The ASCENT trial reports impressive results with a median overall survival (OS) 
increased from 6.7 months to 12.1 months with sacituzumab govitecan over 
single-agent chemotherapy, in metastatic triple negative breast cancer (TNBC) 
patients in second and subsequent line of therapy. We described design features 
in the ASCENT trial casting doubt on the extrapolation of the reported results 
to real world patients. First, the open-label design may exaggerate the effect 
of the experimental arm. Second, the choice of progression-free-survival (PFS) 
as a primary endpoint, debatable in metastatic TNBC, can lead to biases: early 
stopping rules may exaggerate efficacy results and informative censoring can 
bias PFS results interpretation. Third, the control arm was not a complete 
"physician's choice": it was restricted, preventing from using effective agents 
in this setting, and leading to a substandard control arm. Fourth and lastly, 
dose reduction and supportive care recommendations for the experimental drug 
were different between the trial protocol and the FDA labels, and favored the 
experimental arm as compared with the control arm. In conclusion, we described 
four design features in the ASCENT trial having the potential to favor the 
experimental arm or to penalize the control arm. It thus remains uncertain in 
which extent the reported outcomes will translate in the real world. Efforts 
should be made to avoid trial biases that will eventually prevent to conclude 
about their true impact in patients when applied broadly.