FLICKR, AUSTIN KIRKIt’s no secret that fewer than 10 percent of investigational drugs achieve regulatory approval and reach the marketplace. But the chances of success for drugs developed to treat Alzheimer’s disease are even more grim. Despite researchers’ valiant efforts to stall, slow, or even beat this devastating neurodegenerative condition, there are still no effective drugs available to the estimated 5.4 million Americans with the disease.
The scientific community has watched in dismay, time and again, as potential Alzheimer’s drugs that produced promising data in rodent models failed to work as expected in humans. For the most part, these drugs have pursued the promising “amyloid hypothesis,” which states that the disease may be caused by accumulation of beta-amyloid peptide in brain tissue resulting in neuron-killing plaques. But so far, no drug candidates targeting the beta-amyloid pathway have prevailed through late-stage clinical trials. Earlier this year, for example, Merck halted a Phase 2/3 trial of verubecestat, a small molecule inhibitor of a protein implicated in the buildup of beta-amyloid, called beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), due to a lack of efficacy. Another high-profile example occurred late last year, when ...
