BACKGROUND: Patients with metastatic triple-negative breast cancer have a poor 
prognosis. Sacituzumab govitecan is an antibody-drug conjugate composed of an 
antibody targeting the human trophoblast cell-surface antigen 2 (Trop-2), which 
is expressed in the majority of breast cancers, coupled to SN-38 (topoisomerase 
I inhibitor) through a proprietary hydrolyzable linker.
METHODS: In this randomized, phase 3 trial, we evaluated sacituzumab govitecan 
as compared with single-agent chemotherapy of the physician's choice (eribulin, 
vinorelbine, capecitabine, or gemcitabine) in patients with relapsed or 
refractory metastatic triple-negative breast cancer. The primary end point was 
progression-free survival (as determined by blinded independent central review) 
among patients without brain metastases.
RESULTS: A total of 468 patients without brain metastases were randomly assigned 
to receive sacituzumab govitecan (235 patients) or chemotherapy (233 patients). 
The median age was 54 years; all the patients had previous use of taxanes. The 
median progression-free survival was 5.6 months (95% confidence interval [CI], 
4.3 to 6.3; 166 events) with sacituzumab govitecan and 1.7 months (95% CI, 1.5 
to 2.6; 150 events) with chemotherapy (hazard ratio for disease progression or 
death, 0.41; 95% CI, 0.32 to 0.52; P<0.001). The median overall survival was 
12.1 months (95% CI, 10.7 to 14.0) with sacituzumab govitecan and 6.7 months 
(95% CI, 5.8 to 7.7) with chemotherapy (hazard ratio for death, 0.48; 95% CI, 
0.38 to 0.59; P<0.001). The percentage of patients with an objective response 
was 35% with sacituzumab govitecan and 5% with chemotherapy. The incidences of 
key treatment-related adverse events of grade 3 or higher were neutropenia (51% 
with sacituzumab govitecan and 33% with chemotherapy), leukopenia (10% and 5%), 
diarrhea (10% and <1%), anemia (8% and 5%), and febrile neutropenia (6% and 2%). 
There were three deaths owing to adverse events in each group; no deaths were 
considered to be related to sacituzumab govitecan treatment.
CONCLUSIONS: Progression-free and overall survival were significantly longer 
with sacituzumab govitecan than with single-agent chemotherapy among patients 
with metastatic triple-negative breast cancer. Myelosuppression and diarrhea 
were more frequent with sacituzumab govitecan. (Funded by Immunomedics; ASCENT 
ClinicalTrials.gov number, NCT02574455; EudraCT number, 2017-003019-21.).