17/10/05 13:06:15.38 8CwGr/wg.net
The historical trials assessed Ch ? P, the effect of the active control compared to placebo.
The NI trial assesses T ? Cn , the effect of the test drug compared to active control. If the outcome for the active control is constant across studies,
then Cn = Ch, and the sum T ? Cn + Ch ? P = T ? P represents the effect of the test drug compared to placebo.