At present, about 33·9 million people worldwide have Alzheimer's disease (AD), and prevalence is expected to triple over the next 40 years. The aim of this Review was to summarise the evidence regarding seven potentially modifiable risk factors for AD: diabetes, midlife hypertension, midlife obesity, smoking, depression, cognitive inactivity or low educational attainment, and physical inactivity. Additionally, we projected the effect of risk factor reduction on AD prevalence by calculating population attributable risks (the percent of cases attributable to a given factor) and the number of AD cases that might be prevented by risk factor reductions of 10% and 25% worldwide and in the USA. Together, up to half of AD cases worldwide (17·2 million) and in the USA (2·9 million) are potentially attributable to these factors. A 10-25% reduction in all seven risk factors could potentially prevent as many as 1·1-3·0 million AD cases worldwide and 184,000-492,000 cases in the USA.

The projected effect of risk factor reduction on Alzheimer's disease prevalence

An estimated 24 million people worldwide have dementia, the majority of whom are thought to have Alzheimer's disease. Thus, Alzheimer's disease represents a major public health concern and has been identified as a research priority. Although there are licensed treatments that can alleviate symptoms of Alzheimer's disease, there is a pressing need to improve our understanding of pathogenesis to enable development of disease-modifying treatments. Methods for improving diagnosis are also moving forward, but a better consensus is needed for development of a panel of biological and neuroimaging biomarkers that support clinical diagnosis. There is now strong evidence of potential risk and protective factors for Alzheimer's disease, dementia, and cognitive decline, but further work is needed to understand these better and to establish whether interventions can substantially lower these risks. In this Seminar, we provide an overview of recent evidence regarding the epidemiology, pathogenesis, diagnosis, and treatment of Alzheimer's disease, and discuss potential ways to reduce the risk of developing the disease.

SeminarAlzheimer's disease

Alzheimer mechanisms and therapeutic strategies.

There are a number of ways in which a clinical diagnosis of dementia of the Alzheimer type can be made – the application of clinical criteria is the commonest but ancillary techniques such as neuroima

Clinical Diagnosis of Alzheimer's Disease

https://www.cell.com/cell/pdf/S0092-8674(19)31007-4.pdf

Alzheimer Disease: An Update on Pathobiology and Treatment Strategies.

Context Amyloid-β peptide (Aβ 42 ) has been implicated in the pathogenesis of Alzheimer disease (AD). Tarenflurbil, a selective Aβ 42 -lowering agent, demonstrated encouraging results on cognitive and functional outcomes among mildly affected patients in an earlier phase 2 trial. Objective To determine the efficacy, safety, and tolerability of tarenflurbil. Design, Setting, and Patients A multicenter, randomized, double-blind, placebo-controlled trial enrolling patients with mild AD was conducted at 133 trial sites in the United States between February 21, 2005, and April 30, 2008. Concomitant treatment with cholinesterase inhibitors or memantine was permitted. Intervention Tarenflurbil, 800 mg, or placebo, administered twice a day. Main Outcome Measures Co-primary efficacy end points were the change from baseline to month 18 in total score on the subscale of the Alzheimer Disease Assessment Scale−Cognitive Subscale (ADAS-Cog, 80-point version) and Alzheimer Disease Cooperative Studies–activities of daily living (ADCS-ADL) scale. Additional prespecified slope analyses explored the possibility of disease modification. Results Of the 1684 participants randomized, 1649 were included in the analysis, and 1046 completed the trial. Tarenflurbil had no beneficial effect on the co-primary outcomes (difference in change from baseline to month 18 vs placebo, based on least squares means: 0.1 for ADAS-Cog; 95% CI, −0.9 to 1.1; P = .86 and −0.5 for ADCS-ADL; 95% CI, −1.9 to 0.9; P = .48) using an intent-to-treat analysis. No significant differences occurred in the secondary outcomes. The ADAS-Cog score decreased by 7.1 points over 18 months. The tarenflurbil group had a small increase in frequency of dizziness, anemia, and infections. Conclusion Tarenflurbil did not slow cognitive decline or the loss of activities of daily living in patients with mild AD. Trial Registration clinicaltrials.gov Identifier: NCT00105547

https://jamanetwork.com/journals/jama/articlepdf/185073/joc90137_2557_2564.pdf

Effect of tarenflurbil on cognitive decline and activities of daily living in patients with mild Alzheimer disease: a randomized controlled trial.

CONTEXT
Amyloid-beta peptide (Abeta(42)) has been implicated in the pathogenesis of Alzheimer disease (AD). Tarenflurbil, a selective Abeta(42)-lowering agent, demonstrated encouraging results on cognitive and functional outcomes among mildly affected patients in an earlier phase 2 trial.


OBJECTIVE
To determine the efficacy, safety, and tolerability of tarenflurbil.


DESIGN, SETTING, AND PATIENTS
A multicenter, randomized, double-blind, placebo-controlled trial enrolling patients with mild AD was conducted at 133 trial sites in the United States between February 21, 2005, and April 30, 2008. Concomitant treatment with cholinesterase inhibitors or memantine was permitted.


INTERVENTION
Tarenflurbil, 800 mg, or placebo, administered twice a day.


MAIN OUTCOME MEASURES
Co-primary efficacy end points were the change from baseline to month 18 in total score on the subscale of the Alzheimer Disease Assessment Scale-Cognitive Subscale (ADAS-Cog, 80-point version) and Alzheimer Disease Cooperative Studies-activities of daily living (ADCS-ADL) scale. Additional prespecified slope analyses explored the possibility of disease modification.


RESULTS
Of the 1684 participants randomized, 1649 were included in the analysis, and 1046 completed the trial. Tarenflurbil had no beneficial effect on the co-primary outcomes (difference in change from baseline to month 18 vs placebo, based on least squares means: 0.1 for ADAS-Cog; 95% CI, -0.9 to 1.1; P = .86 and -0.5 for ADCS-ADL; 95% CI, -1.9 to 0.9; P = .48) using an intent-to-treat analysis. No significant differences occurred in the secondary outcomes. The ADAS-Cog score decreased by 7.1 points over 18 months. The tarenflurbil group had a small increase in frequency of dizziness, anemia, and infections.


CONCLUSION
Tarenflurbil did not slow cognitive decline or the loss of activities of daily living in patients with mild AD.


TRIAL REGISTRATION
clinicaltrials.gov Identifier: NCT00105547.

Effect of Tarenflurbil on Cognitive Decline and Activities of Daily Living in Patients With Mild Alzheimer Disease

Summary Background The amyloid-β peptide Aβ 42 has been implicated in the pathogenesis of Alzheimer's disease (AD). We aimed to test the effects of tarenflurbil, a selective Aβ 42 -lowering agent (SALA), on cognition and function in patients with mild to moderate AD. Methods 210 patients living in the community who had a mini-mental state examination (MMSE) score of 15–26 were randomly assigned to receive tarenflurbil twice per day (400 mg [n=69] or 800 mg [n=70]) or placebo (n=71) for 12 months in a phase II, multicentre, double-blind study. Primary efficacy outcomes were the AD assessment scale cognitive subscale (ADAS-cog), the Alzheimer's Disease Cooperative Study activities of daily living scale (ADCS-ADL), and the clinical dementia rating sum of boxes (CDR-sb). In a 12-month extended treatment phase, patients who had received tarenflurbil continued to receive the same dose, and patients who had received placebo were randomly assigned to tarenflurbil at 800 mg or 400 mg twice per day. Primary efficacy analyses were done by intention to treat. This trial is registered with Health Canada (084527) and the Medicines and Healthcare products Regulatory Agency in the UK (20365/0001/A 69316). Findings A prespecified interaction analysis revealed that patients with mild AD (baseline MMSE 20–26) and moderate AD (baseline MMSE 15–19) responded differently to tarenflurbil in the ADAS-cog and the ADCS-ADL (p≥0·10); therefore, these groups were analysed separately. Patients with mild AD in the 800 mg tarenflurbil group had lower rates of decline than did those in the placebo group in activities of daily living (ADCS-ADL difference in slope 3·98 [95% CI 0·33 to 7·62] points per year, effect size [reduction from placebo decline rate] 46·4%, Cohen's d 0·45; p=0·033) and global function (CDR-sb difference −0·80 [−1·57 to −0·03] points per year, effect size 35·7%, Cohen's d 0·42; p=0·042); slowing of cognitive decline did not differ significantly (ADAS-cog difference −1·36 [−4·07 to 1·36] points per year, effect size 33·7%, Cohen's d 0·20; p=0·327). In patients with moderate AD, 800 mg tarenflurbil twice per day had no significant effects on ADCS-ADL and ADAS-cog and had a negative effect on CDR-sb (−52%, Cohen's d −1·08; p=0·003). The most common adverse events were diarrhoea (in seven, nine, and five patients in the 800 mg, 400 mg, and placebo groups, respectively), nausea (in seven, seven, and four patients), and dizziness (in five, nine, and four patients). Patients with mild AD who were in the 800 mg tarenflurbil group for 24 months had lower rates of decline for all three primary outcomes than did patients who were in the placebo group for months 0–12 and a tarenflurbil group for months 12–24 (all p Interpretation 800 mg tarenflurbil twice per day was well tolerated for up to 24 months of treatment, with evidence of a dose-related effect on measures of daily activities and global function in patients with mild AD. Funding Myriad Pharmaceuticals.

https://www.thelancet.com/pdfs/journals/laneur/PIIS1474-4422(08)70090-5.pdf

Efficacy and safety of tarenflurbil in mild to moderate Alzheimer's disease: a randomised phase II trial

To evaluate the safety and tolerability and pharmacokinetic properties of R-flurbiprofen (Tarenflurbil) in normal elderly individuals and to determine the effect of the drug on amyloid beta 42 (Abeta42) levels, we conducted a double-blind, placebo-controlled study of 48 healthy subjects aged 55 to 80. Three successive cohorts were randomized to doses of 400, 800, or 1600 mg/d, or placebo, given as 2 divided doses for 21 days. Blood and cerebrospinal fluid were collected for pharmacokinetic studies and measurement of Abeta levels at baseline and on day 21. R-flurbiprofen was well-tolerated at all 3 doses. The compound penetrated the blood-brain barrier in a dose-dependent manner. From baseline to 21 days, comparisons between study groups revealed no significant differences in changes of cerebrospinal fluid Abeta42 levels and no significant differences in changes of plasma Abeta42 levels at the time of trough drug level at 21 days of treatment. Further analysis of drug concentration-response for plasma samples showed that at the time of peak plasma concentration, higher plasma drug concentration was related to lower Abeta42 plasma levels (P=0.016). R-flurbiprofen had an excellent safety profile and showed dose-dependent central nervous system penetration. Exploratory analyses of plasma Abeta and peak drug levels suggested a short-term effect in plasma that warrants independent verification. The safety, tolerability, and pharmacokinetic profile of R-flurbiprofen in these older individuals support the ongoing studies of this compound in patients with Alzheimer disease.

Safety, Tolerability, Pharmacokinetics, and Aβ Levels After Short-term Administration of R-flurbiprofen in Healthy Elderly Individuals

MPC-6827 (Azixa) is a small-molecule microtubule-destabilizing agent that binds to the same (or nearby) sites on β-tubulin as colchicine. This phase I study was designed to determine the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), and pharmacokinetics (PK) of MPC-6827 in patients with solid tumors. Patients with advanced/metastatic cancer were treated with once-weekly, 1- to 2-hour intravenous administration of MPC-6827 for 3 consecutive weeks every 28 days (1 cycle). Dose escalation began with 0.3, 0.6, 1, and 1.5 mg/m2, with subsequent increments of 0.6 mg/m2 until the MTD was determined. A 3 + 3 design was used. Pharmacokinetics of MPC-6827 and its metabolite MPI-0440627 were evaluated. Forty-eight patients received therapy; 79 cycles were completed (median, 1; range, 1–10). The most common adverse events were nausea, fatigue, flushing, and hyperglycemia. The DLT was nonfatal grade 3 myocardial infarction at 3.9 mg/m2 (1/6 patients) and at 4.5 mg/m2 (1/7 patients). The MTD was determined to be 3.3 mg/m2 (0/13 patients had a DLT). Five (10.4%) of the 48 patients achieved stable disease (Response Evaluation Criteria in Solid Tumors) for 4 months or greater. MPC-6827 has a high volume of distribution and clearance. Half-life ranged from 3.8 to 7.5 hours. In conclusion, MPC-6827 administered intravenously over 2 hours at a dose of 3.3 mg/m2 once weekly for 3 weeks every 28 days was safe in patients with heavily pretreated cancer. Clinical trials with MPC-6827 and chemotherapy are ongoing. Mol Cancer Ther; 9(12); 3410–9. ©2010 AACR.

https://mct.aacrjournals.org/content/molcanther/9/12/3410.full.pdf

Edward Swabb

Papers

Effect of tarenflurbil on cognitive decline and activities of daily living in patients with mild Alzheimer disease: a randomized controlled trial.

Effect of Tarenflurbil on Cognitive Decline and Activities of Daily Living in Patients With Mild Alzheimer Disease

Efficacy and safety of tarenflurbil in mild to moderate Alzheimer's disease: a randomised phase II trial

Safety, Tolerability, Pharmacokinetics, and Aβ Levels After Short-term Administration of R-flurbiprofen in Healthy Elderly Individuals

Phase I clinical trial of MPC-6827 (Azixa), a microtubule destabilizing agent, in patients with advanced cancer