A comprehensive scientific endeavor has identified three established pharmaceutical agents, initially developed for distinct medical conditions, that exhibit significant potential for the prevention or treatment of Alzheimer’s disease. Rather than embarking on the lengthy and resource-intensive process of discovering entirely new therapeutic compounds, researchers have meticulously scrutinized medications already in widespread clinical use to ascertain their capacity to safeguard cognitive function. This innovative approach, known as drug repurposing, holds the promise of accelerating the availability of effective interventions for neurodegenerative disorders.
The investigation, generously supported by the Alzheimer’s Society and spearheaded by a team at the University of Exeter, culminated in findings published in the esteemed journal Alzheimer’s Research and Therapy. Among the pharmaceuticals under examination, a vaccine currently administered to prevent shingles demonstrated the most compelling therapeutic signals. Additionally, sildenafil, commonly recognized by its brand name Viagra and prescribed for erectile dysfunction, alongside riluzole, a drug utilized in the management of amyotrophic lateral sclerosis (ALS), also presented robust evidence of potential benefit in the context of Alzheimer’s disease.
The imperative for drug repurposing in the fight against dementia cannot be overstated, particularly within the United Kingdom where it stands as the leading cause of mortality. Affecting an estimated one million individuals, dementia represents a profound public health challenge, with projections indicating that one in three people born today will eventually develop the condition. Despite the widespread impact and the absence of a definitive cure, the development of novel pharmaceuticals from initial discovery to market approval typically spans a decade to fifteen years, incurring costs in the billions of pounds and carrying no inherent guarantee of success. Consequently, the strategic redeployment of existing, approved, and well-characterized medications offers a significantly more expeditious, cost-effective, and potentially safer pathway toward novel Alzheimer’s therapies. This pivotal research also benefited from the foundational support of the National Institute for Health and Care Research (NIHR), the Exeter Biomedical Research Centre, and the NIHR HealthTech Research Centre in Brain Health, underscoring a collaborative commitment to advancing neurological health.
The rigorous selection process for these prospective Alzheimer’s candidates involved an international consortium of twenty-one distinguished dementia specialists. These experts, drawn from academic institutions, clinical settings, and the pharmaceutical industry, collaborated with individuals directly impacted by dementia. Their collective mission was to meticulously evaluate eighty existing medications, identifying those that displayed the most auspicious prospects for either mitigating the progression or preventing the onset of Alzheimer’s disease, a condition responsible for over half of all diagnosed dementia cases.
Following a series of deliberative review cycles, the panel reached a consensus, designating three compounds as ‘priority candidates’ meriting further in-depth investigation. The selection criteria for each drug were multifaceted, encompassing its documented ability to interact with biological pathways implicated in the pathogenesis of Alzheimer’s, the exhibition of encouraging preliminary results in both in vitro cell cultures and in vivo animal models, and a well-established safety profile, particularly within the geriatric population.
The shingles vaccine, in particular, garnered significant attention and is now being advocated for rigorous clinical trials to definitively ascertain its efficacy in individuals diagnosed with Alzheimer’s or those at elevated risk of developing the disease. This vaccine, requiring no more than two doses and boasting a long history of safe administration, has been associated in prior epidemiological studies with a notable reduction in dementia incidence. Specifically, individuals who received the vaccine demonstrated an approximate 16% lower likelihood of developing dementia compared to unvaccinated cohorts. Researchers are actively working towards initiating a large-scale clinical trial in the UK to evaluate the shingles vaccine’s impact on dementia risk, leveraging the PROTECT online registry. This innovative platform allows volunteers to contribute annually via questionnaires detailing their health and lifestyle choices, while simultaneously participating in vital brain health research initiatives.
Beyond the top-tier candidates, a supplementary group of five medications was also identified as warranting further consideration, although they did not fully satisfy the stringent criteria for ‘priority candidate’ status. These included fingolimod, a treatment for multiple sclerosis; vortioxetine, an antidepressant; microlithium, also used for depression; dasitinib, a leukemia medication; and cytisine, an anesthetic agent. While these drugs did not reach the primary selection, their inclusion highlights the breadth of existing pharmaceuticals being explored for potential repurposing.
Leading researchers emphasize the necessity for cautious optimism and the critical importance of proceeding with robust clinical trials. Dr. Anne Corbett, Professor of Dementia Research at the University of Exeter, articulated this sentiment by stating, "Combating dementia requires a multifaceted research strategy, encompassing the intelligent utilization of existing knowledge alongside the pursuit of novel therapeutic agents. Drug repurposing represents an indispensable component of this comprehensive approach, enabling us to transform current medicines for one ailment into future treatments for another." She further underscored the preliminary nature of these findings, emphasizing, "It is crucial to highlight that these medications necessitate extensive further investigation before their utility in treating or preventing Alzheimer’s can be definitively established. The current priority is to conduct well-designed clinical trials to fully elucidate their therapeutic value and confirm their effectiveness."
Echoing this perspective, Professor Fiona Carragher, Chief Policy and Research Officer at the Alzheimer’s Society, conveyed a message of hope grounded in scientific advancement. "Dementia inflicts profound devastation on lives, yet we firmly believe that research holds the key to overcoming it," she stated. Professor Carragher drew a historical parallel, recalling the successful repurposing of aspirin, initially a pain reliever, to now play a role in reducing the risk of heart attack and stroke. "This," she continued, "is precisely the paradigm we aspire to replicate within the realm of dementia research, underscoring why drug repurposing stands as one of the most exhilarating and promising frontiers in our ongoing efforts."
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