Study of Trastuzumab Deruxtecan (T-DXd) vs Investigator's Choice Chemotherapy in HER2-low, Hormone Receptor Positive, Metastatic Breast Cancer

Official Title

A Phase 3, Randomized, Multi-centre, Open-label Study of Trastuzumab Deruxtecan (T-DXd) Versus Investigator's Choice Chemotherapy in HER2-Low, Hormone Receptor Positive Breast Cancer Patients Whose Disease Has Progressed on Endocrine Therapy in the Metastatic Setting (DESTINY-Breast06)


This study will evaluate the efficacy, safety and tolerability of trastuzumab deruxtecan compared with investigator's choice chemotherapy in human epidermal growth factor receptor (HER)2-low, hormone receptor (HR) positive breast cancer patients whose disease has progressed on endocrine therapy in the metastatic setting.

Trial Description

Primary Outcome:

  • Progression Free Survival (PFS) - in HR+, HER2-low populaton
Secondary Outcome:
  • Overall Survival (OS) - in HR+, HER2-low population
  • Progression Free Survival (PFS) - in intent to treat (ITT) population (HER2-Low and HER2 IHC >0<1+)
  • Overall Survival - in intent to treat (ITT) population (HER2-Low and HER2 IHC >0<1+)
  • Objective Response Rate (ORR) in HR+, HER-2 low populaton
  • Duration of response (DoR) - in HR+, HER-2 low populaton
  • Progression Free Survival by Investigator assessment - in the HR+, HER2-low population
  • Objective Response Rate (ORR) in the ITT population
  • Duration of response (DoR) - in the ITT population
  • PFS2 by Investigator assessment, time to first subsequent therapy (TFST) and time to second subsequent treatment or death (TSST) - in HR+, HER2-low and the ITT population
  • Safety and tolerability of drugs; number of adverse events (AEs)
  • Serum concentration of trastuzumab deruxtecan
  • Immunogenicity of trastuzumab deruxtecan
  • Health-related quality of life - EORTC-QLQ-C30
  • Time to deterioration in EORTC-QLQ-C30 scores
  • Health-related quality of life - EORTC QLQ-BR45
Eligible patients will be those patients who have had disease progression on at least 2 previous lines of endocrine therapies given for the treatment of metastatic disease or disease progression within 6 months of starting first line treatment for metastatic disease with an endocrine therapy combined with a CDK4/6 inhibitor. All patients must have historically confirmed HR positive (either estrogen receptor and/or progesterone receptor positive), HER2-low (defined as IHC2+/ISH- and IHC 1+) or HER2 IHC >0 <1+ expression, as determined by central laboratory testing results, advanced or metastatic breast cancer.

The study aims to evaluate the efficacy, safety and tolerability of trastuzumab deruxtecan compared with investigator's choice chemotherapy. This study aims to see if trastuzumab deruxtecan allows patients to live longer without the cancer getting worse, or simply to live longer, compared to patients receiving standard of care chemotherapy. This study is also looking to see how the treatment and the cancer affects patients' quality of life.

View this trial on

Interested in this trial?

Print this page and take it to your doctor to discuss your eligibilty and treatment options. Only your doctor can refer you to a clinical trial.


Canadian Cancer Society

These resources are provided in partnership with the Canadian Cancer Society