Drug Development for Alzheimer's Disease: Recent Progress

Alzheimer's disease, the most common cause of dementia, is characterized by two major pathological hallmarks: amyloid plaques and neurofibrillary tangles. Based on these two indicators, an amyloid cascade hypothesis was proposed, and accordingly, most current therapeutic approaches are now focused on the removal of β-amyloid peptides (Aβ from the brain. Additionally, strategies for blocking tau hyperphosphorylation and aggregation have been suggested, including the development of drugs that can block the formation of tangles. However, there are no true disease-modifying drugs in the current market, though many drugs based on theories other than Aβ and tau pathology are under development. The purpose of this review was to provide information on the current development of AD drugs and to discuss the issues related to drug development

Clinical trials and late-stage drug development in Alzheimer’s disease: An appraisal from 1984 to 2014

The modern era of drug development for Alzheimer\u27s disease began with the proposal of the cholinergic hypothesis of memory impairment and the 1984 research criteria for Alzheimer\u27s disease. Since then, despite the evaluation of numerous potential treatments in clinical trials, only four cholinesterase inhibitors and memantine have shown sufficient safety and efficacy to allow marketing approval at an international level. Although this is probably because the other drugs tested were ineffective, inadequate clinical development methods have also been blamed for the failures. Here, we review the development of treatments for Alzheimer\u27s disease during the past 30 years, considering the drugs, potential targets, late‐stage clinical trials, development methods, emerging use of biomarkers and evolution of regulatory considerations in order to summarize advances and anticipate future developments. We have considered late‐stage Alzheimer\u27s disease drug development from 1984 to 2013, including individual clinical trials, systematic and qualitative reviews, meta‐analyses, methods, commentaries, position papers and guidelines. We then review the evolution of drugs in late clinical development, methods, biomarkers and regulatory issues. Although a range of small molecules and biological products against many targets have been investigated in clinical trials, the predominant drug targets have been the cholinergic system and the amyloid cascade. Trial methods have evolved incrementally: inclusion criteria have largely remained focused on mild‐to‐moderate Alzheimer\u27s disease criteria, recently extending to early or prodromal Alzheimer disease or ‘mild cognitive impairment due to Alzheimer\u27s disease’, for drugs considered to be disease modifying. The duration of trials has remained at 6–12 months for drugs intended to improve symptoms; 18‐ to 24‐month trials have been established for drugs expected to attenuate clinical course. Cognitive performance, activities of daily living, global change and severity ratings have persisted as the primary clinically relevant outcomes. Regulatory guidance and oversight have evolved to allow for enrichment of early‐stage Alzheimer\u27s disease trial samples using biomarkers and phase‐specific outcomes. In conclusion, validated drug targets for Alzheimer\u27s disease remain to be developed. Only drugs that affect an aspect of cholinergic function have shown consistent, but modest, clinical effects in late‐phase trials. There is opportunity for substantial improvements in drug discovery and clinical development methods

A turbulent decade for NSAIDs: update on current concepts of classification, epidemiology, comparative efficacy, and toxicity

Non-steroidal anti-inflammatory drugs (NSAIDs) represent a diverse class of drugs and are among the most commonly used analgesics for arthritic pain worldwide, though long-term use is associated with a spectrum of adverse effects. The introduction of cyclooxygenase-2-selective NSAIDs early in the last decade offered an alternative to traditional NSAIDs with similar efficacy and improved gastrointestinal tolerability; however, emerging concerns about cardiovascular safety resulted in the withdrawal of two agents (rofecoxib and valdecoxib) in the mid-2000s and, subsequently, in an overall reduction in NSAID use. It is now understood that all NSAIDs are associated with some varying degree of gastrointestinal and cardiovascular risk. Guidelines still recommend their use, but little is known of how patients use these agents. While strategies and guidelines aimed at reducing NSAID-associated complications exist, there is a need for evidence-based algorithms combining cardiovascular and gastrointestinal factors that can be used to aid treatment decisions at an individual patient level

Non-steroidal anti-inflammatory drugs as disease-modifying agents for Parkinson's disease : evidence from observational studies

This is the protocol for a review and there is no abstract. The objectives are as follows: We will address the following questions: 1) Do NSAIDs prevent the onset of Parkinson's disease(PD)? We will seek primary prevention trials and epidemiological studies examining the association between NSAIDs and PD to address this question. 2) Are NSAIDs neuroprotective in PD - do they slow the progression of disease once PD is established? We will seek secondary prevention trials to address this question. We will also explore any adverse effects of taking NSAIDs. 3) What are the adverse effects of taking NSAIDs in PD? We will use studies in question 2 above to examine this, along with any additional studies identified from the searching (including case studies and case series)

Cognitive function over time in the Alzheimer's Disease Anti-inflammatory Prevention Trial (ADAPT): results of a randomized, controlled trial of naproxen and celecoxib.

BackgroundObservational studies have shown reduced risk of Alzheimer dementia in users of nonsteroidal anti-inflammatory drugs.ObjectiveTo evaluate the effects of naproxen sodium and celecoxib on cognitive function in older adults.DesignRandomized, double-masked chemoprevention trial.SettingSix US memory clinics.ParticipantsMen and women aged 70 years and older with a family history of Alzheimer disease; 2117 of 2528 enrolled had follow-up cognitive assessment.InterventionsCelecoxib (200 mg twice daily), naproxen sodium (220 mg twice daily), or placebo, randomly allocated in a ratio of 1:1:1.5, respectively.Main outcome measuresSeven tests of cognitive function and a global summary score measured annually.ResultsLongitudinal analyses showed lower global summary scores over time for naproxen compared with placebo (- 0.05 SDs; P = .02) and lower scores on the Modified Mini-Mental State Examination over time for both treatment groups compared with placebo (- 0.33 points for celecoxib [P = .04] and - 0.36 points for naproxen [P = .02]). Restriction of analyses to measures collected from persons without dementia attenuated the treatment group differences. Analyses limited to measures obtained while participants were being issued study drugs produced results similar to the intention-to-treat analyses.ConclusionsUse of naproxen or celecoxib did not improve cognitive function. There was weak evidence for a detrimental effect of naproxen