Another word for control Arm is "placebo group".... adding placebo group costs more money...
Also, in case of the GOG trail, statistics were already know , so no need for placebo group...
Also, in case of phase 1-2 An*l cancer, it has 100% complete response... so why do you need a control arm (placebo)? 100% is as good as it gets...
Also, in case of H&N, 100% complete response (all 8 out of 8 patients cured of throat cancer)... so why waste money and time in placebo unless FDA required?