A groundbreaking initiative by an international consortium of scientists has identified three established pharmaceutical agents that hold considerable potential for either preventing or treating Alzheimer’s disease, thereby circumventing the arduous and costly process of developing entirely new compounds. This innovative research strategy focused on scrutinizing medications already in circulation for other ailments to ascertain their latent neuroprotective capabilities. The comprehensive investigation, spearheaded by the University of Exeter and generously supported by the Alzheimer’s Society, has yielded significant findings published in the esteemed journal Alzheimer’s Research and Therapy.
Among the diverse array of pharmaceuticals evaluated, a vaccine currently administered to prevent shingles emerged as the most compelling candidate for further investigation. Concurrently, sildenafil, widely recognized under the brand name Viagra for its use in treating erectile dysfunction, and riluzole, a drug prescribed for amyotrophic lateral sclerosis (ALS) or motor neurone disease, also demonstrated robust promise in preliminary assessments.
The strategic advantage of drug repurposing in the realm of neurodegenerative disorders, particularly dementia, cannot be overstated. In the United Kingdom, dementia stands as the foremost cause of mortality, impacting an estimated one million individuals, with projections indicating that one in three people alive today will confront this condition within their lifetime, a stark reality underscored by the absence of a definitive cure. The conventional pathway for pharmaceutical development, involving the creation of novel drugs, is a protracted endeavor, often spanning a decade to fifteen years and demanding investments in the billions of pounds, with no inherent guarantee of successful clinical outcomes. Consequently, the exploration of repurposing existing, approved, and extensively utilized medications presents a more expedited, secure, and economically viable route toward discovering effective interventions for Alzheimer’s. This vital research received additional backing from influential bodies such as the National Institute for Health and Care Research (NIHR), the Exeter Biomedical Research Centre, and the NIHR HealthTech Research Centre in Brain Health, underscoring the collaborative and multi-faceted nature of this scientific pursuit.
The meticulous selection process for identifying the most promising Alzheimer’s candidates involved a distinguished panel comprising twenty-one dementia specialists drawn from academic institutions, clinical settings, and the pharmaceutical sector, augmented by the invaluable perspectives of individuals directly affected by dementia. This expert group undertook a thorough review of eighty existing medications, with the primary objective of pinpointing those exhibiting the greatest therapeutic promise for managing or averting Alzheimer’s disease, which is responsible for over half of all diagnosed cases of dementia. Following a rigorous, multi-stage evaluation, the panel converged on three "priority candidates" deemed worthy of intensive follow-up research. The selection criteria for each of these drugs were multifaceted, encompassing their demonstrated ability to target biological mechanisms implicated in the pathogenesis of Alzheimer’s, the exhibition of encouraging preliminary results in both in vitro cell studies and in vivo animal models, and a well-established safety profile, particularly for use in geriatric populations.
The shingles vaccine, in particular, garnered significant attention due to its exceptionally strong preliminary indicators. This vaccine, typically administered in no more than two doses, boasts a long and well-documented history of safety and efficacy. Intriguingly, prior epidemiological studies have suggested a correlation between vaccination against shingles and a reduced incidence of dementia, with individuals receiving the vaccine exhibiting an approximate 16% lower likelihood of developing the condition. Researchers are now actively pursuing the establishment of a large-scale clinical trial within the United Kingdom dedicated to evaluating the shingles vaccine’s impact on individuals with Alzheimer’s or those at elevated risk of its onset. This proposed trial is envisioned to leverage the capabilities of PROTECT, an innovative online registry that facilitates participant engagement through annual health and lifestyle questionnaires and provides opportunities for involvement in brain health research initiatives.
Beyond the leading candidate, a cohort of five additional medications was identified as noteworthy but did not meet the stringent criteria to be classified as "priority candidates." These included fingolimod, a drug primarily used in the management of multiple sclerosis; vortioxetine, an antidepressant; microlithium, also employed in the treatment of depression; dasitinib, a targeted therapy for certain types of leukemia; and cytisine, a compound historically used in anesthetics. While these drugs did not advance to the highest tier of consideration, their inclusion in the initial review highlights the breadth of the scientific inquiry.
Leading experts in the field have emphasized the imperative for continued caution and the necessity of robust clinical trials to definitively ascertain the therapeutic value of these repurposed drugs. Dr. Anne Corbett, a Professor of Dementia Research at the University of Exeter, articulated the multifaceted approach required to combat dementia, stating, "Defeating dementia will necessitate exploring every avenue of research, from leveraging our existing knowledge base to discovering entirely new therapeutic agents for both treatment and prevention." She further elaborated on the significance of drug repurposing, deeming it "a critical component of this strategy, enabling us to transform current medicines for one condition into future treatments for another." Dr. Corbett underscored the importance of rigorous scientific validation, cautioning, "It is crucial to emphasize that these medications require further in-depth investigation before we can definitively determine their efficacy in treating or preventing Alzheimer’s. We now need to conduct comprehensive clinical trials to fully understand their true potential and confirm their effectiveness."
Echoing this sentiment, Professor Fiona Carragher, Chief Policy and Research Officer at the Alzheimer’s Society, conveyed a message of hope tempered with scientific pragmatism. "Dementia inflicts devastating consequences on lives, yet we remain steadfast in our belief that research will ultimately conquer this disease," she stated. Professor Carragher drew a parallel to historical pharmaceutical breakthroughs, remarking, "Years ago, we witnessed aspirin transition from its role as a pain reliever to its application in mitigating the risk of heart attack or stroke. This is precisely the kind of transformative impact we aspire to achieve within the field of dementia research, and it underscores why we consider drug repurposing to be one of the most dynamic and promising frontiers in our ongoing efforts." The collective endeavor signifies a paradigm shift in Alzheimer’s research, prioritizing accessible and efficient avenues for therapeutic discovery in the face of an escalating global health challenge.
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