A Study of the Expression and Frequency of Tissue Biomarker Mutations in Breast Cancer that is Resistant or Refractory to Treatment with Trastuzumab and/or Pertuzumab


About this study

The purpose of this study is to measure the expression and frequency of the tumor tissue biomarkers (the genetics) of breast cancer, specifically the decreased presence and amount of a specific protein (Human epidermal growth factor receptor-2 [HER2]), how often genetic mutations occur, and why the cancer might or might not respond to monoclonal antibody therapy, such as trastuzumab emtansine (T-DM1) and/or pertuzumab.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Study closed to enrollment

Inclusion Criteria

  • Able to understand and willing to sign the informed consent form
  • Capable of providing written authorization for use and disclosure of protected health information per requirements of 45 Code of Federal Regulations (CFR) 164.508 (Health Insurance Portability and Accountability Act [HIPPA]), if applicable, before performance of any study-specific procedures or tests
  • ≥ 18 years old
  • Willing and able to undergo core biopsy or surgical resection/excision procedure on accessible tumor
  • Histologically confirmed diagnosis of HER2-positive metastatic breast cancer or cancer resistant to neoadjuvant therapy as determined by the Investigator as either
    • Presence of a tumor that demonstrated radiographic progression, with > 20% increase in longest diameter or newly emerged, during or within 2 months of stopping T-DM1 and/or pertuzumab-based therapy
    • Presence of a primary breast tumor that demonstrated < 50% regression in longest diameter during trastuzumab and pertuzumab-based neoadjuvant chemotherapy

Exclusion Criteria

  • Tumor biopsy or resection presents an unusual safety risk
  • Progressing tumor is in an anatomic location that is unreasonable to biopsy/excise, as determined by the Investigator
  • Risks associated with biopsy/resection will be greater than benefits received, as determined by the Investigator

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Jacksonville, Fla.

Mayo Clinic principal investigator

Alvaro Moreno Aspitia, M.D.

Closed for enrollment

Contact information:

Research Information Center


More information


Publications are currently not available

Mayo Clinic Footer