Animal experiments and the doctor

Andre Menache's criticism (August 2002 JRSM¹) of Patrick Vallance's editorial² is itself flawed. A cornerstone of his argument is a study³ that ranks adverse drug reactions as the fourth leading cause of death in western hospitals. Menache concludes that since these drugs ‘were all thoroughly tested on laboratory animals’ such tests must be worthless.

In fact Lazarou et al.³ is a meta-analysis of the adverse effects of a group of drugs which must include many (e.g. digitalis glycosides, NSAIDs, steroids, antidiabetics, antitumour agents and anticoagulants)⁴ that were in use before the legislative requirements for animal experiments were introduced. Menache also overlooks the fact that the incidence of adverse effects has not changed over the past 30 years despite the introduction of new treatments for hypertension, peptic ulcer, arthritis and cancer and many other innovative medicines.

Anyway, preclinical animal studies are primarily designed to protect the phase I volunteers. During the subsequent phase II and phase III clinical investigations a candidate drug will generally be ‘tested’ on approximately 3000 humans (probably more than double the number of animals used for the preclinical work-up) before licensing.

We agree with Menache that individualized therapy is a desirable goal. The industry is moving in that direction, but it will be some time before the potential of pharmacogenomics is fully realized, and this will not, in itself, bring about a cessation of animal experiments. Virtually all veterinary drugs originate from human medicine, and for every species difference there are many more species similarities. So we will continue to rely upon animals to furnish us with information about mammalian biology and pathology and to protect our phase I subjects, as well as our patients, in the best tests that we can devise. It would be irresponsible not to.