# HORIZON-Breast01

Source: https://onco.cc/trials/horizon-breast01/  
OnCo record `horizon-breast01` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A Chinese HER2 ADC cut the risk of progression by nearly 80% versus a pill-plus-chemotherapy standard, matching the scale of Enhertu's results.

## Summary

HORIZON-Breast01, trial NCT05424835 sponsored by Jiangsu Hengrui and reported at ESMO 2025 and in Lancet Oncology in 2026, showed that the Chinese HER2 antibody-drug conjugate trastuzumab rezetecan cut the risk of progression by nearly eighty percent compared with pyrotinib plus capecitabine in HER2-positive metastatic breast cancer after trastuzumab and a taxane, matching the scale of trastuzumab deruxtecan's results. It randomised 366 patients in China and met its primary progression-free survival endpoint by blinded review at an interim analysis with a very large effect. OnCo links it to trastuzumab rezetecan and pyrotinib. The effect is comparable in magnitude to DESTINY-Breast03, but there is no head-to-head comparison with trastuzumab deruxtecan, which is the open question.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-07
- Registry id: NCT05424835
- Phase: 3
- Setting: HER2+ metastatic breast cancer after trastuzumab and taxane (China): trastuzumab rezetecan (SHR-A1811) vs pyrotinib + capecitabine
- Sponsor: Jiangsu Hengrui
- Enrolled: 381
- Result: PFS 30.6 vs 8.3 months, HR 0.22.
- Outcomes: Progression-free survival (BICR): Trastuzumab rezetecan 30.6 months vs Pyrotinib + capecitabine 8.3 months, HR 0.22
- Replication: Comparable in magnitude to DESTINY-Breast03; no head-to-head with T-DXd.

## Sources

- ClinicalTrials.gov NCT05424835: https://clinicaltrials.gov/study/NCT05424835

## Connected records

- cancers: [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/), [Topoisomerase-I inhibitors (and ADC payloads)](https://onco.cc/technologies/topoisomerase-inhibitors/)
- drugs: [Pyrotinib](https://onco.cc/drugs/pyrotinib/), [Trastuzumab rezetecan](https://onco.cc/drugs/trastuzumab-rezetecan/)
- companies: [Jiangsu Hengrui Pharmaceuticals](https://onco.cc/companies/hengrui/)
- key papers: [Trastuzumab rezetecan versus pyrotinib plus capecitabine for patients with HER2-positive metastatic breast cancer (HORIZON-Breast01): interim analysis of a multicentre, open-label, randomised, controlled, phase 3 trial](https://onco.cc/key-papers/paper-horizon-breast01-lancet-oncol-2026/)

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