A newer report of this study has been published: Trastuzumab deruxtecan versus trastuzumab emtansine in HER2-positive metastatic breast cancer: long-term survival analysis of the DESTINY-Breast03 trial (2024)
In HER2-positive metastatic breast cancer that has progressed after first treatment, the drug T-DXd (an antibody linked to a drug) kept the disease under control much longer than the earlier drug (T-DM1), and with long-term follow-up it also helped patients live longer. Its most important side effect is lung inflammation; tell your doctor straight away about any new cough or shortness of breath.
HER2-positive after prior anti-HER2 therapy; HER2-low (IHC 1+ or 2+ with negative ISH) after prior chemotherapy; HR-positive HER2-low or HER2-ultralow (IHC 0 with membrane staining) after one or more lines of hormone therapy
| Drug | Dose | Route | Schedule |
|---|---|---|---|
| Trastuzumab deruxtecan (T-DXd) | 5.4 mg/kg | IV | Day 1 |
On the page “Breast cancer” · Advanced HER2-positive and HER2-low disease
Metastatic HER2-positive or HER2-low breast cancer
| Drug | Dose | Route | Schedule |
|---|---|---|---|
| Trastuzumab deruxtecan | 5.4 mg/kg | IV (first dose over 90 minutes, then 30 minutes) | Day 1 |
Dose as in DESTINY-Breast03. Dose reduction: 4.4, then 3.2 mg/kg.
Dose source:.
On the page “Trastuzumab deruxtecan (T-DXd, Enhertu): dose and monitoring”
Doses follow the trial protocol, guideline or official drug label (source given in the notes of each regimen). Before prescribing, check blood counts, renal and hepatic function, drug interactions and the patient’s condition, and adjust the dose according to the drug label.
Trastuzumab deruxtecan 5.4 mg/kg IV every 3 weeks.
T-DM1 per the approved label (3.6 mg/kg IV every 3 weeks per the FDA label).
Source of the regimen details: ClinicalTrials.gov NCT03529110 (T-DXd 5.4 mg/kg every 3 weeks; T-DM1 per the approved label)
Doses are given for the information of specialists, as in this study’s protocol, and are not a prescription. Every drug must be prescribed by the treating physician for the individual patient.
Patients with HER2-positive metastatic or unresectable breast cancer previously treated with trastuzumab and a taxane.
Primary endpoint: progression-free survival by blinded independent central review. Secondary: overall survival, objective response and safety.
Drug-related grade 3 or 4 adverse events occurred in 45.1% of the T-DXd group and 39.8% of the T-DM1 group. Adjudicated drug-related interstitial lung disease/pneumonitis occurred in 10.5% of the T-DXd group and 1.9% of the T-DM1 group, none of grade 4 or 5.
DESTINY-Breast03 established T-DXd as the preferred second-line treatment for HER2-positive metastatic breast cancer (FDA approval May 2022). The NCCN guideline version 4.2026 reviews the long-term survival data (median overall survival 52.6 versus 42.7 months). Regular monitoring for interstitial lung disease is essential.
Open-label design; no crossover, which makes comparison with T-DXd given in later lines impossible; monitoring and management of ILD require experience.
This summary was prepared by the editorial team from the published paper; the original paper is the final reference. Read the original abstract on PubMed.
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