Antibody–Drug Conjugate in Refractory Metastatic Triple-Negative Breast Cancer

MedicalResearch.com Interview with:

Aditya Bardia, MBBS, MPH Director, Precision Medicine, Center for Breast Cancer, Attending Physician, Massachusetts General Hospital Cancer Center Harvard Medical School, Boston, MA 02114

Dr. Bardia

Aditya Bardia, MBBS, MPH
Director, Precision Medicine, Center for Breast Cancer,
Attending Physician
Massachusetts General Hospital Cancer Center
Harvard Medical School
Boston, MA 02114

MedicalResearch.com: What is the background for this study?

Response: Metastatic triple negative breast cancer is associated with aggressive tumor biology, and tends to affect younger patients and African Amerians. The response rate with standard chemotherapy regimens in patients with pre-treated metastatic TNBC ranges from 10-15%, and median progression-free survival ranges from 3-4 months. The median survival of metastatic TNBC is around 12 months and has not changed in the past 20 years. Thus, treatment of metastatic triple negative breast cancer represents an unmet clinical need.  

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Predictors of Chemosensitivity in Triple Negative Breast Cancer

MedicalResearch.com Interview with:

Christos Hatzis, PhD Assistant Professor of Medicine Director of Bioinformatics, Breast Medical Oncology Yale Comprehensive Cancer Center Yale School of Medicine New Haven, CT

Dr. Christos Hatzis,

Christos Hatzis, PhD
Assistant Professor of Medicine
Director of Bioinformatics, Breast Medical Oncology
Yale Comprehensive Cancer Center
Yale School of Medicine
New Haven, CT

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Triple negative breast cancer (TNBC) is a highly heterogeneous and aggressive disease, and although no effective targeted therapies are available to date, about one-third of patients with TNBC achieve pathologic complete response (pCR) from standard-of-care anthracycline/taxane (ACT) chemotherapy. The heterogeneity of these tumors, however, has hindered the discovery of effective biomarkers to identify such patients.

Identifying chemosensitive triple negative breast cancers could significantly impact
the survival of patients with these difficult to treat cancers until novel targeted
therapies become available. We hypothesized that genomic somatic aberrations may
provide important molecular clues about chemosensitivity in TNBC. Our study used
a carefully selected cohort of 29 uniformly treated TNBC patients who either achieved
pathologic complete response (pCR) or had extensive residual disease after neoadjuvant
anthracycline/taxane chemotherapy.

MedicalResearch.com: What are the main findings?

Response: We sequenced the coding genomic DNA of TNBC tumors and compared the somatic mutations found in the two groups at the two extremes of the chemosensitivity spectrum.

Our analysis revealed that, although mutations in single genes were not individually predictive, TNBC tumors bearing mutations in genes involved in the androgen receptor
(AR) and FOXA1 pathways were much more sensitive to chemotherapy.
We also found that mutations that lowered the levels of functional BRCA1 or BRCA2 RNA
were associated with significantly better survival outcomes; we derived a BRCA
deficiency signature to define this new, highly chemosensitive subtype of TNBC.
BRCA-deficient TNBC tumors have a higher rate of clonal mutation burden, defined as
more clonal tumors with a higher number of mutations per clone, and are also associated
with a higher level of immune activation, which may explain their greater chemosensitivity.

MedicalResearch.com: What should readers take away from your report?

Response: Mutations in the AR/FOXA1 pathway provide a novel marker for identifying chemosensitive TNBC patients who may benefit from current standard-of-care chemotherapy regimens.

The newly defined RNA-based BRCA-deficient subtype includes up to 50% of the
Triple negative breast cancer tumors that appear to be immune primed, and it would be of interest to investigate combinations of chemotherapy with immunotherapies, which could provide clinical benefit for these patients. Although our study showed concordant results in three different datasets, our key findings need to be further validated in a larger, prospectively designed study with archival samples.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: The comprehensive molecular analysis presented in this study directly links BRCA deficiency with increased clonal mutation burden and significantly enhanced chemosensitivity in Triple negative breast cancer and suggests that functional RNA-based BRCA deficiency needs to be further examined in TNBC. Our results suggest that the combination of immunotherapies with ACT chemotherapy or PARP inhibitors might be an effective strategy for treating BRCA-D tumors.

The strong connection of ACT chemosensitivity and immune activity with a new transcriptionally defined BRCA-D phenotype could help inform future therapeutic strategies for TNBC patients.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

Citation:

Predictors of Chemosensitivity in Triple Negative Breast Cancer: An Integrated Genomic AnalysisTingting Jiang,Weiwei Shi,Vikram B. Wali,Lőrinc S. Pongor,Charles Li,Rosanna Lau,Balázs Győrffy,Richard P. Lifton,William F. Symmans,Lajos Pusztai,Christos Hatzis

PLOS Medicine Published: December 13, 2016http://dx.doi.org/10.1371/journal.pmed.1002193

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Genetic Ancestry using Mitochondrial DNA in patients with Triple-Negative Breast Cancer

MedicalResearch.com Interview with:

Roshni Rao, M.D Breast Surgery University of Texas Southwestern

Dr. Roshni Rao

Roshni Rao, M.D
Breast Surgery
University of Texas Southwestern

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Triple negative breast cancer (TNBC) is characterized by not having estrogen, progesterone, or Her2Neu receptors. Although a less common type, it is aggressive, and leads to a disproportionate number of deaths from breast cancer.

TNBC is more common in young, African American women, but can be found in other ethnic groups as well.

This study performed mitochondrial DNA (mtDNA) analysis, to evaluate for patient genetic ancestry, in 92 patients with TNBC. In regards to self-identified ethnicity, there were 31 African-Americans, 31 Whites, and 30 Hispanics. Utilizing mtDNA, 13% of patients had discordance between self identified ethnicity and mtDNA analysis. Discordance was highest in the Hispanic group. The Hispanic patients were also much younger at initial age of diagnosis, and less likely to have a family history of breast cancer. Ancestry from Nigeria, Cameroon, or Sierre Leone were most common in the African-Americans with triple negative breast cancer.

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Genomic Instability Biomarker May Help Predict Treatment Response In Triple Negative Breast Cancer

MedicalResearch.com Interview with:
Melinda L. Telli, M.D. Assistant Professor of Medicine Stanford University Division of Medical Oncology Stanford, CA
Melinda L. Telli, M.D.
Assistant Professor of Medicine
Stanford University
Division of Medical Oncology

Stanford, CA 94305-5826

Medical Research: What is the background for this study? What are the main findings?

Response: A major goal of this study was to explore a DNA damaging chemotherapy regimen in patients with newly diagnosed early-stage triple-negative or BRCA1/2 mutation-associated breast cancer. This was based on the hypothesis that these types of tumors are more responsive to DNA damaging therapeutics. A second major goal was to identify predictors of response to this platinum-based therapy among patients with sporadic triple-negative breast cancer (TNBC).

Overall, this study demonstrated that the non-anthracycline and non-taxane neoadjuvant regimen of gemcitabine, carboplatin and iniparib resulted in a 36% pathologic complete response rate (pCR). This compares favorably to pCR rates commonly observed with anthracycline and taxane-based regimens in this group of patients. The response rate was higher among triple-negative breast cancer patients with a germline BRCA1 or BRCA2 mutation (56%).

Given the hypothesis of underlying DNA repair defects in sporadic triple-negative breast cancer, we also evaluated a novel measure of genomic instability to detect the accumulation of changes in the genomic landscape of a tumor attributable to defective homologous recombination DNA repair. Homologous recombination deficiency was assessed by loss of heterozygosity (HRD-LOH) in pretreatment core breast biopsies. Very importantly, we found that the HRD-LOH assay was able to identify patients with sporadic TNBC lacking a BRCA1 or BRCA2 mutation, but with an elevated HRD-LOH score, who achieved a favorable pathologic response. Continue reading