Drug allergies are a major problem in the clinic and during drug development. At the present
time, it is not possible to predict the potential of a new chemical entity to produce an allergic
reaction (hypersensitivity) in patients in preclinical development. Such adverse reactions,
because of their idiosyncratic nature, only become apparent once the drug has been
licenced. Our present chemical understanding of drug hypersensitivity is based on the
hapten hypothesis, in which covalent binding of the drug (metabolite) plays a central role in …