Early Study Demonstrates Patritumab Deruxtecan Activity in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer

In the phase 2 study about half of the patients experienced significant tumor shrinkage, and nearly two-thirds saw some form of benefit from the treatment, including tumor shrinkage or stabilization

Charles H. Weaver, MD
1–2 minutes
Home » Breast Cancer » Early Study Demonstrates Patritumab Deruxtecan Activity in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer

Results from a recent multicenter, single-arm phase 2 study demonstrated that patritumab deruxtecan (HER3-DXd) shows promise for patients with advanced hormone receptor–positive, HER2-negative breast cancer who have progressed after multiple treatments. Here are the key findings from the ICARUS-BREAST01 study:

Efficacy

  • 53.5% of patients responded to the treatment
  • 90% of patients experienced tumor shrinkage
  • Median duration of response was 8.7 months
  • Median progression-free survival was 9.4 months

Safety

  • The treatment had a manageable safety profile
  • Most common side effects included fatigue, nausea, and diarrhea
  • 11.1% of patients discontinued treatment due to side effects

Patient Population

  • The study included patients whose cancer progressed after CDK4/6 inhibitor treatment and chemotherapy
  • Patients had received a median of 2 previous treatments for advanced breast cancer

Future Outlook

  • Results suggest patritumab deruxtecan could be a promising option for patients with limited treatment choices
  • Further larger trials are planned to confirm these findings

This new treatment option may offer hope for patients with advanced breast cancer who have exhausted other treatment options.

About Patritumab deruxtecan (HER3-DXd)

Patritumab deruxtecan is a type of medication known as an Antibody Drug Conjugate. It is comprised of 3 components: an anti-HER3 monoclonal antibody, patritumab, that is linked (connected) to a chemotherapy (topoisomerase I inhibitor0 payload, and an exatecan derivative, through a tetrapeptide-based cleavable linker. The ADC targets the HER3 receptor and delivers the chemotherapy payload to destroy the cancer cell.

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Patritumab Deruxtecan Shows Promise in HER3-Expressing Metastatic Breast Cancer

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Reference

Pistilli B, Pierotti L, Lacroix-Triki M, et al. Effiacy, safety, and biomarker analysis of ICARUS-BREAST01: A phase 2 study of patritumab deruxtecan (HER3-DXd) in patients with HR+/HER2– advanced breast cancer. Presented at: 42nd Annual Miami Breast Cancer Conference. March 6-9, 2025; Miami, Florida. Poster 82.

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