HengRui's SHR-A1811 cuts progression risk 78% versus pyrotinib in HER2+ breast cancer
Interim HORIZON-Breast01 data show median PFS of 30.6 months versus 8.3 months, but the trial remains open and final results are not yet in.
Executive Summary
- HORIZON-Breast01's interim analysis shows SHR-A1811 cut median progression-free survival risk to 30.6 months versus 8.3 months for pyrotinib plus capecitabine, a hazard ratio of 0.22 with p<0.0001 across 287 randomized patients. That is a large effect size in a randomized, BIRC-assessed phase 3 trial, not a small hypothesis-generating cohort.
- Grade 3 or higher neutropenia hit 54% of the SHR-A1811 arm versus 9% of control, alongside interstitial lung disease in 3% of treated patients. The efficacy signal comes with a tolerability cost that any regulatory or clinical adoption decision will need to weigh.
- The trial's primary completion date remains 2026-12-31 and overall survival data are immature at this cutoff. This is an interim read, not the final word on the drug's benefit-risk profile.
- HengRui runs 14 active SHR-A1811 trials spanning HER2-positive, HER2-low, and triple-negative breast cancer, including a head-to-head against trastuzumab emtansine in earlier lines. A positive interim signal here has readthrough to that broader program even though no other trial has reported comparable data yet.
The interim data
The randomized, open-label, controlled phase 3 trial enrolled 287 patients at 50 hospitals in China, assigning 142 to SHR-A1811 at 4.8mg/kg every three weeks and 145 to pyrotinib plus capecitabine, the current standard after trastuzumab and taxane failure Press ReleasePress ReleaseJul 1, 2026. At a June 30, 2025 data cutoff, median progression-free survival by blinded independent central review reached 30.6 months with SHR-A1811 versus 8.3 months with the control regimen, a hazard ratio of 0.22 with a 95% confidence interval of 0.15 to 0.34 and p<0.0001 Press ReleasePress ReleaseJul 1, 2026. The 12-month progression-free survival rate was 84.7% for SHR-A1811 versus 35.5% for control Press ReleasePress ReleaseJul 1, 2026. "Trastuzumab rezetecan improved progression-free survival versus pyrotinib plus capecitabine and showed a distinct safety profile in patients with HER2-positive breast cancer, presenting as a potential new treatment option," the investigators concluded Press ReleasePress ReleaseJul 1, 2026.
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
What it does not yet show
This is a prespecified interim analysis, not a final readout: 124 of 287 patients had experienced a progression-free at data cutoff, with median follow-up of 15.0 months in the SHR-A1811 arm versus 13.9 months in control Press ReleasePress ReleaseJul 1, 2026. The trial's registered primary completion date remains December 31, 2026, and overall survival, one of the trial's secondary endpoints tracked over roughly four years, was not reported in this disclosure Press ReleasePress ReleaseJul 1, 2026. The interim status means the effect size could narrow or the safety profile could shift as follow-up matures.
Safety signal
The tolerability profile diverges sharply from the comparator arm. Grade 3 or higher decreased neutrophil count occurred in 54% of SHR-A1811 patients versus 9% of control, decreased white blood cell count in 20% versus 3%, and decreased platelet count in 11% versus 1% Press ReleasePress ReleaseJul 1, 2026. Interstitial lung disease, a known class-associated risk for antibody-drug conjugates, occurred in 3% of SHR-A1811 patients Press ReleasePress ReleaseJul 1, 2026. Treatment-related serious adverse events were roughly comparable between arms, at 13% for SHR-A1811 versus 12% for control, and one death occurred in each arm, with the SHR-A1811 arm's death from septic shock deemed unrelated to treatment Press ReleasePress ReleaseJul 1, 2026.
Registry track record
The trial's operational history shows a 730-day cumulative delay to its primary completion date and a 41.6% increase in enrollment target, from 269 to 381 patients, both logged in a September 2024 registry update. AppliedXL's protocol-stability tool flags a high risk score of 95 out of 100 for the trial's operational signals even as the clinical result itself reads favorably, illustrating that execution risk and clinical outcome risk are separate axes here. HengRui has a 79% completion rate across its 298 tracked trials globally and runs 14 active or recruiting SHR-A1811 studies in breast cancer alone, including a head-to-head against trastuzumab emtansine in the neoadjuvant setting.
Competitive frame
No trial in the dossier's comparator set shares SHR-A1811's mechanism precisely; the named indication-landscape peers, trastuzumab deruxtecan, sacituzumab tirumotecan, and anbenitamab, target HER2, TROP2, and HER2 respectively through differing modalities, and none is flagged as a direct comparator. SHR-A1811's own target has not been classified in the dossier's mechanism tools, so no first-in-class or direct-precedent claim can be made. The closest same-drug precedent is HengRui's own earlier-line trial against trastuzumab emtansine, still recruiting toward a 2030 completion.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.