A unique ADC, which delivers a high dose of a cancer-killing drug to tumor cells through a targeted antibody, has been found in a global phase 3 clinical study to nearly double the survival time of patients with refractory metastatic triple-negative breast cancer. The study of the ADC drug sacituzumabgovitecan (SG), reported superior outcomes compared to single-agent chemotherapy, the standard for treating metastatic triple-negative breast cancer. The phase 3 results of the study, known as ASCENT, were published in the New England Journal of Medicine. SG, which was developed and is manufactured by Immunomedics, a subsidiary of Gilead Sciences, received accelerated approval by the U.S. Food and Drug Administration in April 2020 on the basis of favorable phase 1/2 clinical trials, with full approval contingent on the confirmatory phase 3 results. ASCENT is a global study to evaluate the safety and efficacy of the antibody drug conjugate compared to chemotherapy in 529 patients with metastatic triple-negative breast cancer whose cancer had relapsed or was resistant to at least two other forms of therapy. The investigators found that median progression-free survival with the ADC agent was 5.6 months compared to 1.7 months with chemotherapy, and that median overall survival was 12.1 months with the ADC agent compared to 6.7 months with chemotherapy. The study also found that the response rate – that is, shrinkage in the size of the metastatic tumor sites – was 35% after administration of ADC compared to 5% with chemotherapy.