ABSTRACT
To bring a drug to market regulatory agencies require demonstration of
benefit on a narrow range of outcomes and a lack of safety concerns. For asthma, the outcome of many randomized clinical trials has been a measure
of flow such as FEV1 or PEF, as well as symptoms and use of rescue med-
ications. More recently, measures of quality of life have been added to
broaden the scope of benefits examined. These randomized clinical trials
often do not have sufficient power or duration of follow-up to allow one
to compare the rates of clinically important outcomes such as severe
exacerbations requiring hospitalization, death, or long-term non-respira-
tory effects, for example, on growth or bone metabolism. Moreover, the selection criteria for clinical trials are quite strict. Subjects are usually
required to be non-smokers, to have little or no co-morbid disease, and
Samy Suissa is the recipient of a Distinguished Scientist award from the Canadian Institutes of Health Research.
