Biomedical Engineering Reference
In-Depth Information
continuous discovery that is not defi ned by phases but
rather by what we learn as we go.
21
Gottlieb acknowledges that:
. . . adaptive approaches are not a panacea to all of our
challenges, and enabling them is not a sure thing.
Adaptive procedures are more complicated to design
and to analyze, and in some settings are more diffi cult
to implement.
Moreover, he is well aware of:
. . . trepidation about the use of adaptive features and
reluctance to consider a variety of enrichment and
adaptive designs. In many cases, researchers are still
unaware of the option to use adaptive designs
because standard statistical courses and packages do
not include them.
22
There are political and ethical issues here as well. Steve
Zisson notes:
Purists will argue that changing a trial midway through
a study somehow benefi ts pharmaceutical companies
by potentially allowing them to manipulate results.
Some worry that bias is more likely when results
are known during the trial, compared with keeping
trials blind.
23
Concrete proposals are under consideration to mitigate such
worries.
24
Since FDA is interested in adaptive designs for the study of
investigational new drugs, it is unlikely they would object to
the use of adaptive designs in the formative evaluation of
