OnCo
trialsTrialPositive

HORIZON-Breast01

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.

Interim analysis (ESMO 2025; Lancet Oncology 2026): PFS by BICR 30.6 vs 8.3 months (HR 0.22). Trastuzumab rezetecan is approved in China for HER2-mutant NSCLC (May 2025) with breast cancer filings following; it is the most advanced of several Chinese DXd-like ADCs.

Setting
HER2+ metastatic breast cancer after trastuzumab and taxane (China): trastuzumab rezetecan (SHR-A1811) vs pyrotinib + capecitabine
Phase
Phase 3
Sponsor
Jiangsu Hengrui
Registry
NCT05424835
Headline result
PFS 30.6 vs 8.3 months, HR 0.22.
Reported
2025
Enrolled
366
Replication
Comparable in magnitude to DESTINY-Breast03; no head-to-head with T-DXd.

Outcomes

1top
In plain words
What these results mean for people, not percentages
366 people took part
Progression-free survival (BICR)primarysurrogate endpoint
  • Median 30.6 vs 8.3 months with Trastuzumab rezetecan compared with Pyrotinib + capecitabine; about 22.3 months longer for half the group.
  • A median is a midpoint: half the people did better than this and half did worse, so it is not a prediction for any one person.
  • Put another way, the treated group had about 78 percent lower chance of the event at any given time (hazard ratio 0.22).
  • This is a surrogate endpoint: it measures the cancer being controlled or absent on scans and tests, which often, but not always, translates into living longer.
  • These results apply to the people the trial enrolled: HER2+ metastatic breast cancer after trastuzumab and taxane (China): trastuzumab rezetecan (SHR-A1811) vs pyrotinib + capecitabine. People in a different situation may not see the same effect.
  • The trial selected people by a biomarker (HER2); the result should not be assumed for people whose cancer does not have it.

Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.

366 participants enrolled.

Progression-free survival (BICR)primary
HR 0.22
Trastuzumab rezetecan
30.6 mo
Pyrotinib + capecitabine
8.3 mo
Source
EndpointArmnValueHR (95% CI)pSource
Progression-free survival (BICR)primaryTrastuzumab rezetecan—30.6 months0.22—link
Pyrotinib + capecitabine—8.3 months
Replication
Comparable in magnitude to DESTINY-Breast03; no head-to-head with T-DXd.

Connected

3top

Pages like this

not linked directly; found by shared links

cancers

1
HER2-positive breast cancer

drugs

2
Not filedSmall-molecule irreversible pan-HER kinase inhibitor
Pyrotinib · Airuini
Not mapped hereADC
Trastuzumab rezetecan