A breakthrough new target and a new drug in triple-negative breast cancer

Breast cancer, the most common cancer among women, accounts for %23 of newly diagnosed cancer cases. This rate is expected to rise in 2017 to %30. Despite this increase in the proportion of new breast cancer patients, no increase in disease-related mortality rates has been observed. This may be attributed to increased screening, improvements in surgical methods through modern new investigations, greater public awareness of early diagnosis, and newly developed medicines.

Triple-negative breast cancer, a breast cancer subtype, accounts for %15-20 of all breast cancers. Based on staining characteristics of the tumor tissue obtained, patients are classified as having triple-negative breast cancer if the estrogen receptor, progesterone receptor and HER2 receptor do not show staining. Chemotherapy is the most important treatment option when this disease has spread through the body. One newly developed drug is an antibody–drug conjugate called sacituzumab govitecan (IMMU-132), whose promising results were announced at the 2016 San Antonio Breast Cancer Symposium.

Cancer cells contain a protein called Trop-2 that activates a calcium-dependent signaling pathway. Activation of Trop2 causes growth signals to be sent into the cell. Sacituzumab govitecan (IMMU-132), considered a new targeted treatment for triple-negative breast cancer, is an agent consisting of an antibody–drug conjugate developed against this protein.

Study

In the study presented at the San Antonio Breast Cancer Symposium, time to disease progression was 6 months and overall survival was 16 months in patients who had previously received multiple chemotherapy treatments. Treatment benefits began within the first two months. Patients tolerated treatment easily; the most common side effect was a reduction in white blood cell count. No serious event related to this side effect occurred. Following this exciting study, the United States Food and Drug Administration (FDA) granted the drug breakthrough therapy status.

We will eagerly await results of studies now being initiated in other cancer types for this drug, which has demonstrated efficacy in triple-negative breast cancer patients who received multiple lines of treatment. We will continue following the drug’s approval processes and keeping you informed.