Molecular Mechanisms of Clinical Resistance to Targeted Therapy Among Patients With Breast Cancer

January 26, 2026 updated by: Memorial Sloan Kettering Cancer Center
The purpose of this study is to learn why certain drugs stop working in patients.In lab studies, tumors become resistant in several ways. Specific molecules seem to change and this may be why therapy stops working. However, we do not know if the same molecules change in patients. This study is being done to see if they do change. If we learn more about how patients become resistant, we may be able to offer better treatment in the future.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Actual)

269

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New Jersey
      • Basking Ridge, New Jersey, United States, 07920
        • Memorial Sloan Kettering Basking Ridge (Consent Only)
      • Middletown, New Jersey, United States, 07748
        • Memorial Sloan Kettering Monmouth (Consent Only)
      • Montvale, New Jersey, United States, 07645
        • Memorial Sloan Kettering Bergen (Consent Only)
    • New York
      • Commack, New York, United States, 11725
        • Memorial Sloan Kettering Commack (Consent Only)
      • Harrison, New York, United States
        • Memorial Sloan Kettering Westchester (Consent Only)
      • New York, New York, United States, 10065
        • Memorial Sloan Kettering Cancer Center
      • Uniondale, New York, United States, 11553
        • Memorial Sloan Kettering Nassau (Consent Only)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Potential research subjects will be identified by a member of the patient's treatment team, the protocol investigator, or research team at Memorial Sloan-Kettering Cancer Center (MSKCC).

Description

Inclusion Criteria:

All patients:

  • Diagnosed with breast cancer.
  • Patient must be able to consent to a biopsy
  • Patient must be able to safely undergo a secondary biopsy, if needed.

Cohort 1

  • Patients who previously received treatment with anti-HER2 therapy (including trastuzumab, pertuzumab, TDM1, lapatinib, neratibin, or DS8201) as part of adjuvant chemotherapy and now have progressive or recurrent breast cancer or, patients who previously (or currently) received anti-HER2 therapy as part of a regimen for metastatic breast cancer and subsequently experienced.
  • Evidence of disease progression or recurrence after prior therapy (e.g. radiologic progression by RECIST criteria or new metastasis).
  • Prior tumor biopsy (may be original) defined as HER2+ by amplification by FISH (>1.9 gene copy number) or IHC 3+.

Cohort 2

  • Patients who previously received treatment with hormonal therapy (including aromatase inhibitors or SERMs or SERDs) as a part of adjuvant therapy and now have progressive or recurrent breast cancer or patients who previously (or currently) receive hormonal therapy as part of a regimen for metastatic breast cancer and subsequently experienced evidence of disease progression.

Cohort 3

  • Patients not eligible for Cohorts 1 or 2.

Exclusion Criteria:

  • Patients who are unable to consent to a biopsy.
  • Patients for whom a repeat biopsy would be medically unsafe

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Only
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
To look for mutations in druggable oncogenic pathways in tumors progressing on anti-HER2 therapy or hormonal therapy
Time Frame: 3 years
3 years
To characterize the activity of the PI3K signaling pathway in progressive breast tumors using proteomic methods
Time Frame: 3 years
3 years
To develop new laboratory models of treatment refractory breast cancer from human tumor specimens
Time Frame: 3 years
3 years

Secondary Outcome Measures

Outcome Measure
Time Frame
To look for mutations in druggable oncogenic pathways in tumor progressing on breast cancer targeted therapies
Time Frame: 3 years
3 years
To evaluate dynamic proteomic changes in response to inhibition of the RTK/PI3K/ATK/mTOR pathway.
Time Frame: 3 years
3 years
To characterize the genetic heterogeneity of progressive, metastatic tumors using next generation sequencing
Time Frame: 3 years
3 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Memorial Sloan Kettering Cancer Center

Collaborators

National Cancer Institute (NCI)

Investigators

  • Study Chair: Sarat Chandarlapaty, MD, PhD, Memorial Sloan Kettering Cancer Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 9, 2007

Primary Completion (Actual)

January 23, 2026

Study Completion (Actual)

January 23, 2026

Study Registration Dates

First Submitted

May 9, 2009

First Submitted That Met QC Criteria

May 9, 2009

First Posted (Estimated)

May 12, 2009

Study Record Updates

Last Update Posted (Actual)

January 28, 2026

Last Update Submitted That Met QC Criteria

January 26, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 06-163
  • MSKCC-06163

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Breast Cancer

Clinical Trials on immunoenzyme technique

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Dominican Republic

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe