From Wikipedia,
the free encyclopedia
Assay sensitivity is a
property of a clinical trial
defined as the ability to
distinguish an effective treatment
from a less effective or
ineffective treatment. Assay
sensitivity is important in any
trial but has different
implications for trials intended
to show differences between
treatments (superiority trials)
and trials intended to show
non-inferiority. If a trial is
intended to demonstrate efficacy
by showing superiority of a test
treatment to control lacks assay
sensitivity, it will fail to show
that the test treatment is
superior and will fail to lead to
a conclusion of efficacy. In
contrast, if a trial is intended
to demonstrate efficacy by showing
a test treatment to be
non-inferior to an active control,
but lacks assay sensitivity, the
trial may find an ineffective
treatment to be non-inferior and
could lead to an erroneous
conclusion of efficacy.
A trial may have assay
sensitivity for an effect of 10
but not an effect of 5. (10 and 5
are effect sizes depending on what
you measure or check in trial).
You therefore need to know the
effect of the control drug. To
understand it better, the word
"assay" means a laboratory test to
find and measure the amount of a
specific substance. Borrowing the
analogy of a chemical assay,
clinical trials experts will not
accept the validity of a finding
of "difference" or "no difference"
between two treatments unless
another internal control confirms
"assay sensitivity," that the
study methods can show a
difference over the range of
interest if one is there.
When two treatments within a trial
are shown to have different
efficacy (i.e., when one treatment
is superior), that finding itself
demonstrates that the trial had
assay sensitivity. In contrast, a
successful non-inferiority trial
(i.e., one that has shown
non-inferiority), or an
unsuccessful superiority trial,
generally does not contain such
direct evidence of assay
sensitivity.
