Therapeutic focus - What is plan B if A-beta Alzheimer's hypothesis is void?

The failure of Eli Lilly’s gamma secretase inhibitor, semagacestat, which targets the main amyloid-beta (A-beta) hypothesis of Alzheimer's disease (AD), raises once more the worrying possibility that targeting A-beta plaques may not be the breakthrough pathway to developing the first disease-modifying drug (Will gamma secretase Alzheimer's class survive the fall of semagacestat?, August 18, 2010).

Worrying because the bulk of current research dollars is being spent on agents that target A-beta – a review of pipeline data from EvaluatePharma shows that of the 139 clinical stage candidates in development for Alzheimer's, 30% are adopting the A-beta approach (see tables below). As such, although the most money is being spent on A-beta candidates, there remains a decent portion of products adopting slightly different pathways which could offer hope should the main hypothesis be proved wrong.