Clinical trial · Interventional
A Study of Trastuzumab Emtansine in Combination With Atezolizumab or Placebo as a Treatment for Participants With Human Epidermal Growth Factor 2 (HER2)-Positive and Programmed Death-ligand 1 (PD-L1)-Positive Locally Advanced (LABC) or Metastatic Breast Cancer (MBC)
A Randomized, Multicenter, Double-Blind, Placebo-Controlled Phase III Study of the Efficacy and Safety of Trastuzumab Emtansine in Combination With Atezolizumab or Placebo in Patients With HER2-Positive and PD-L1-Positive Locally Advanced or Metastatic Breast Cancer Who Have Received Prior Trastuzumab- (+/- Pertuzumab) and Taxane-Based Therapy (KATE3)
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Why stopped (as posted): Due to low enrollment, the Sponsor decided to prematurely terminate the study
Summary
Brief summary (as posted)
This study will evaluate the efficacy, safety and patient-reported outcomes of trastuzumab emtansine plus atezolizumab compared with trastuzumab emtansine plus placebo in participants with HER2-positive and PD-L1-positive LABC or MBC.Participants must have progressed either during or after prior trastuzumab- (+/- pertuzumab) and taxane-based therapy for LABC/MBC; or during (or within 6 months after completing) trastuzumab- (+/-pertuzumab) and taxane-based therapy in the neoadjuvant and/or adjuvant setting.
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Metastatic Breast Cancer | Malignant Breast Neoplasm | CURATED_BROADER | 0.78 |
Interventions
Interventions (3)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Atezolizumab | Drug | Atezolizumab | ALIAS |
| Placebo | Other | — | UNRESOLVED |
| Trastuzumab Emtansine | Drug | Trastuzumab Emtansine | ALIAS |
Design
Arms and outcomes
Arms (2)
- type
- ACTIVE_COMPARATOR
- label
- Arm A: Trastuzumab Emtansine and Placebo
- description
- Placebo matched to atezolizumab followed by trastuzumab emtansine 3.6 milligrams per kilogram (mg/kg) intravenous (IV) infusion on Day 1 Cycle 1 and thereafter on Day 1 of each 21-day cycle until disease progression, unmanageable toxicity, or study termination by the sponsor.
- interventionNames
- Drug: Trastuzumab Emtansine
- Other: Placebo
- type
- EXPERIMENTAL
- label
- Arm B: Trastuzumab Emtansine and Atezolizumab
- description
- Atezolizumab 1200 mg IV infusion followed by trastuzumab emtansine 3.6 mg/kg IV infusion on Day 1 Cycle 1 and thereafter on Day 1 of each 21-day cycle until disease progression, unmanageable toxicity, or study termination by the Sponsor.
- interventionNames
- Drug: Trastuzumab Emtansine
- Drug: Atezolizumab
Primary outcomes (2)
Eligibility
Eligibility (as posted)
- Sex
- All
- Minimum age
- 18 Years
Show eligibility criteria text
Inclusion Criteria: * HER2+ and PD-L1+ locally advanced (LABC) or metastatic breast cancer (MBC) * Progression must have occurred during most recent treatment for LABC/MBC or during, or within 6 months after completing, neoadjuvant and/or adjuvant therapy * Prior treatment with trastuzumab (+/- pertuzumab) and taxane in the neoadjuvant and/or adjuvant, locally advanced, or metastatic setting * No more than two prior lines of therapy in the metastatic setting * Measurable disease per RESIST version 1.1 * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 * Life expectancy \>= 6 months * Adequate hematologic and end-organ function * For women of childbearing potential: agreement to remain abstinent or use contraception, and agreement to refrain from donating eggs * For men: agreement to remain abstinent or use contraceptive measures, and agreement to refrain from donating sperm Exclusion Criteria: * Prior treatment with trastuzumab emtansine in metastatic setting * History of exposure to cumulative doses of anthracyclines * Symptomatic or actively progressing central nervous system (CNS) metastases; asymptomatic CNS lesions ≤ 2cm without clinical requirement for local intervention or asymptomatic patients with treated CNS lesions are eligible * Current Grade \>= 3 peripheral neuropathy * Cardiopulmonary dysfunction * History of malignancy within 5 years prior to initiation of study treatment, with the exception of the cancer under investigation and malignancies with a negligible risk of metastasis or death * History of leptomeningeal disease * Active or history of autoimmune disease or immune deficiency * Active hepatitis B, hepatitis C and/or tuberculosis * Prior allogeneic stem cell or solid organ transplantation * Receipt of a live, attenuated vaccine within 4 weeks prior to initiation of study treatment, during treatment, or within 5 months following the last dose of study treatment * Pregnancy or lactation
References
Publications (0)
Data not yet available