IMMU – 132 Antibody-Drug Conjugate Improves Responses In Metastatic Triple-Negative Breast Cancer

Treatment with IMMU-132 (sacituzumab govitecan) elicited an overall response rate of 34 percent in patients with heavily pretreated metastatic triple-negative breast cancer (TNBC), according to updated findings from a clinical trial recently presented at the 2017 San Antonio Breast Cancer Symposium.1

About Triple-negative Breast Cancer

Approximately 12% of breast cancers are TNBC’s meaning that they are estrogen-receptor negative (ER-), progesterone-receptor negative (PR-), and human epidermal growth factor receptor 2-negative (HER2-). This means that TNBC is not stimulated to grow from exposure to the female hormones estrogen or progesterone, nor through an overactive HER2 pathway.

Unfortunately, many available and effective treatment options for the majority of breast cancers block the growth stimulating effects of ER, PR and/or HER2; therefore, TNBC has limited therapeutic options.  TNBC tends to be more aggressive and grow at a rapid rate.

There are no modifiable risk factors for TNBC. These cancers tend to occur more frequently in young premenopausal women, in African-American women, and in women who carry the abnormal inherited breast cancer susceptibility gene BRCA1. Novel treatment options for TNBC have lagged behind that of other types of breast cancers and are definitely needed.2

About IMMU – 132

Sacituzumab govetecan (IMMU-132) is an antibody drug that targets Trop-2, a calcium signal transducer that drives cancer cell growth in a majority of TNBC patients.  IMMU-132 delivers high doses of SN-38, the active metabolite of the chemotherapy drug Irinotecan that is 1000 times more active than Irinotecan itself.  IMMU-132 has received Breakthrough Therapy Designation from the U.S. Food and Drug Administration (FDA) for the treatment of patients with TNBC.3

The current study included 110 patients with TNBC that had failed two or more prior treatment regimens.  IMMU-132 was administered on days one and eight of each 28-day cycle. Study patients received a median of 14.5 doses of the medication and the median duration of treatment was 4.9 months.

In addition to producing an overall response rate of 34% another 11% of patients had stable disease (SD) for 6 months or more resulting in an overall disease control rate of 45% Average overall survival was 12.7 months.  The most common side effects were neutropenia, nausea, diarrhea, anemia, fatigue and vomiting.  Those receiving prior checkpoint inhibitors had an overall response rate of 47% and responses were similar between those receiving treatment as a third-line therapy or beyond.

These results compare favorably to traditional response rates with other single-agent chemotherapy medications used beyond the first-line setting, which rang from 6% to 15% percent across clinical trials.

Connect with other patients on CancerConnect to discuss these and other results and experiences with TNBC.


  1. Bardia et. al; GS1-07.  Sacituzumab govitecan (IMMU-132), an anti-Trop-2-SN-38 antibody-drug conjugate, as ≥3rd-line therapeutic option for patients with relapsed/refractory metastatic triple-negative breast cancer (mTNBC): Presented at: 20167San Antonio Breast Cancer.
  3. Bardia A, Diamond JR, Mayer IA, et al. Sacituzumab govitecan (IMMU-132), an anti-Trop-2-SN-38 antibody-drug conjugate (ADC) for the treatment of relapsed/refractory, metastatic triple-negative breast cancer (mTNBC): Updated results. Presented at: 2016 San Antonio Breast Cancer.

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