The treatment of chronic infl ammatory diseases was revolutionized by the discovery
of the therapeutic utility of corticosteroids in the 1950s. Since this time they
have been the mainstay of treatment for chronic infl ammatory diseases. Their utility
has been tempered, however, by the increasing risk of debilitating side effects
with higher dose therapy. This is important because a reasonable proportion of
patients with severe asthma do not respond well to high doses of inhaled or even
oral corticosteroids. Thus 5% of asthmatics who do not respond to corticosteroid
therapy account for
50% of the total healthcare costs for asthma. In addition,
patients with chronic obstructive pulmonary disease also show little or no responsiveness
to conventional corticosteroid therapy.