Preserved cognitive function after 12 months of treatment with rivastigmine in mild Alzheimer's disease in comparison with untreated AD and MCI patients

Glycoproteins as diagnostic and prognostic biomarkers for neurodegenerative diseases: A glycoproteomic approach

Neurodegenerative diseases (NDs) are incurable and can develop progressively debilitating disorders, including dementia and ataxias. Alzheimer's disease and Parkinson's disease are the most common NDs that mainly affect the elderly people. There is an urgent need to develop new diagnostic tools so that patients can be accurately stratified at an early stage. As a common post-translational modification, protein glycosylation plays a key role in physiological and pathological processes. The abnormal changes in glycosylation are associated with the altered biological pathways in NDs. The pathogenesis-related proteins, like amyloid-β and microtubule-associated protein tau, have altered glycosylation. Importantly, specific glycosylation changes in cerebrospinal fluid, blood and urine are valuable for revealing neurodegeneration in the early stages. This review describes the emerging biomarkers based on glycoproteomics in NDs, highlighting the potential applications of glycoprotein biomarkers in the early detection of diseases, monitoring of the disease progression, and measurement of the therapeutic responses. The mass spectrometry-based strategies for characterizing glycoprotein biomarkers are also introduced.

Strategies for the use of Ginkgo biloba extract, EGb 761® , in the treatment and management of mild cognitive impairment in Asia: Expert consensus

BACKGROUND

Mild cognitive impairment (MCI) is a neurocognitive state between normal cognitive aging and dementia, with evidence of neuropsychological changes but insufficient functional decline to warrant a diagnosis of dementia. Individuals with MCI are at increased risk for progression to dementia; and an appreciable proportion display neuropsychiatric symptoms (NPS), also a known risk factor for dementia. Cerebrovascular disease (CVD) is thought to be an underdiagnosed contributor to MCI/dementia. The Ginkgo biloba extract, EGb 761® , is increasingly being used for the symptomatic treatment of cognitive disorders with/without CVD, due to its known neuroprotective effects and cerebrovascular benefits.

AIMS

To present consensus opinion from the ASian Clinical Expert group on Neurocognitive Disorders (ASCEND) regarding the role of EGb 761® in MCI.

MATERIALS & METHODS

The ASCEND Group reconvened in September 2019 to present and critically assess the current evidence on the general management of MCI, including the efficacy and safety of EGb 761® as a treatment option.

RESULTS

EGb 761® has demonstrated symptomatic improvement in at least four randomized trials, in terms of cognitive performance, memory, recall and recognition, attention and concentration, anxiety, and NPS. There is also evidence that EGb 761® may help delay progression from MCI to dementia in some individuals.

DISCUSSION

EGb 761® is currently recommended in multiple guidelines for the symptomatic treatment of MCI. Due to its beneficial effects on cerebrovascular blood flow, it is reasonable to expect that EGb 761® may benefit MCI patients with underlying CVD.

CONCLUSION

As an expert group, we suggest it is clinically appropriate to incorporate EGb 761® as part of the multidomain intervention for MCI.

Early Stage Glycosylation Biomarkers in Alzheimer's Disease

Alzheimer's disease (AD) is of great cause for concern in our ageing population, which currently lacks diagnostic tools to permit accurate and timely diagnosis for affected individuals. The development of such tools could enable therapeutic interventions earlier in the disease course and thus potentially reducing the debilitating effects of AD. Glycosylation is a common, and important, post translational modification of proteins implicated in a host of disease states resulting in a complex array of glycans being incorporated into biomolecules. Recent investigations of glycan profiles, in a wide range of conditions, has been made possible due to technological advances in the field enabling accurate glycoanalyses. Amyloid beta (Aβ) peptides, tau protein, and other important proteins involved in AD pathogenesis, have altered glycosylation profiles. Crucially, these abnormalities present early in the disease state, are present in the peripheral blood, and help to distinguish AD from other dementias. This review describes the aberrant glycome in AD, focusing on proteins implicated in development and progression, and elucidates the potential of glycome aberrations as early stage biomarkers of AD.

WITHDRAWN: Revisiting the cholinergic hypothesis in Alzheimer's disease: Emerging evidence from translational and clinical research

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Rivastigmine for Alzheimer's disease

BACKGROUND

Alzheimer's disease is the commonest cause of dementia affecting older people. One of the therapeutic strategies aimed at ameliorating the clinical manifestations of Alzheimer's disease is to enhance cholinergic neurotransmission in the brain by the use of cholinesterase inhibitors to delay the breakdown of acetylcholine released into synaptic clefts. Tacrine, the first of the cholinesterase inhibitors to undergo extensive trials for this purpose, was associated with significant adverse effects including hepatotoxicity. Other cholinesterase inhibitors, including rivastigmine, with superior properties in terms of specificity of action and lower risk of adverse effects have since been introduced. Rivastigmine has received approval for use in 60 countries including all member states of the European Union and the USA.

OBJECTIVES

To determine the clinical efficacy and safety of rivastigmine for patients with dementia of Alzheimer's type.

SEARCH METHODS

We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register, on 2 March 2015 using the terms: Rivastigmine OR  exelon OR ENA OR "SDZ ENA 713". ALOIS contains records of clinical trials identified from monthly searches of a number of major healthcare databases (Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS), numerous trial registries and grey literature sources.

SELECTION CRITERIA

We included all unconfounded, double-blind, randomised, controlled trials in which treatment with rivastigmine was administered to patients with dementia of the Alzheimer's type for 12 weeks or more and its effects compared with those of placebo in a parallel group of patients, or where two formulations of rivastigmine were compared.

DATA COLLECTION AND ANALYSIS

One review author (JSB) applied the study selection criteria, assessed the quality of studies and extracted data.

MAIN RESULTS

A total of 13 trials met the inclusion criteria of the review. The trials had a duration of between 12 and 52 weeks. The older trials tested a capsule form with a dose of up to 12 mg/day. Trials reported since 2007 have tested continuous dose transdermal patch formulations delivering 4.6, 9.5 and 17.7 mg/day.Our main analysis compared the safety and efficacy of rivastigmine 6 to 12 mg/day orally or 9.5 mg/day transdermally with placebo.Seven trials contributed data from 3450 patients to this analysis. Data from another two studies were not included because of a lack of information and methodological concerns. All the included trials were multicentre trials and recruited patients with mild to moderate Alzheimer's disease with a mean age of about 75 years. All had low risk of bias for randomisation and allocation but the risk of bias due to attrition was unclear in four studies, low in one study and high in two studies.After 26 weeks of treatment rivastigmine compared to placebo was associated with better outcomes for cognitive function measured with the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) score (mean difference (MD) -1.79; 95% confidence interval (CI) -2.21 to -1.37, n = 3232, 6 studies) and the Mini-Mental State Examination (MMSE) score (MD 0.74; 95% CI 0.52 to 0.97, n = 3205, 6 studies), activities of daily living (SMD 0.20; 95% CI 0.13 to 0.27, n = 3230, 6 studies) and clinician rated global impression of changes, with a smaller proportion of patients treated with rivastigmine experiencing no change or a deterioration (OR 0.68; 95% CI 0.58 to 0.80, n = 3338, 7 studies).Three studies reported behavioural change, and there were no differences compared to placebo (standardised mean difference (SMD) -0.04; 95% CI -0.14 to 0.06, n = 1529, 3 studies). Only one study measured the impact on caregivers using the Neuropsychiatric Inventory-Caregiver Distress (NPI-D) scale and this found no difference between the groups (MD 0.10; 95% CI -0.91 to 1.11, n = 529, 1 study). Overall, participants who received rivastigmine were about twice as likely to withdraw from the trials (odds ratio (OR) 2.01, 95% CI 1.71 to 2.37, n = 3569, 7 studies) or to experience an adverse event during the trials (OR 2.16, 95% CI 1.82 to 2.57, n = 3587, 7 studies).

AUTHORS' CONCLUSIONS

Rivastigmine (6 to 12 mg daily orally or 9.5 mg daily transdermally) appears to be beneficial for people with mild to moderate Alzheimer's disease. In comparisons with placebo, better outcomes were observed for rate of decline of cognitive function and activities of daily living, although the effects were small and of uncertain clinical importance. There was also a benefit from rivastigmine on the outcome of clinician's global assessment. There were no differences between the rivastigmine group and placebo group in behavioural change or impact on carers. At these doses the transdermal patch may have fewer side effects than the capsules but has comparable efficacy. The quality of evidence is only moderate for all of the outcomes reviewed because of a risk of bias due to dropouts. All the studies with usable data were industry funded or sponsored. This review has not examined economic data.

Rivastigmine for Alzheimer's disease

BACKGROUND

Alzheimer's disease is the commonest cause of dementia affecting older people. One of the therapeutic strategies aimed at ameliorating the clinical manifestations of Alzheimer's disease is to enhance cholinergic neurotransmission in the brain by the use of cholinesterase inhibitors to delay the breakdown of acetylcholine released into synaptic clefts. Tacrine, the first of the cholinesterase inhibitors to undergo extensive trials for this purpose, was associated with significant adverse effects including hepatotoxicity. Other cholinesterase inhibitors, including rivastigmine, with superior properties in terms of specificity of action and lower risk of adverse effects have since been introduced. Rivastigmine has received approval for use in 60 countries including all member states of the European Union and the USA.

OBJECTIVES

To determine the clinical efficacy and safety of rivastigmine for patients with dementia of Alzheimer's type.

SEARCH METHODS

We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register, on 2 March 2015 using the terms: Rivastigmine OR  exelon OR ENA OR "SDZ ENA 713". ALOIS contains records of clinical trials identified from monthly searches of a number of major healthcare databases (Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS), numerous trial registries and grey literature sources.

SELECTION CRITERIA

We included all unconfounded, double-blind, randomised, controlled trials in which treatment with rivastigmine was administered to patients with dementia of the Alzheimer's type for 12 weeks or more and its effects compared with those of placebo in a parallel group of patients, or where two formulations of rivastigmine were compared.

DATA COLLECTION AND ANALYSIS

One review author (JSB) applied the study selection criteria, assessed the quality of studies and extracted data.

MAIN RESULTS

A total of 13 trials met the inclusion criteria of the review. The trials had a duration of between 12 and 52 weeks. The older trials tested a capsule form with a dose of up to 12 mg/day. Trials reported since 2007 have tested continuous dose transdermal patch formulations delivering 4.6, 9.5 and 17.7 mg/day.Our main analysis compared the safety and efficacy of rivastigmine 6 to 12 mg/day orally or 9.5 mg/day transdermally with placebo.Seven trials contributed data from 3450 patients to this analysis. Data from another two studies were not included because of a lack of information and methodological concerns. All the included trials were multicentre trials and recruited patients with mild to moderate Alzheimer's disease with a mean age of about 75 years. All had low risk of bias for randomisation and allocation but the risk of bias due to attrition was unclear in four studies, low in one study and high in two studies.After 26 weeks of treatment rivastigmine compared to placebo was associated with better outcomes for cognitive function measured with the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) score (mean difference (MD) -1.79; 95% confidence interval (CI) -2.21 to -1.37, n = 3232, 6 studies) and the Mini-Mental State Examination (MMSE) score (MD 0.74; 95% CI 0.52 to 0.97, n = 3205, 6 studies), activities of daily living (SMD 0.20; 95% CI 0.13 to 0.27, n = 3230, 6 studies) and clinician rated global impression of changes, with a smaller proportion of patients treated with rivastigmine experiencing no change or a deterioration (OR 0.68; 95% CI 0.58 to 0.80, n = 3338, 7 studies).Three studies reported behavioural change, and there were no differences compared to placebo (standardised mean difference (SMD) -0.04; 95% CI -0.14 to 0.06, n = 1529, 3 studies). Only one study measured the impact on caregivers using the Neuropsychiatric Inventory-Caregiver Distress (NPI-D) scale and this found no difference between the groups (MD 0.10; 95% CI -0.91 to 1.11, n = 529, 1 study). Overall, participants who received rivastigmine were about twice as likely to withdraw from the trials (odds ratio (OR) 2.01, 95% CI 1.71 to 2.37, n = 3569, 7 studies) or to experience an adverse event during the trials (OR 2.16, 95% CI 1.82 to 2.57, n = 3587, 7 studies).

AUTHORS' CONCLUSIONS

Rivastigmine (6 to 12 mg daily orally or 9.5 mg daily transdermally) appears to be beneficial for people with mild to moderate Alzheimer's disease. In comparisons with placebo, better outcomes were observed for rate of decline of cognitive function and activities of daily living, although the effects were small and of uncertain clinical importance. There was also a benefit from rivastigmine on the outcome of clinician's global assessment. There were no differences between the rivastigmine group and placebo group in behavioural change or impact on carers. At these doses the transdermal patch may have fewer side effects than the capsules but has comparable efficacy. The quality of evidence is only moderate for all of the outcomes reviewed because of a risk of bias due to dropouts. All the studies with usable data were industry funded or sponsored. This review has not examined economic data.

Treatment effects in multiple cognitive domains in Alzheimer's disease: a two-year cohort study

Introduction

Despite widespread use of second-generation cholinesterase inhibitors for the symptomatic treatment of Alzheimer’s disease (AD), little is known about the long term effects of cholinergic treatment on global cognitive function and potential specific effects in different cognitive domains. The objectives of this study were to determine the association between cholinergic treatment and global cognitive function over one and two years in a cohort of patients with mild or moderate AD and identify potential differences in domain-specific cognitive outcomes within this cohort.

Methods

A cohort of patients meeting the revised National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for mild or moderate AD, including patients both on treatment with a cholinesterase inhibitor and untreated controls (treated = 65, untreated = 65), were recruited from the Cognitive Neurology Clinic at Sunnybrook Health Sciences Centre, as part of the Sunnybrook Dementia Study. Patients were followed for one to two years and underwent standardized neuropsychological assessments to evaluate global and domain-specific cognitive function. Associations between cholinesterase inhibitor use and global and domain-specific cognitive outcome measures at one and two years of follow-up were estimated using mixed model linear regression, adjusting for age, education, and baseline mini mental state examination (MMSE).

Results

At one year, treated patients showed significantly less decline in global cognitive function, and treatment and time effects across tests of executive and visuospatial function. At two years, there was a significant trend towards less decline in global cognition for treated patients. Moreover, treated patients showed significant treatment and time effects across tests of executive functioning, memory, and visuospatial function.

Conclusions

The present study offers two important contributions to knowledge of the effectiveness of cholinesterase inhibitor treatment in patients with mild-moderate AD: 1) that second-generation cholinesterase inhibitors demonstrate long-term effectiveness for reducing global cognitive decline over one to two years of follow-up, and 2) that decline in function for cognitive domains, including executive function, memory, and visuospatial skill that are primarily mediated by frontal networks and by the cholinergic system, rather than memory, may be slowed by treatment targeting the cholinergic system.

Rivastigmine for subcortical vascular dementia

Rivastigmine is a second-generation cholinesterase inhibitor with selectivity for the CNS, with capacity to inhibit both acetylcholinesterase and butyrylcholinesterase. Rivastigmine is currently approved for the treatment of mild-to-moderate Alzheimer's disease. In addition to its effects on cognition and activities of daily living, rivastigmine appears to be useful in preventing and controlling behavioral and neuropsychiatric manifestations in Alzheimer's disease and dementia with Lewy bodies. This drug profile could be potentially useful in patients with subcortical vascular dementia who often present these symptoms. Small open-label studies of patients with subcortical vascular dementia showed that rivastigmine improved attention, executive function, apathy and other behavioral deficits. Rivastigmine appears to be a promising agent in vascular dementia but its effects remain to be established in double-blind, placebo-controlled clinical trials.

Beyond symptomatic therapy: a re-examination of acetylcholinesterase inhibitors in Alzheimer’s disease

Acetylcholinesterase inhibitors (AChEIs) are generally regarded as palliative treatments for Alzheimer's disease that slow the progression of dementia symptoms without altering Alzheimer's disease's underlying pathogenic mechanisms. This concept is based on inference rather than evidence, and has limited the scope and persistence of AChEI use in clinical practice. Recent preclinical studies demonstrate that AChEIs exhibit a number of biological effects in addition to cholinesterase inhibition. A broader understanding of the possible mechanisms of action of AChEIs in Alzheimer's disease could result in more effective use and assist in the development of new and improved therapies. The available evidence brings into question the prevailing view that AChEIs are exclusively symptomatic treatments and supports the use of these agents persistently throughout the course of Alzheimer's disease.

Zingipain, a ginger protease with acetylcholinesterase inhibitory activity

In order to search for new acetylcholinesterase inhibitors (AChEIs), 15 Zingiberaceae plants were tested for AChEI activity in rhizome extracts. The crude homogenate and ammonium sulfate cut fraction of Zingiber officinale contained a significant AChEI activity. Eighty percent saturation ammonium sulfate precipitation and diethylaminoethyl cellulose ion exchange chromatography (unbound fraction) enriched the protein to a single band on nondenaturing and reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (approximately 33.5 kDa). Gelatin-degrading zymography showed that the AChEI-containing band also contained cysteine protease activity. The AChEI activity was largely stable between -20 and 60 °C (at least over 120 min) and over a broad pH range (2-12). The AChEI activity was stimulated strongly by Mn(2+) and Cu(2+) at 1-10 mM and weakly by Ca(2+), Fe(2+), Mg(2+), and Zn(2+) at 1 mM, but was inhibited at 10 mM. In contrast, Hg(2+) and ethylenediaminetetraacetic acid were very and moderately strongly inhibitory, respectively. In-gel tryptic digestion with liquid chromatography-tandem mass spectroscopy resolution revealed two heterogeneous peptides, a 16-amino-acid-long fragment with 100 % similarity to zingipain-1, which is a cysteine protease from Z. officinale, and a 9-amino-acid-long fragment that was 100 % identical to actinidin Act 2a, suggesting that the preparation was heterogeneous. AChEI exhibited noncompetitive inhibition of AChE for the hydrolysis of acetylthiocholine iodide with a K(i) value of 9.31 mg/ml.

Current and future treatments for Alzheimer's disease

Alzheimer's dementia (AD) is increasingly being recognized as one of the most important medical and social problems in older people in industrialized and non-industrialized nations. To date, only symptomatic treatments exist for this disease, all trying to counterbalance the neurotransmitter disturbance. Three cholinesterase inhibitors (CIs) are currently available and have been approved for the treatment of mild to moderate AD. A further therapeutic option available for moderate to severe AD is memantine, an N-methyl-D-aspartate receptor noncompetitive antagonist. Treatments capable of stopping or at least effectively modifying the course of AD, referred to as 'disease-modifying' drugs, are still under extensive research. To block the progression of the disease they have to interfere with the pathogenic steps responsible for the clinical symptoms, including the deposition of extracellular amyloid β plaques and intracellular neurofibrillary tangle formation, inflammation, oxidative damage, iron deregulation and cholesterol metabolism. In this review we discuss current symptomatic treatments and new potential disease-modifying therapies for AD that are currently being studied in phase I-III trials.

Anti-aging herbal medicine--how and why can they be used in aging-associated neurodegenerative diseases?

Aging is a universal biological process that leads to progressive and deleterious changes in organisms. From ancient time, mankind has already interested in preventing and keeping ourselves young. Anti-aging study is certainly not a new research area. Nowadays, the meaning of anti-aging has been changed from simply prolonging lifespan to increasing health span, which emphasizes more on the quality of life. This is the concept of healthy aging and prevention of pathological aging, which is associated with diseases. Keeping our brain functions as in young age is an important task for neuroscientists to prevent aging-associated neurological disorders, such as Alzheimer's diseases (AD) and Parkinson's disease (PD). The causes of these diseases are not fully understood, but it is believed that these diseases are affected by multiple factors. Neurodegenerative diseases can be cross-linked with a number of aging-associated conditions. Based on this, a holistic approach in anti-aging research seems to be more reasonable. Herbal medicine has a long history in Asian countries. It is believed that many of the medicinal herbs have anti-aging properties. Recent studies have shown that some medicinal herbs are effective in intervention or prevention of aging-associated neurological disorders. In this review, we use wolfberry and ginseng as examples to elaborate the properties of anti-aging herbs. The characteristics of medicinal herbs, especially their applications in different disease stages (prevention and intervention) and multi-targets properties, allow them to be potential anti-aging intervention in prevention and treatment of the aging-associated neurological disorders.

Differential levels of apolipoprotein E and butyrylcholinesterase show strong association with pathological signs of Alzheimer's disease in the brain in vivo

Recently, we reported that 3 of the known risk factors of Alzheimer's disease (AD), i.e., advanced age, apolipoprotein E (ApoE) ε4, and female gender, are associated with differential levels of ApoE proteins and butyrylcholinesterase (BuChE) in the cerebrospinal fluid (CSF) of AD patients. The ApoE ε4 allele and certain BuChE polymorphisms synergistically affect the conversion rate of mild cognitive impairment (MCI) to AD. Here, we investigated interrelationships between ApoE and BuChE levels, and pathological markers of AD in vivo. CSF from patients with probable AD, assessed for cerebral glucose metabolism (CMRglc; n = 50) and Pittsburgh compound B (PIB) retention (β-amyloid [Aβ] load, n = 29) by positron emission tomography (PET), was used for measurement of BuChE, ApoE, Aβ, tau, phosphorylated tau (P-tau) and interleukin-1β (IL-1β) levels. Levels of ApoE and BuChE strongly correlated with CMRglc (fluorodeoxyglucose [FDG]-PET, r = 0.54, p < 0.0001, n = 50), cerebral Aβ load (PIB retention, r = 0.73, p < 0.0001, n = 29), and CSF P-tau (r = 0.73, p < 0.0001, n = 33). High ApoE protein was tied to low CMRglc and high PIB retention and P-tau. BuChE levels had opposite relationships. Other CSF covariates were levels of interleukin-1β and Aβ(42) peptide. The pattern of the patients' cognitive Z-scores strongly supported these observations. High ApoE protein was also linked to changes in 3 of the biodynamic properties of BuChE. In vitro analysis indicated that high ApoE protein levels were related to an increased pool of dormant BuChE molecules with an abnormally high intrinsic catalytic rate in CSF, which was "turned on" by excess Aβ peptides. The findings suggest that abnormally high levels of ApoE may play a causative role in the pathological events of AD, particularly those involving the early cholinergic deficit in the AD brain, through modulation of cholinesterases activities, hence disturbing the acetylcholine-dependent activity of neurons and nonexcitable cells such as glial cells.

Cholinesterase inhibitors in Alzheimer's disease and Lewy body spectrum disorders: the emerging pharmacogenetic story

This review provides an update on the current state of pharmacogenetic research in the treatment of Alzheimer's disease (AD) and Lewy body disease (LBD) as it pertains to the use of cholinesterase inhibitors (ChEI). AD and LBD are first reviewed from clinical and pathophysiological perspectives. This is followed by a discussion of ChEIs used in the symptomatic treatment of these conditions, focusing on their unique and overlapping pharmacokinetic and pharmacodynamic profiles, which can be used to identify candidate genes for pharmacogenetics studies. The literature published to date is then reviewed and limitations are discussed. This is followed by a discussion of potential endophenotypes which may help to refine future pharmacogenetic studies of response and adverse effects to ChEIs.

Rivastigmine for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the commonest cause of dementia affecting older people. One of the therapeutic strategies aimed at ameliorating the clinical manifestations of Alzheimer's disease is to enhance cholinergic neurotransmission in relevant parts of the brain by the use of cholinesterase inhibitors to delay the breakdown of acetylcholine released into synaptic clefts. Tacrine, the first of the cholinesterase inhibitors to undergo extensive trials for this purpose, was associated with significant adverse effects including hepatotoxicity. Other cholinesterase inhibitors, including rivastigmine, with superior properties in terms of specificity of action and low risk of adverse effects, have now been introduced. Rivastigmine has received approval for use in 60 countries including all member states of the European Union and the USA.

OBJECTIVES

To determine the clinical efficacy and safety of rivastigmine for patients with dementia of Alzheimer's type.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 27 March 2008 using the terms: Rivastigmine OR exelon OR ENA OR "SDZ ENA 713" . The CDCIG Specialized Register contains records from all major health care databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many clinical trials registries and grey literature sources.

SELECTION CRITERIA

All unconfounded, double-blind, randomized trials in which treatment with rivastigmine was administered to patients with dementia of the Alzheimer's type for more than two weeks and its effects compared with those of placebo in a parallel group of patients.

DATA COLLECTION AND ANALYSIS

One reviewer (JSB) applied study selection criteria, assessed the quality of studies and extracted data.

MAIN RESULTS

Nine trials, involving 4775 participants, were included in the analyses. Use of rivastigmine in high doses was associated with statistically significant benefits on several measures. High-dose rivastigmine (6 to 12 mg daily) was associated with a two-point improvement in cognitive function on the ADAS-Cog score compared with placebo (weighted mean difference -1.99, 95% confidence interval -2.49 to -1.50, on an intention-to-treat basis) and a 2.2 point improvement in activities of daily living assessed on the Progressive Deterioration Scale (weighted mean difference -2.15, 95% confidence interval -3.16 to -1.13, on an intention-to-treat basis) at 26 weeks. At lower doses (4 mg daily or lower) differences were in the same direction but were statistically significant only for cognitive function. There were statistically significantly higher numbers of events of nausea, vomiting, diarrhoea, anorexia, headache, syncope, abdominal pain and dizziness among patients taking high-dose rivastigmine than among those taking placebo. There was some evidence that adverse events might be less common with more frequent, smaller doses of rivastigmine. The 2008 update includes a new study testing two types of rivastigmine transdermal patch, one delivering a higher dose than previously tested (17.4 mg/day) and a smaller patch delivering 9.6 mg/day. The efficacy of the smaller patch was not significantly different compared with the capsules of similar daily dose, but was associated with significantly fewer adverse events of nausea, vomiting, dizziness and asthenia. The efficacy of the larger patch was not significantly different compared with the smaller patch, but the smaller patch was associated with significantly fewer adverse events of nausea, vomiting, weight loss and dizziness. There appears to be advantages associated with the smaller patch compared with both the higher dose patch and the 6-12 mg/day capsules.

AUTHORS' CONCLUSIONS

Rivastigmine appears to be beneficial for people with mild to moderate Alzheimer's disease. In comparisons with placebo, improvements were seen in the rate of decline of cognitive function, activities of daily living, and severity of dementia with daily doses of 6 to 12 mg. Adverse events were consistent with the cholinergic actions of the drug. A transdermal patch has been tested in one trial, and there is evidence that the lower dose smaller patch is associated with fewer side effects than the capsules or the higher dose larger patch and has comparable efficacy to both. This review has not examined economic data.

Improvement of spontaneous speech in early stage Alzheimer's with rivastigmine

OBJECTIVES

Placebo-controlled trials have shown that rivastigmine can delay cognitive deterioration in patients with mild to moderate Alzheimer's disease (AD). Benefits on cognitive functioning, as measured with the ADAS-Cog, occur on a daily dose of 6-12 mg when used for at least 6 months. The effect of rivastigmine on the adequacy of spontaneous speech is unknown. This study aimed to (i) compare the spontaneous speech of AD patients with the spontaneous speech of persons with normal cognition, (ii) compare the spontaneous speech of the same group of AD patients before and after treatment with rivastigmine.

METHODS

Spontaneous speech of AD patients (n=9) was compared with that of healthy elderly volunteers (n=8). In the patient group, spontaneous speech was analysed before and after treatment with rivastigmine.

RESULTS

Before treatment, 100% discrimination was found between the spontaneous speech of AD patients and of healthy volunteers based on two linguistic parameters: empty words and compound sentences. After treatment with rivastigmine the spontaneous speech of the AD patients improved on these two variables, while the ADAS-Cog scores decreased. Mean interval between the two spontaneous speech samples was 8.89 months.

CONCLUSION

Assessment of spontaneous speech might be a valid parameter to discriminate between normal cognition and AD, and to evaluate the effects of anti-AD medication.

Present and prospective clinical therapeutic regimens for Alzheimer's disease

Alzheimer's disease (AD) is an incurable neurodegenerative disorder that produces cognitive impairments that increase in severity as the disease progresses. The clinical symptoms are related to the presence of neuritic plaques and neurofibrillary tangles in the cerebral cortex which represent the pathophysiological hallmarks of AD. The debilitating nature of the disease can result in clinical burden for the patient, emotional strain for those that care for patients with Alzheimer's, and significant financial burden to society. The goals of current treatments, such as cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonist, are to reduce the severity or slow the progression of cognitive symptoms. Although these treatments have demonstrated modest clinical benefit, they are unable to prevent, prohibit, or reverse the underlying pathophysiology of AD. Considerable progress has been made toward the development of disease-modifying treatments. Treatments currently under development mainly target the production, aggregation, and removal of existing amyloid beta-peptide aggregates which are believed to instigate the overall development of the neuropathology. Additional strategies that target tau pathology are being studied to promote neural protection against AD pathology. The current research has continued to expand our knowledge toward the development of disease modifying Alzheimer's therapies; however, no specific treatment strategy capable of demonstrating empirical efficacy and safety has yet to emerge.

PET imaging of the in vivo brain acetylcholinesterase activity and nicotine binding in galantamine-treated patients with AD

The effect of galantamine treatment on cortical acetylcholinesterase (AChE) activity and nicotinic receptor binding was investigated by positron emission tomography (PET) in 18 patients with mild Alzheimer's disease (AD) in relation to galantamine concentration and the patients' cognitive performances. The first 3 months of the study was of a randomized double-blind placebo-controlled design, during which 12 patients received galantamine (16-24mg/day) and 6 patients the placebo, and this was followed by 9 months' galantamine treatment in all patients. The patients underwent PET examinations to measure cortical AChE activity ((11)C-PMP) and (11)C-nicotine binding. Neuropsychological tests were performed throughout the study. Inhibition (30-40%) of cortical AChE activity was observed after 3 weeks to 12 months of galantamine treatment. No significant change in mean cortical (11)C-nicotine binding was observed during the study. (11)C-Nicotine binding, however, positively correlated with plasma galantamine concentration. Both the changes of AChE activity and (11)C-nicotine binding correlated positively with the results of a cognitive test of attention. In conclusion, galantamine caused sustained AChE inhibition for up to 12 months. At the individual level, the in vivo cortical AChE inhibition and (11)C-nicotine binding were associated with changes in the attention domain of cognition rather than episodic memory.

Rivastigmine effects on EEG spectra and three-dimensional LORETA functional imaging in Alzheimer's disease

OBJECTIVE

The objective of the study is to investigate the electrocortical and the global cognitive effects of 3 months rivastigmine medication in a group of mild to moderate Alzheimer's disease patients.

MATERIALS AND METHODS

Multichannel EEG and cognitive performances measured with the Mini Mental State Examination in a group of 16 patients with mild to moderate Alzheimer's Disease were collected before and 3 months after the onset of rivastigmine medication.

RESULTS

Spectral analysis of the EEG data showed a significant power decrease in the delta and theta frequency bands during rivastigmine medication, i.e., a shift of the power spectrum towards 'normalization'. Three-dimensional low resolution electromagnetic tomography (LORETA) functional imaging localized rivastigmine effects in a network that includes left fronto-parietal regions, posterior cingulate cortex, bilateral parahippocampal regions, and the hippocampus. Moreover, a correlation analysis between differences in the cognitive performances during the two recordings and LORETA-computed intracortical activity showed, in the alpha1 frequency band, better cognitive performance with increased cortical activity in the left insula.

CONCLUSION

The results point to a 'normalization' of the EEG power spectrum due to medication, and the intracortical localization of these effects showed an increase of cortical activity in frontal, parietal, and temporal regions that are well-known to be affected in Alzheimer's disease. The topographic convergence of the present results with the memory network proposed by Vincent et al. (J. Neurophysiol. 96:3517-3531, 2006) leads to the speculation that in our group of patients, rivastigmine specifically activates brain regions that are involved in memory functions, notably a key symptom in this degenerative disease.

Potent beta-amyloid modulators

Currently, the potential to interfere with the pathology of beta-amyloid targeting a well-known drugable enzyme, the acetylcholinesterase (AChE), is opened. Peripheral or dual binding site inhibitors of AChE may simultaneously alleviate the cognitive and behavioral deficits in Alzheimer's disease (AD) patients and, more importantly, act as disease-modifying agents delaying amyloid plaque formation. As part of a rational drug design program directed to find dual binding site AChE inhibitors, several families of compounds have been synthesized as potent AChE inhibitors. From these series, several drug candidates were selected based on their potent and selective inhibition of AChE (subnanomolar activity) and their interference with the beta-amyloid aggregation in vitro (IC(50) in the low micromolar range). First in vivo data confirm our initial hypothesis. Oral treatment with NP-61 for 3 months is able to reverse the cognitive impairment (Morris water maze test) and to reduce plaque load in the brains of human amyloid precursor protein transgenic mice (Swedish mutation). These results suggest that NP-61, a potent beta-amyloid modulator, is able to reverse the AD-like neurodegenerative phenotype in transgenic mice, indicating a promising disease-modifying agent for clinical application.

Is long-term treatment of Alzheimer's disease with cholinesterase inhibitor therapy justified?

The cholinesterase inhibitors (ChEIs) donepezil, rivastigmine and galantamine are the current mainstays in the drug treatment of Alzheimer's disease (AD). There is convincing evidence that these agents provide at least modest cognitive, behavioural and functional benefit for 6-12 months at all stages of the disease. Longer term benefits cannot be directly examined by placebo-controlled trials. Nevertheless, the results of virtually all open-label extensions of the pivotal trials, studies of patients with AD at different levels of severity and clinical trials using other designs favour treatment over no treatment for periods of up to 5 years. There are plausible biological reasons why ChEIs might be expected to work over a prolonged period of time although, to date, studies using various markers to chart the effects of medication on long-term disease progression have yielded mixed results. The most contentious issue regarding long-term treatment is economic, but the majority of available economic analyses suggest net savings over the long term if patients with AD receive persistent treatment with ChEIs.

Rivastigmine in the treatment of Alzheimer's disease: an update

Alzheimer's disease is the most common form of dementia in industrialized countries. In the European Union, about 54% of dementia cases are believed to be due to Alzheimer's disease. The condition is an age-related neurodegenerative disorder characterized by multiple cognitive deficiencies, including loss of memory, judgment, and comprehension. These manifestations are accompanied by behavioral and mood disturbances. Although no cure has yet been discovered for Alzheimer's disease, symptomatic therapies are now widely available and offer significant relief to patients and benefits to caregivers in terms of reduced care burden. At the start of the 21st century, health technology assessments recommended three agents for the symptomatic treatment of mild to moderate Alzheimer disease: rivastigmine, donepezil, and galantamine. Rivastigmine (Exelon, Novartis Basel-Switzerland) is a slowly reversible inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), while donepezil (Aricept, Pfizer, New York, USA) and galantamine (Reminyl, Janssen, New Jersey, USA) show no functional inhibition of BuChE, and are considered AChE-selective, rapidly-reversible inhibitors. The efficacy of all three agents has been evaluated in large, double-blind, placebo-controlled clinical trials of up to 6 months' duration. Rivastigmine treatment in mild to moderate Alzheimer's disease improves cognition, activities of daily living, and global function.

Changes in brain 11C-nicotine binding sites in patients with mild Alzheimer's disease following rivastigmine treatment as assessed by PET

RATIONALE

Marked reduction in the cortical nicotinic acetylcholine receptors is observed in the brain of patients suffering from Alzheimer's disease (AD). Although cholinesterase inhibitors are used for symptomatic treatment of mild to moderate AD patients, numerous long-term treatment studies indicate that they might stabilize or halt the progression of the disease by restoring the central cholinergic neurotransmission. Thus, we used positron emission tomography (PET) technique as a sensitive approach to assess longitudinal changes in the nicotine binding sites in the brains of patients with AD.

OBJECTIVE

To evaluate changes in brain nicotinic binding sites in relation to inhibition level of cholinesterases in cerebrospinal fluid (CSF) and plasma and changes in cognitive performance of the patients in different neuropsychological tests after rivastigmine treatment.

MATERIALS AND METHODS

Ten mild AD patients received rivastigmine for 12 months. A dual-tracer PET model with administration of (15)O-water and (S)(-)(11)C-nicotine was used to assess (11)C-nicotine binding sites in the brain at baseline and after 3 and 12 months of the treatment. Cholinesterase activities in CSF and plasma were assessed colorimetrically.

RESULTS

The (11)C-nicotine binding sites were significantly increased 12-19% in several cortical brain regions after 3 months compared with baseline, while the increase was not significant after 12 months of the treatment. After 3 months treatment, low enzyme inhibition in CSF and plasma was correlated with higher cortical (11)C-nicotine binding. The (11)C-nicotine binding positively correlated with attentional task at the 12-month follow-up.

CONCLUSION

Changes in the (11)C-nicotine binding during rivastigmine treatment might represent remodeling of the cholinergic and related neuronal network.

Treatment of attention deficits in neurological disorders

PURPOSE OF REVIEW

Recent work has revealed the impact of deficits of attention on patients with neurological disorders. Here we discuss therapeutic interventions that have been used across a range of conditions, highlighting common themes both in the nature of the attention deficits and the strategies employed to treat them.

RECENT FINDINGS

Cholinesterase inhibitors improve attention, as well as memory, in several conditions including cortical Lewy body disease, Parkinson's disease dementia, traumatic brain injury and Alzheimer's disease. Recent studies suggest that cholinergic stimulation may boost attention further if more specific nicotinic cholinergic agonists are used, or if cholinesterase inhibitors are combined with other agents. Monoaminergic drugs have been shown to improve attention in traumatic brain injury, attention-deficit hyperactivity disorder and hemispatial neglect following right-hemisphere stroke. New compounds targeting other neurotransmitter systems are currently being tested, while several types of behavioural intervention have shown promise, particularly in stroke patients.

SUMMARY

Pharmacological and behavioural interventions can improve attention in neurological patients. In the future, optimum therapy may depend on careful delineation of the components of attention that are impaired as well as assessment of the potential for surviving brain regions to compensate for attention deficits.

Inhibition of acetylcholinesterase in CSF versus brain assessed by 11C-PMP PET in AD patients treated with galantamine

The relationship between acetylcholinesterase (AChE) activity in the CSF and brain of patients with Alzheimer's disease (AD) was investigated in 18 mild AD patients following galantamine treatment. The first 3 months of the study had a randomized double-blind placebo-controlled design, during which 12 patients received galantamine (16-24 mg/day) and six patients placebo. This was followed by 9 months galantamine treatment in all patients. Activities and protein levels of both the "read-through" AChE (AChE-R) and the synaptic (AChE-S) variants in CSF were assessed in parallel together with the regional brain AChE activity by (11)C-PMP and PET. The AChE-S inhibition was 30-36% in CSF, which correlated well with the in vivo AChE inhibition in the brain. No significant AChE inhibition was observed in the placebo group. The increased level of the AChE-R protein was 16% higher than that of AChE-S. Both the AChE inhibition and the increased level of AChE-R protein positively correlated with the patient's performance in cognitive tests associated with visuospatial ability and attention. In conclusion, AChE levels in CSF closely mirror in vivo brain AChE levels prior to and after treatment with the cholinesterase inhibitors. A positive cognitive response seems to dependent on the AChE inhibition level, which is balanced by an increased protein level of the AChE-R variant in the patients.

Relationship Between the Efficacy of Rivastigmine and Apolipoprotein E (ε4) in Patients With Mild to Moderately Severe Alzheimer Disease

Alzheimer disease is the most common form of dementia in Western countries and the leading cause of disability in the over-65 population. Apolipoprotein E (APOE) is a multifunctional protein implied in lipid metabolism and neurobiology. Polymorphisms of the APOE gene have been associated with a variety of medical disorders, from arteriosclerosis to AD. A high frequency of the APOE epsilon4 allele has been found in patients with AD and they seem to have a higher risk of developing the disease. Various authors have suggested a possible relationship between the efficacy of cholinesterase inhibitors and the presence of the APOE epsilon4 allele. The purpose of the present study was to compare prospectively the efficacy of rivastigmine in patients with mild to moderately severe AD presenting different polymorphisms of the APOE gene on chromosome 19 and to determine if there was a difference in the response to rivastigmine treatment in AD patients with the APOE epsilon4 allele (heterozygous or homozygous) versus patients who had other forms of APOE, such as epsilon2 and epsilon3. This was an open-label, nonrandomized, multicenter study in patients over 50 years of age diagnosed with mild to moderately severe AD. The results of the analysis of this study indicate that the presence of at least one APOE epsilon4 allele does not determine a difference in the response to treatment with rivastigmine. The data indicate that knowledge of the patient's genotype is not necessary for treatment with rivastigmine. It would be interesting in the future to analyze the interaction between these 2 factors using other available anticholinesterase drugs.

What Constitutes Clinical Evidence for Neuroprotection in Alzheimer Disease

The progression of Alzheimer disease (AD) corresponds to a prolonged course of neuronal loss in the cerebral cortex. Strategies aimed at reducing the rates of neuronal loss are therefore particularly important. The clinical measures to evaluate the disease-modifying effect of an intervention are readily confounded by any symptomatic benefit of the intervention. Thus, when testing putative neuroprotective agents that are known to have symptomatic effects, it can be difficult to separate the 2 effects. The hypothesis that cholinesterase inhibitors (ChEIs) only treat symptoms caused by cholinergic imbalances in AD is overly simplistic. Evidence has now accumulated that ChEIs have a neuroprotective, disease-modifying property. In this paper, to answer the question of what constitutes clinical evidence for neuroprotection in AD, we have reviewed clinical studies with specific designs, including "delaying end point," "withdrawal," and "randomized start" designs. We have also reviewed data on surrogate biomarkers of disease progression that may indicate a disease-modifying action. In addition, we have reviewed evidence indicating that ChEIs may protect cells in the brain of patients with AD. Among the clinical data suggesting a possible neuroprotective effect of ChEIs, the most rigorous published evidence comes from magnetic resonance imaging (MRI) hippocampal volumetric studies with donepezil.

Apolipoprotein E epsilon4 allele differentiates the clinical response to donepezil in Alzheimer's disease

The existence of an association between apolipoprotein E (APOE) and Alzheimer's disease (AD) has been reported in several studies. The possession of an ApoE epsilon4 allele is now considered a genetic risk factor for sporadic AD. There has been a growing agreement about the role exerted by the ApoE epsilon4 allele on the neuropsychological profile and the rate of cognitive decline in AD patients. However, a more controversial issue remains about a possible influence of the APOE genotype on acetylcholinesterase inhibitor therapy response in AD patients. In order to address this issue, 81 patients diagnosed as having probable AD were evaluated by a complete neuropsychological test battery at the time of diagnosis (baseline) and after 12-16 months (retest). Patients were divided into two subgroups: (1) treated with donepezil at a dose of 5 mg once a day (n = 41) and (2) untreated (n = 40). Donepezil therapy was started after baseline evaluation. The APOE genotype was determined according to standardized procedures. We evaluated the possible effect of the APOE genotype on the neuropsychological tasks in relation to donepezil therapy. The statistical analysis of the results showed a global worsening of cognitive performances for all AD patients at the retest. Differences in the clinical outcome were analysed in the four subgroups of AD patients for each neuropsychological task. ApoE epsilon4 carriers/treated patients had improved or unchanged scores at retest evaluation for the following tasks: visual and verbal memory, visual attention and inductive reasoning and Mini Mental State Examination. These results indicate an effect of donepezil on specific cognitive domains (attention and memory) in the ApoE epsilon4 carriers with AD. This might suggest an early identification of AD patients carrying at least one epsilon4 allele as responders to donepezil therapy.

Longitudinal PET evaluation of cerebral glucose metabolism in rivastigmine treated patients with mild Alzheimer’s disease

In this study 11 patients with mild Alzheimer's disease (AD) were treated with the cholinesterase inhibitor rivastigmine (mean dose 8.6 +/- 1.3'mg) for 12 months and underwent positron emission tomography (PET) studies of cerebral glucose metabolism (CMRglc) and neuropsychological testing at baseline and after 12 months. An untreated group of 10 AD patients served as control group. While the untreated AD patients showed a significant decline of CMRglc in the temporo-parietal and frontal cortical regions after 12 months follow-up the rivastigmine-treated patients showed no decline in CMRglc in corresponding cortical brain regions. Furthermore, a significant dose-related increase in CMRglc was recorded in the right frontal association region after 12 months rivastigmine treatment. A positive correlation was observed between changes in CMRglc and several cognitive tests in patients receiving higher doses (10.5-12'mg) of rivastigmine. These results suggest a stabilization effect of rivastigmine on CMRglc in mild AD patients receiving long-term rivastigmine treatment.

Analysis of association between butyrylcholinesterase K variant and apolipoprotein E genotypes in Alzheimer's disease

Recent studies indicate that there is a synergic association between butyrylcholinesterase-K variant (BChE-K) and apolipoproteinE-epsilon 4 (ApoE-epsilon 4) to promote risk for Alzheimer's disease (AD). Most subsequently replicative studies have been unable to confirm these finding. We attempted to replicate this finding in 105 AD cases and age and sex matched 129 controls from Tehran population, Iran. The BChE genotype of patients were found to be significantly different from controls (chi(2) = 12.2, d.f. = 2, p = 0.002). The frequency of BChE-K allele was also found to differ significantly in cases compared to controls [24% versus 12% (chi(2) = 20.6, d.f. = 2, p < 0.001)] leading to an increased risk of AD in subjects with this allele (OR = 2.5, 95% CI = 1.64-3.8, p = 0.001). This risk was found to increase from (OR = 2.37, 95% CI = 1.3-4.2, p = 0.006) in subjects less than 75 years old to (OR = 3.16, 95% CI = 1.41-7.1, p = 0.001) in subjects 75 years and older. But, the ApoE-epsilon 4 allele association risk was found to decrease from (OR = 9.5, 95% CI = 3.74-24.1, p = 0.001) in subjects <75 years to (OR = 1.36, 95% CI = 0.49-4.1, p = 0.58) in those subjects 75 years and older. Furthermore, we found a very strong synergic association between BChE-K and ApoE-epsilon 4 OR = 19.1 (95% CI = 428-85.45, p < 0.001). In spite of this, synergism decreased from OR = 36.2 (95% CI = 4.4-296, p = 0.001) in subjects <75 year olds to OR = 6.2 (95% CI = 0.9-72.4, p = 0.06) in subjects > or =75 years. We have found that BChE-K and ApoE-epsilon 4 alleles act synergistically to increase the risk of the late-onset AD, particularly in age group <75 years in Tehran, Iran.

Rivastigmine for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the most common cause of dementia in the elderly. One of the most successful therapeutic strategies for Alzheimer's disease has been the use of acetylcholinesterase inhibitors to enhance surviving cholinergic neurotransmission by inhibiting breakdown of released acetylcholine. The first generation acetylcholinesterase inhibitors, such as tacrine, revealed major limitations to use including hepatotoxicity. Several second generation acetylcholinesterase inhibitors have now been introduced, including rivastigmine, which are believed to have superior proprieties. The mode of action and metabolism of rivastigmine suggest that it is unlikely to interact significantly with other medications. This is of particular relevance in elderly AD patients, the majority of whom are likely to be receiving concomitant medication. Large multi-centre trials have been completed in the USA, Canada, Europe and South Africa. Rivastigmine has received EU approval for use in all member states. It has approval in 30 countries but not the US. It is currently under review by the Food and Drug Administration, who requested additional analyses in 1998.

OBJECTIVES

To determine the clinical efficacy and safety of rivastigmine for patients with dementia of the Alzheimer's type.

SEARCH STRATEGY

The Cochrane Controlled Trials Register, the Dementia Group Register of Clinical Trials, other electronic databases and other sources of reports were searched using the terms ENA 713, EXELON, and rivastigmine in addition to the terms for controlled trials in dementia (see the Group's search strategy for full details).

SELECTION CRITERIA

All unconfounded, double-blind, randomised trials in which treatment with rivastigmine was administered for more than one day and compared to placebo for patients with dementia of the Alzheimer's type.

DATA COLLECTION AND ANALYSIS

Data were extracted by the reviewer (JSB) and entered into an appropriate meta-analysis. The data extracted were cross-checked by the second reviewer (VI). For each outcome measure, data were sought on every patient randomised. To allow an intention-to-treat analysis, the data were sought irrespective of compliance, whether or not the patient was subsequently deemed ineligible, or otherwise excluded from treatment or follow-up. If these data were not available, an analysis of data on patients who completed treatment was conducted.

MAIN RESULTS

There are seven included trials. There are no published reports for two large phase III trials, B304 and B351, although they were completed more than 3 years ago. These are part of the Novartis ADENA programme and comprise 1379 (49%) out of 2803 phase III patients. It is unclear how missing data are replaced in ITT analyses, as reports from the ADENA programme provide no description of the use of this method. This has a profound effect on the results: if the method is substantially the same as LOCF, the benefits of treatment inferred from the analyses described in the publications as ITT, may be exaggerated. The meta-analysis reveals benefits on cognitive function as measured by ADAS-Cog test scores for the higher dose of rivastigmine compared to placebo at 26 weeks and for the lower dose. An additional analysis of ADAS-Cog dichotomised into those showing less than 4 points improvement and those showing 4 or more points improvement at 26 weeks shows benefit for cognitive function for the higher dose of rivastigmine compared to placebo and not for the lower dose. Global clinical state, dichotomised, counting those showing no change or decline, against those showing improvement shows benefit due to lower dose rivastigmine compared to placebo at 26 weeks and not for the higher dose. One trial reported results at 18 weeks and there are no significant differences between higher dose rivastigmine and placebo. One trial reported results at 13 weeks, and there are no significant differences between the 4 or 6 mg/d rivastigmine group and p