Commentary on “A roadmap for the prevention of dementia: The inaugural Leon Thal Symposium.” Prevention of dementia: A few heretical proposals

Preventing dementia is a necessary, but difficult, challenge. The roadmap drawn up by the participants at the inaugural Leon Thal Symposium is helpful in that it discusses the many obstacles to achieving such a goal [1]. These obstacles all seem equally difficult to overcome, whether they relate to scientific knowledge itself, which is not yet fully established, or to practical issues. Despite this situation, we should not be content simply to reproduce the clinical trials currently used to obtain registration for Alzheimer’s disease medication. “Following in Leon Thal’s footsteps,” we should push ourselves to go further. In the absence of established facts, I suggest that we facilitate the development of preventive studies (such as Alzheimer’s Disease Anti-inflammatory Prevention Trial [ADAPT], Gingko in Evaluation of Memory [GEM], and GuidAge) by implementing a series of measures that are not perfect but do, in my opinion, present more advantages than drawbacks: First are measures designed to encourage the implementation of preventive trials by pharmaceutical laboratories, with the focus on nontoxic medication that is already available on the market and is therefore not very costly (without any help, no company would be interested in expensive trials for a cheap drug). The authorities could forbid generic versions of these medications from being marketed during the trial. With the same purpose in mind, extending the term of patents could also be an option. It might even be conceivable to grant a temporary registration (in this indication) for the length of the preventive study, provided that the results of the epidemiologic surveys are conclusive and that these surveys deal with an individual product (for example, Ginkgo biloba extract, EGb 761) rather than a therapeutic class (for example, nonsteroid anti-inflammatories). The example of anti-inflammatories and estrogens indicates that such a measure would be far from perfect because preventive trials were in fact unsuccessful (despite the epidemiologic evidence). However, this does not mean that we should reject it, given what is at stake. Second are measures to develop studies that pharmaceutical laboratories, by their very nature, are unable to conduct. The National Institutes of Health and other official agencies could set up preventive clinical trials, consisting of mixing a cocktail of low-toxicity products that could, for various reasons, be suitable as a preventive medication. One