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Extension Study of Lapatinib Plus Herceptin With or Without Endocrine Therapy

NCT00999804 · Status: ACTIVE_NOT_RECRUITING · Phase: PHASE2 · Type: INTERVENTIONAL · Enrollment: 128

Last updated 2025-03-12

Study results available
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Summary

Breast cancer is the most common malignancy in the U.S. Targeted therapies such as tamoxifen have been revolutionary in reducing tumor recurrences and mortality in early breast cancer. Using this successful paradigm, there has been a continued search for other targeted biologic therapies directed at receptors with known potential for promoting tumor growth.

The estrogen receptor (ER) and/or the HER signaling pathways are the dominant drivers of cell proliferation and survival in the majority of human breast cancers. Molecular targets of these pathways provide the most effective therapies in appropriately selected patients. However, de novo and acquired resistance remain major obstacles to successful treatment, and understanding the molecular pathways responsible for this resistance would enable the discovery of new strategies to overcome it.

The superiority of multi-drug HER2-targeted therapy over single agent therapy has been demonstrated in the preclinical setting using mouse xenografts. Trastuzumab, pertuzumab, lapatinib, and gefitinib, represent a group of therapeutic agents that target the HER family by different molecular mechanisms. Used as single agents in the MCF7/HER2-18 xenograft model, these drugs restored or enhanced sensitivity to tamoxifen. However, tumor growth inhibition lasted only 2-3 months before resistance to treatments occurred. However, when gefitinib, a HER1 inhibitor, was added to the two-antibody (T+P) regimen to block signals from HER1 dimers, a complete disappearance of nearly all xenograft tumors was observed; moreover, there was evidence of complete tumor eradication in 50% of the mice. The combination of lapatinib + trastuzumab was also highly effective in eradication of tumor burden, with no evidence of re-growth after 200 days. These xenograft models demonstrate that multi-drug HER2-targeted therapy more effectively induces apoptosis and inhibits proliferation, thereby resulting in tumor regression. Furthermore, HER2 combination therapy appears to more effectively reduce levels of phosphorylated pAKT and MAPK, thus resulting in sustained tumor inhibition.

Conditions

Interventions

DRUG

Lapatinib

1000 mg of Lapatinib by mouth daily

DRUG

Letrozole

Letrozole, 2.5 mg by mouth daily (for hormone receptor positive participants only)

DRUG

Trastuzumab

6 mg/kg intravenously, every 3 weeks

Sponsors & Collaborators

  • Translational Breast Cancer Research Consortium

    collaborator OTHER

  • GlaxoSmithKline

    collaborator INDUSTRY

  • Baylor Breast Care Center

    lead OTHER

Principal Investigators

  • Mothaffar Rimawi, MD · Baylor College of Medicine

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
FEMALE
Healthy Volunteers
No

Timeline & Regulatory

Start
2011-10-31
Primary Completion
2014-11-30
Completion
2026-01-31

Countries

  • United States

Study Locations

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Entities

Drugs
Diseases
Companies

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00999804 on ClinicalTrials.gov