FDA approves targeted therapy for metastatic triple-negative breast cancer

The antibody-drug conjugate sacituzumab govitecan (Trodelvy) is now approved to treat people with metastatic, triple-negative breast cancer that has grown after past lines of treatment. The  Food and Drug Administration approved sacituzumab govitecan based on results from a phase I/II trial published in 2019.

Background

Triple-negative breast cancer responds well to chemotherapy, but there are few targeted therapies available because it does not have the same features as other types of breast cancer. When metastatic triple-negative breast cancer grows on one chemotherapy, the best option for most people is to replace it with another chemotherapy.

Sacituzumab govitecan is an antibody-drug conjugate. It links a chemotherapy medicine to a targeted antibody. The antibody helps the medicine more selectively target cancer cells, with the hope of better attacking cancer cells while doing less harm to healthy cells in your body.

The FDA approval was based on results of a phase I/II trial that tested sacituzumab govitecan in 108 people with metastatic triple-negative breast cancer that had grown on past lines of treatment. People in the study had at least two previous treatments, and the average number was three.

The main measure for the study was objective response rate, the percentage of people whose cancer shrank or disappeared while being treated with sacituzumab govitecan.Everyone in the trial received sacituzumab govitecan; there was no control group for comparison. Of all participants

• One-third had a response.
• The average length of response was 7.7 months.

Sacituzumab govitecan comes with warnings for low counts of certain blood cells and severe diarrhea. The study reported that 62 percent of participants reported diarrhea, and in 8 percent of participants it was severe enough to need medical care. Other side effects reported included nausea, vomiting, and fatigue.

The positive results and the lack of options for people with cancer growth after several lines of therapy led the FDA to pay special attention to this medicine. It was named a Breakthrough Therapy in 2016 and it went through Priority Review, meaning the FDA made a decision more quickly than usual.

What this means for you

While targeted therapies have proliferated for other types of breast cancer, chemotherapy still remains the rule for most people with metastatic triple-negative breast cancer. The approval of sacituzumab govitecan marks an important advance for a group of people who have limited choices about which type of chemotherapy to try next.

Sacituzumab govitecan provides a different option and hope for better outcomes. And because this medicine was studied in people with metastatic breast cancer that had grown, it is an option that has shown results even if you already had several lines of treatment.