In many first in human (FIH) studies, participants are randomly allocated to active drug or placebo (PL) at each dose level, often in a 2:1 or 3:1 ratio. Results in PL participants for the different dose levels are combined to have an overall PL group. In Oncology studies, however, usually all patients receive active drug. Why, then, do most FIH studies have PL treated participants, while some FIH studies do not? Besides blinding (which is not unimportant) what specifically is gained from having PL patients in an FIH study? How does this help interpret the results – particularly of potential safety signals? Would it be possible to use the subject as their own control for all studies – especially for those studies involving patients, rather than healthy volunteers? This roundtable will discuss some hypothetical results to help see what value PL participants have for FIH studies.