A Study of Tucatinib vs. Placebo in Combination With Ado-trastuzumab Emtansine (T-DM1) for Patients With Advanced or Metastatic HER2+ Breast Cancer
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Phase
Phase 3
Status
Active, not recruiting
Study type
Interventional
Design
Randomized · Quadruple · Treatment
Enrollment
466actual
Sites
490
Countries
Australia, Austria, Belgium +17
Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →
Source: ClinicalTrials.gov, retrieved 2026-08-19
Dates
each axis at the precision it was filed, with the registry's own basis| Date | Filed | Basis | What it is |
|---|---|---|---|
| Start | 2019-10-02 | actual | When the study began enrolling |
| Primary completion | 2023-06-29 | actual | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2029-03-10 | estimated | The whole study's end, after follow-up |
| First posted | 2019-06-05 | actual | When this record first appeared on the registry |
| Results posted | 2024-07-30 | actual | When the sponsor posted results to the registry |
| Record updated | 2026-07-23 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Condition
- HER2-positive Breast Cancer
Interventions
- Drug: tucatinib — also filed as ONT-380
- Drug: placebo
- Drug: T-DM1 — also filed as Kadcyla
Primary outcome
what the primary-completion date above is the date OFProgression-Free Survival (PFS) as Per Response Evaluation Criteria in Solid Tumors (RECIST) Version (v)1.1 Based on Investigator Assessment
measured From the date of randomization to the date of PD or death from any cause or censoring date, whichever occurred first (maximum up to 43 months)
Posted documents
hosted by the registry — we link, never re-serveStudy Protocolposted 2023-11-08 · 2.1 MB · Prot_000.pdf
Statistical Analysis Planposted 2023-07-31 · 908 KB · SAP_001.pdf
Publications
- PMID 41260264 — linked by the registry
Linked on the registry record. A “linked by the registry” entry is NLM's own automated PubMed match, not a claim by the sponsor that the paper reports this study.
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