A Phase 3 interventional study of Trastuzumab deruxtecan (T-DXd) and Ribociclib with ET in Metastatic Breast Cancer, ER-positive Breast Cancer and Luminal B, sponsored by Danish Breast Cancer Cooperative Group. Withdrawn. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-12.
Sponsored by Danish Breast Cancer Cooperative Group · Phase 3, Interventional, and Treatment
The objective of this trial, DBCG R25, will be to evaluate the effect of trastuzumab-deruxtecan versus standard of care on progression-free survival (PFS) in first-line for patients with non-Luminal A, ER-positive/HER2-negative metastatic breast cancer
Study design and setting We will conduct an international, multicentre, open-label, randomised controlled trial. All oncological departments who treat patients with metastatic breast cancer can participate. The EU Clinical Trial Regulation will be applied.
Interventions Trial participants will be randomised to trastuzumab deruxtecan or standard treatment.
Trastuzumab deruxtecan
Patients randomised to trastuzumab deruxtecan will be treated as:
Trastuzumab deruxtecan until progression or intolerable toxicity, Trastuzumab deruxtecan: 5.4 mg/kg intravenous on day 1 of a 21 days cycle.
Standard
Patients randomised to standard will be treated as:
CDK4/6 inhibitor with an endocrine therapy until progression or intolerable toxicity CDK4/6 inhibitor: Physician's choice of ribociclib (600mg daily for 21 days in a 28 days cycle) or abemaciclib (150mg twice daily).
Endocrine therapy: letrozole (2.5mg daily), anastrozole (1mg daily), exemestane (25mg daily), tamoxifen (20mg daily) or fulvestrant (intramuscular 500mg every 4 weeks)
Other treatment Prophylactic antiemetics are allowed, including corticosteroids. Prophylactic antibiotics are allowed if deemed necessary for the patient. G-CSF is allowed when needed.
All other symptomatic treatment to perform best of care is allowed as long as name, administration and length is documented in the chart. Bone targeted agents are allowed. No other antineoplastic treatment is allowed.
Radiological evaluation Patients will initially be scanned every 9-12 weeks as per investigator's or co-investigator's discretion with minimum a CT of the thorax and abdomen or a FDG-PET/CT. Patients with response can have this interval extended. Upon progression treatment/control is to be done according to department preferences, but subsequent treatment and day of death must be registered.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HER2
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Trastuzumab deruxtecan until progression or intolerable toxicity: 5.4 mg/kg intravenous on day 1 of a 21 days cycle.
Drug: Trastuzumab deruxtecan (T-DXd)
\- CDK4/6 inhibitor with an endocrine therapy until progression og intolerable toxicity * CDK4/6 inhibitor: Physician's choice of ribociclib (600mg daily for 21 days in a 4 week schedule) or abemaciclib (125mg twice daily). * Endocrine therapy: letrozole (2.5mg daily), anastrozole (1mg daily), exemestane (25mg daily), tamoxifen (20mg daily) or fulvestrant (intramuscular 500mg every 4 weeks)
Drug: Ribociclib with ET · Drug: Abemaciclib with ET
Trastuzumab deruxtexan every three weeks
Also known as: Enhertu
Drug page: Ribociclib
Ribociclib with endocrine therapy
Drug page: Abemaciclib
Abemaciclib with endocrine therapy
This study also gives Fulvestrant, Anastrozole, Exemestane. No intervention listed here names it: that was found by reading the record.
Primary outcome
Progression-free survival (ITT)
Time frame: Up to 4 years after inclusion
Overall survival
Overall survival in ITT cohort
Time frame: Up to 4 years after inclusion
PFS by subtype
PFS by subtype (Luminal B, HER2-enriched and Basal-like)
Time frame: Up to 4 years after inclusion
OS by subtype
OS by subtype (Luminal B, HER2-enriched and Basal-like)
Time frame: Up to 4 years after inclusion
Quality of life
Quality of life EORTC QLQ-C30/BR23 during treatment and at progression.
Time frame: During treatment, estimated 18-24 months
Toxicity
Toxicity on treatment (NCI-CTC v. 5.0)
Time frame: During treatment, estimated 18-24 months
No study locations are listed for this record.
Plan to share: Undecided
No publications or documents are linked to this record.
Ran from Jan 2026 to primary completion in Jan 2026, 0 months.
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This study is withdrawn, as verified in Oct 2024. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Trastuzumab deruxtecan
Danish Breast Cancer Cooperative Group