Sacituzumab govitecan improves survival in metastatic triple-negative breast cancer.

This study investigated the effectiveness and safety of sacituzumab govitecan (Trodelvy; SG) compared to chemotherapy in patients with relapsed or refractory metastatic triple-negative breast cancer (mTNBC). The data showed that SG significantly improved the survival outcomes of these patients compared to chemotherapy.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer (BC) that tests negative for female hormone receptors (estrogen and/or progesterone) and the HER2 protein. TNBC accounts for 10-15% of all BCs. It is associated with a poorer disease outcome compared to other subtypes of BC. Treatments for TNBC usually involve a combination of surgery, chemotherapy, and radiotherapy. However, treatment options are limited for those patients who relapse (cancer returns) or stop responding (refractory) to standard treatments.

SG is a biological treatment. Most BCs have on the surface of BC cells a protein called Trop-1. SG is made up of an antibody-drug that attaches to the Trop-2 protein on BC cells and a second drug that kills the cancer cells once it penetrates them. It may help patients who have not had success with other BC treatments and have developed metastatic cancer (cancer that has spread to other parts of the body). However, the effectiveness and safety of SG compared to chemotherapy in patients with relapsed or refractory (r/r) mTNBC have not been investigated.

This study involved 468 patients with r/r mTNBC. Patients were randomly assigned into 2 groups. Group 1 involved 235 patients who received SG. Group 2 involved 233 patients who received one of the following chemotherapy treatments: eribulin (Halaven), vinorelbine (Navelbine), capecitabine (Xeloda), or gemcitabine (Gemzar). The average follow-up period was 17.7 months.

The average survival without cancer progression was 5.6 months with SG and 1.7 months with chemotherapy. Patients who received SG were 59% less likely to have cancer progression than those who received chemotherapy.

The average overall survival was 12.1 months with SG and 6.7 months with chemotherapy. Patients who received SG were 52% more likely to have a better survival compared to those who received chemotherapy.

The objective response rate (complete or partial disappearance of cancer) was 35% for the SG group compared to 5% for the chemotherapy group.

Overall, a similar number of patients in both groups (99.6% with SG and 99.1% with chemotherapy) experienced side effects. The most common side effects were low white and red blood cell counts, diarrhea, nausea, fatigue, and hair loss.  

This study concluded that SG significantly improved the survival outcomes of patients with r/r mTNBC compared to chemotherapy.

This study was sponsored by Immunomedics, the manufacturers of SG. This study served as the basis for the approval of SG for patients with r/r mTNBC.