib/)
- companies: [Ambrx](https://onco.cc/companies/ambrx/)

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