Therapeutic Options in Alzheimer’s Disease: From Classic Acetylcholinesterase Inhibitors to Multi-Target Drugs with Pleiotropic Activity

Alzheimer's disease (AD) is a complex/multifactorial brain disorder involving hundreds of defective genes, epigenetic aberrations, cerebrovascular alterations, and environmental risk factors. The onset of the neurodegenerative process is triggered decades before the first symptoms appear, probably due to a combination of genomic and epigenetic phenomena. Therefore, the primary objective of any effective treatment is to intercept the disease process in its presymptomatic phases. Since the approval of acetylcholinesterase inhibitors (Tacrine, Donepezil, Rivastigmine, Galantamine) and Memantine, between 1993 and 2003, no new drug was approved by the FDA until the advent of immunotherapy with Aducanumab in 2021 and Lecanemab in 2023. Over the past decade, more than 10,000 new compounds with potential action on some pathogenic components of AD have been tested. The limitations of these anti-AD treatments have stimulated the search for multi-target (MT) drugs. In recent years, more than 1000 drugs with potential MT function have been studied in AD models. MT drugs aim to address the complex and multifactorial nature of the disease. This approach has the potential to offer more comprehensive benefits than single-target therapies, which may be limited in their effectiveness due to the intricate pathology of AD. A strategy still unexplored is the combination of epigenetic drugs with MT agents. Another option could be biotechnological products with pleiotropic action, among which nosustrophine-like compounds could represent an attractive, although not definitive, example.