Amyloid-Based Therapeutics: Findings Translated into Novel Treatments
For decades following the 1906 identification of Alzheimer’s disease (AD), it was believed that the disorder was untreatable. Only in the late 1970s, with the introduction of the cholinergic hypothesis of the underlying mechanisms of AD, were treatment options considered possible. The first positive treatment study was conducted in 1985. In 1993, tacrine, a cholinesterase inhibitor, was approved for the treatment of AD; three similar drugs soon followed. Memantine, an NMDA receptor antagonist, was approved in 2003, representing a second therapeutic class for AD.Cholinesterase inhibitors were the first therapeutic options successfully employed, and there is strong evidence these agents confer benefits. The addition of memantine to the standard course of therapy can be beneficial as well, particularly at the moderate stages of the disorder (Mini-Mental State Exam score of ≤14). For patients without cardiovascular disease, diabetes, or statin use, 1,000 IU vitamin E BID is a consideration to mitigate the effects of AD. However, there is presently concern over the risks involved in vitamin E therapy. Unfortunately, there are no established treatments for mild cognitive impairment (MCI). Vitamin E is ineffective in treating MCI, and cholinesterase inhibitors, while possibly risky, are only minimally effective. The need for effective treatment remains expansive. The benefits of the available agents are modest, and there are currently no treatments for individuals with memory impairment who do not yet meet the diagnostic criteria for AD.