First in Class Antibody-Drug Conjugate Shows Promise in Metastatic Breast Cancer Interview with:

Dr. Aditya Bardia  MD, MPH Assistant Professor, Medicine, Harvard Medical School Attending Physician, Medical Oncology Massachusetts General Hospital

Dr. Bardia

Dr. Aditya Bardia  MD, MPH
Assistant Professor, Medicine
Harvard Medical School
Attending Physician, Medical Oncology
Massachusetts General Hospital What is the background for this study? What are the main findings?

Response: Hormone receptor-positive (HR+)/ and human epidermal growth factor receptor 2-negative (HER2-) breast cancer is the most common sub-type of breast cancer. While metastatic HR+/HER2- breast cancer is initially treated with endocrine therapy-based combinations, including CDK 4/6 inhibitors, patients eventually have disease progression, but the response rate to standard chemotherapy is low (~10-15 percent, post-taxane setting). In particular, patients with visceral disease have a poor prognosis.

In this trial, we evaluated the efficacy of sacituzumab govitecan in patients with metastatic HR+/HER2- breast cancer, who had measurable disease and had received prior therapies for metastatic breast cancer. We observed an overall response rate of 31 percent in a heavily pre-treated population (prior number of therapies for metastatic breast cancer = 5; number of patients with prior CDK 4/6 inhibitor use = 69 percent). The responses were durable (median duration of response = 7.4 months). Neutropenia was the main adverse event noted (grade 3 neutropenia = 42 percent), and two patients (3.7 percent) discontinued the clinical trial due to adverse events. The response rate in patients with visceral metastaseswas 27 percent. What should readers take away from your report?

Response: Sacituzumab govitecan induced objective responses in a heavily pre-treated patient population with HR+/HER2- metastatic breast cancer, including those with visceral metastases and prior CDK 4/6 inhibitor exposure. The drug was well-tolerated and adverse events were manageable with supportive medications. What recommendations do you have for future research as a result of this study?

Response: The study results are very encouraging. Sacituzumab govitecan needs to be evaluated further in HR+/HER2- breast cancer, including rational combination therapy.

Disclosures: COI: I am a consultant and sit on the advisory board for Immunomedics. On a different topic, what can you tell us about the BLA recently filed with the FDA by Immunomedics to accelerate the approval status for sacituzumab govitecan’s as the only ADC for the treatment of metastatic triple negative breast cancer? 

Response: Currently, there are no FDA approved therapies specifically indicated for metastatic triple negative breast cancer (mTNBC). Patients with triple negative breast cancer (TNBC) tend to be younger, and have a higher predilection for visceral metastases. The response rate with standard chemotherapy is low, and clinically it represents an unmet need. However, the response rate observed with sacituzumab govitecan in patients with mTNBC (3rd line and plus setting) was quite impressive, and approximately double of what one would expect with standard therapy. Hence, there is tremendous excitement around this drug for patients with mTNBC, as they tend to have a poor prognosis.

Responses are from Aditya Bardia, MD, MPH. Dr. Bardia is the Director of Precision Medicine and an attending physician at Center for Breast Cancer, Massachusetts General Hospital, Harvard Medical School, Boston, MA. He is also the lead author of the abstract “Efficacy of sacituzumab govitecan (anti-Trop-2-SN-38 antibody-drug conjugate) for treatment-refractory hormone-receptor positive (HR+)/HER2-negative metastatic breast cancer” that was presented at the 2018 American Society of Clinical Oncology Annual Meeting.


ASCO 2018 abstract
Efficacy of sacituzumab govitecan (anti-Trop-2-SN-38 antibody-drug conjugate) for treatment-refractory hormone-receptor positive (HR+)/HER2- metastatic breast cancer (mBC). 
Aditya Bardia,et al June 3 2018

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Last Updated on June 6, 2018 by Marie Benz MD FAAD