4
THE BULLETIN
FEATURE
Long used in clinical trials to determine the efficacy of new drugs,
placebos are earning their own place in medical studies.
By Barbara K. Gehrett, MD
SINCE THE END OF WORLD WAR II,
th
e standard for clinical research has
been a randomized controlled trial (RCT) in which a new drug is compared to a
placebo. As drug companies shepherd their products through the various phases
of study (see table on page 6), a curious phenomenon has been observed:
More and more compounds are failing due to lack of efficacy. In 2008, only
18 percent of Phase II trials were successful and only 50 percent of Phase III
B
trials were. oth of these figures represent a striking drop from 2001.
1
Why should so many promising drugs now fail, when historically many more
have been brought to market? Research has turned up a surprising factor
in this trend: the placebo effect. Since the 1980s, it appears
the placebo effect is getting more robust.
2
si
Increa ng placebo response rates have been noted in
al
clinical tri s of antipsychotic treatment for acute schizo
-
phrenia. Columbia University’s Bret R. Rutherford, et
al, compared trials in 1991 with trials in 2006. The
placebo effect—a patient’s tendency to feel the
desired effects of a drug even if he or she is not
given the actual drug—can skew test results. In
some of the later trials, the placebo response
t
t it
f
ai
was so great ha caused the drugs to l.
3
It’s not just new drugs that are failing. In
th
la
99
0s
al
f
di
e te 1 , a reev uation o az
-
epam showed it was no longer superior
i
it
ta
hi
to a placebo n the Un ed S tes, w le
