Memantine treatment in patients with moderate to severe Alzheimer disease already receiving donepezil: a randomized controlled trial

Alzheimer Disease and Its Management

Alzheimer disease is a progressive degenerative disorder of the brain characterized by a slow, progressive decline in cognitive function and behavior. As the disease advances, persons with Alzheimer disease have tough time with daily usage of things like using the phone, cooking, handling money, or driving the car. The disease is more common in elder population. It is estimated that Alzheimer disease affects 15 million people worldwide and approximately 4 million Americans. The clinical features of Alzheimer disease overlaps with common signs of aging, and other types of dementia, hence the diagnosis remains difficult. The neuropathologic hallmarks of the disorder are amyloid-rich senile plaques, neurofibrillary tangles, and neuronal degeneration. Drugs approved for treating Alzheimer disease include acetylcholinesterase inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonist. Caregivers not getting adequate information about Alzheimer disease may believe that nothing can be done to manage its symptoms. Understanding the extent of Alzheimer disease related knowledge can assist disease management that result in improved disease management and reduced care costs. This article attempts to focus on some of the important recent developments in understanding and management of Alzheimer disease.

Clinical practice with anti-dementia drugs: a consensus statement from British Association for Psychopharmacology

The British Association for Psychopharmacology (BAP) coordinated a meeting of experts to review the evidence on the drug treatment for dementia. The level of evidence (types) was rated using a standard system: Types 1a and 1b (evidence from meta-analysis of randomised controlled trials or at least one controlled trial respectively); types 2a and 2b (one well-designed study or one other type of quasi experimental study respectively); type 3 (non-experimental descriptive studies); and type 4 (expert opinion). There is type 1a evidence for cholinesterase inhibitors (donepezil, rivastigmine and galantamine) for mild to moderate Alzheimer's disease; memantine for moderate to severe Alzheimer's disease; and for the use of bright light therapy and aromatherapy. There is type 1a evidence of no effect of anti inflammatory drugs or statins. There is conflicting evidence regarding oestrogens, with type 2a evidence of a protective effect of oestrogens but 1b evidence of a harmful effect. Type 1a evidence for any effect of B12 and folate will be forthcoming when current trials report. There is type 1b evidence for gingko biloba in producing a modest benefit of cognitive function; cholinesterase inhibitors for the treatment of people with Lewy body disease (particularly neuropsychiatric symptoms); cholinesterase inhibitors and memantine in treatment cognitive impairment associated with vascular dementia; and the effect of metal collating agents (although these should not be prescribed until more data on safety and efficacy are available). There is type 1b evidence to show that neither cholinesterase inhibitors nor vitamin E reduce the risk of developing Alzheimer's disease in people with mild cognitive impairment; and there is no evidence that there is any intervention that can prevent the onset of dementia. There is type 1b evidence for the beneficial effects of adding memantine to cholinesterase inhibitors, and type 2b evidence of positive switching outcomes from one cholinesterase inhibitor to another. There is type 2a evidence for a positive effect of reminiscence therapy, and type 2a evidence that cognitive training does not work. There is type 3 evidence to support the use of psychological interventions in dementia. There is type 2 evidence that a clinical diagnosis of dementia can be made accurately and that brain imaging increases that accuracy. Although the consensus statement dealt largely with medication, the role of dementia care in secondary services (geriatric medicine and old age psychiatry) and primary care, along with health economics, was discussed. There is ample evidence that there are effective treatments for people with dementia, and Alzheimer's disease in particular. Patients, their carers, and clinicians deserve to be optimistic in a field which often attracts therapeutic nihilism.

Pharmacological treatment of non-Alzheimer dementias

PURPOSE OF REVIEW

One hundred years after the first description by Alois Alzheimer and with the advent of first pharmacological treatments, most researchers concentrate on Alzheimer's disease. Millions of patients, however, suffer from other dementias and search for help beyond diagnosis.

RECENT FINDINGS

New clinical data concerning the treatment of non-Alzheimer dementias mainly relate to the clinical use of antidementiva that is already approved for the treatment of Alzheimer's disease. Few studies test new pharmacological paradigmata. For some forms like vascular dementias, the possibility of prevention is the most valuable approach that should be enforced more aggressively. For other savaging dementias new unconventional treatment trials should be encouraged.

SUMMARY

Research for non-Alzheimer dementias lags behind those for the Alzheimer field. For many patients, we still have nothing but words. At the same time, probably with regard to cost constraints, some acteurs like health insurances and legislators are inclined to nurture therapeutic nihilism and cultivate ethical qualms and demurs instead of supporting clinical trials or at least not blocking them with bureaucratic hand-cuffs, whereas pharmaceutical companies contemplate naturally over questions like return of investment. The clinical researchers should fight this fatigue and look for ways out of this quagmire for our patients.

Cognitive Response to Memantine in Moderate to Severe Alzheimer Disease Patients Already Receiving Donepezil

OBJECTIVE

To investigate the cognitive effects of the N-methyl-D-aspartate receptor antagonist, memantine, with a post-hoc exploratory reanalysis of a 24-week randomized, double-blind, placebo-controlled, parallel group clinical trial comparing memantine (20 mg per day) to placebo in patients with moderate to severe Alzheimer disease (AD) receiving treatment with the cholinesterase inhibitor, donepezil.

METHODS

The effects of memantine on individual items of the Severe Impairment Battery (SIB), subscale performance, and 3 post-hoc-derived aggregate subscales were investigated. Analyses were based on the intention-to-treat population using last observation carried forward and observed cases approaches. The SIB components were assessed at baseline, weeks 4, 8, 12, 18, and 24.

RESULTS

The mean change from baseline by visit and at study end point on the SIB showed statistically significant differences between the memantine and placebo groups at all visits beginning at week 8 (last observation carried forward and observed cases). The SIB subscale analysis showed statistically significantly greater effects of memantine than placebo on memory, language, and praxis. When the SIB domains were aggregated using a face valid approach to create 3 higher-order subscales, memantine treatment resulted in statistically significant differences on memory, language, and praxis compared with placebo.

CONCLUSIONS

These post-hoc analyses support the beneficial effects of memantine on cognition observed in a previously reported clinical trial. The results presented here suggest an effect of memantine on memory, language, and praxis in patients with moderate to severe AD and support the efficacy of memantine for the treatment of cognitive deficits in AD.

A randomised pilot study to assess the efficacy of an interactive, multimedia tool of cognitive stimulation in Alzheimer's disease

OBJECTIVE

To determine the usefulness of an interactive multimedia internet-based system (IMIS) for the cognitive stimulation of Alzheimer's disease.

METHODS

This is a 24-week, single-blind, randomised pilot study conducted on 46 mildly impaired patients suspected of having Alzheimer's disease receiving stable treatment with cholinesterase inhibitors (ChEIs). The patients were divided into three groups: (1) those who received 3 weekly, 20-min sessions of IMIS in addition to 8 h/day of an integrated psychostimulation program (IPP); (2) those who received only IPP sessions; and (3) those who received only ChEI treatment. The primary outcome measure was the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog). Secondary outcome measures were: Mini-Mental State Examination (MMSE), Syndrom Kurztest, Boston Naming Test, Verbal Fluency, and the Rivermead Behavioral Memory Test story recall subtest.

RESULTS

After 12 weeks, the patients treated with both IMIS and IPP had improved outcome scores on the ADAS-Cog and MMSE, which was maintained through 24 weeks of follow-up. The patients treated with IPP alone had better outcome than those treated with ChEIs alone, but the effects were attenuated after 24 weeks. All patients had improved scores in all of the IMIS individual tasks, attaining higher levels of difficulty in all cases.

CONCLUSION

Although both the IPP and IMIS improved cognition in patients with Alzheimer's disease, the IMIS program provided an improvement above and beyond that seen with IPP alone, which lasted for 24 weeks.

Neuropsychiatric Inventory Workshop: Behavioral and Psychologic Symptoms of Dementia in Asia

The Neuropsychiatric Inventory (NPI) was introduced in 1994 and has since become a standard instrument for clinical trials and other types of behavioral research in dementing disorders. Its reliability and validity have been confirmed. The NPI was the subject of a workshop in Asia in conjunction with the International Workgroup on Dementia Drug Guidelines (IWG). Investigators using the NPI from 4 Asian areas--Taiwan, Hong Kong, Japan, Thailand--presented conclusions from their research. A high prevalence of behavioral disturbances across Asian countries was found and the rates are similar to those observed in Western countries. Apathy is more difficult to detect and characterize in Asian populations. Neurobiologic studies show an excess of some serotonin receptor gene polymorphisms in patients without behavioral disturbances and positron emission tomography reveals reductions in frontal lobe metabolism in patients manifesting depression as measured by the NPI. Studies in Thailand show relationships among verbal fluency, activities of daily living, and neuropsychiatric symptoms particularly agitation, apathy, and disinhibition. This suggests a triad of symptoms of behavioral abnormalities, executive dysfunction, and abnormalities of activities of daily living that impugn frontal lobe function. The NPI is a reliable and useful instrument to characterize behavioral changes in Asian and Western populations.

In vitro galantamine-memantine co-application: mechanism of beneficial action

Several drugs are in clinical use for symptomatic treatment of Alzheimer's disease patients. Since Alzheimer's disease is known to be associated with down-regulation of the cholinergic and N-methyl-D-aspartate (NMDA) systems, most of these drugs inhibit acetylcholinesterase, potentiate the activity of nicotinic acetylcholine receptors (nAChRs), or modulate NMDA receptors. Galantamine is an anticholinesterase and allosterically potentiates the activity of the nicotinic receptors. We have recently found that galantamine potentiates the activity of NMDA receptors as well. Memantine is unique in that it inhibits the NMDA receptors. We have developed a hypothesis that combining galantamine and memantine will be more effective for improving the patient's conditions than monotherapy with either drug. Patch clamp and intracellular Ca(2+) imaging experiments using rat cortical and hippocampal neurons clearly provided the in vitro bases for our hypothesis. Memantine blocked the extrasynaptic NMDA receptor 100 times more potently than the synaptic NMDA receptor at negative membrane potentials and the block of both types of NMDA receptors was attenuated with depolarization. However, galantamine potentiation of the NMDA receptors was not voltage dependent. Thus, co-application of memantine with galantamine prevented the galantamine potentiation and the activation of extrasynaptic NMDA receptors, but membrane depolarization revealed the galantamine potentiation. Therefore, cell death is expected to be prevented by memantine near the resting potential while the NMDA-mediated synaptic transmission, which is down-regulated in the patients, is maintained and potentiated by galantamine. These results provide in vitro bases for the beneficial actions of galantamine and memantine combinations.

Cognitive impairment

As populations continue to age, the prevalence of dementia is expected to increase. AD is by far the most common cause of dementia. The clinical course of dementia represents the challenges that this disease presents. There are no truly effective therapies for treating dementia, and the cost effectiveness of ChEIs has been challenged; however, there has been an explosion of information about AD. Evidence-based practice parameters for diagnosis and management of dementia have been developed. There has been an increased interest in the possible prodromal states of dementia, such as MCI. The concept of MCI has risen in prominence in recent years; it is speculated that initiation of therapies early in the course of disease may be needed for them to be effective. Considering the enormous burdens that AD places on individuals and society, disease-modifying treatments for AD are needed desperately. There are promising avenues for the development of potentially disease-modifying therapies for this devastating disease.

Early diagnostics and therapeutics for Alzheimer's disease--how early can we get there?

Alzheimer's disease (AD) is a major threat for the rapidly aging world population. AD is the leading cause of dementia and a major cause of death in developed countries. The disease puts a tremendous practical, emotional and financial burden on individuals and governments. Clinicians and researchers in the AD field face great challenges: the pathophysiological processes that cause AD are not well understood, definite diagnosis of AD requires autopsy, and therapeutic options are limited to treating the symptoms rather than the cause of the disease. Nevertheless, new insights into the earliest events that lead to development of AD increase hope that reliable diagnostics and efficacious therapies may emerge.

The chemical biology of clinically tolerated NMDA receptor antagonists

Most neuroprotective drugs have failed in clinical trials because of side-effects, causing normal brain function to become compromised. A case in point concerns antagonists of the N-methyl-D-aspartate type of glutamate receptor (NMDAR). Glutamate receptors are essential to the normal function of the central nervous system. However, their excessive activation by excitatory amino acids, such as glutamate itself, is thought to contribute to neuronal damage in many neurological disorders ranging from acute hypoxic-ischemic brain injury to chronic neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. The dual role of NMDARs in particular for normal and abnormal functioning of the nervous system imposes important constraints on possible therapeutic strategies aimed at ameliorating neurological diseases. Blockade of excessive NMDAR activity must therefore be achieved without interference with its normal function. In general, NMDAR antagonists can be categorized pharmacologically according to the site of action on the receptor-channel complex. These include drugs acting at the agonist (NMDA) or co-agonist (glycine) sites, channel pore, and modulatory sites, such as the S-nitrosylation site where nitric oxide (NO) reacts with critical cysteine thiol groups. Because glutamate is thought to be the major excitatory transmitter in the brain, generalized inhibition of a glutamate receptor subtype like the NMDAR causes side-effects that clearly limit the potential for clinical applications. Both competitive NMDA and glycine antagonists, even although effective in preventing glutamate-mediated neurotoxicity, will cause generalized inhibition of NMDAR activities and thus have failed in many clinical trials. Open-channel block with the property of uncompetitive antagonism is the most appealing strategy for therapeutic intervention during excessive NMDAR activation as this action of blockade requires prior activation of the receptor. This property, in theory, leads to a higher degree of channel blockade in the presence of excessive levels of glutamate and little blockade at relatively lower levels, for example, during physiological neurotransmission. Utilizing this molecular strategy of action, we review here the logical process that we applied over the past decade to help develop memantine as the first clinically tolerated yet effective agent against NMDAR-mediated neurotoxicity. Phase 3 (final) clinical trials have shown that memantine is effective in treating moderate-to-severe Alzheimer's disease while being well tolerated. Memantine is also currently in trials for additional neurological disorders, including other forms of dementia, glaucoma, and severe neuropathic pain. Additionally, taking advantage of memantine's preferential binding to open channels and the fact that excessive NMDAR activity can be down-regulated by S-nitrosylation, we have recently developed combinatorial drugs called NitroMemantines. These drugs use memantine as a homing signal to target NO to hyperactivated NMDARs in order to avoid systemic side-effects of NO such as hypotension (low blood pressure). These second-generation memantine derivatives are designed as pathologically activated therapeutics, and in preliminary studies appear to have even greater neuroprotective properties than memantine.

Memantine treatment in mild to moderate Alzheimer disease: a 24-week randomized, controlled trial

OBJECTIVE

The objective of this study was to compare the efficacy and safety of the moderate-affinity, uncompetitive N-methyl-d-aspartate receptor antagonist, memantine, versus placebo in patients with mild to moderate Alzheimer disease (AD).

METHOD

This was a randomized, double-blind, placebo-controlled clinical trial conducted at 42 U.S. sites. Participants were 403 outpatients with mild to moderate AD and Mini-Mental State Examination scores of 10-22 randomized to memantine (20 mg/day; N=201) or placebo (N=202) for 24 weeks. Primary outcomes were change from baseline at 24 weeks on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog), a measure of cognition, and on the Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus), a global measure. Secondary outcomes included change on the Neuropsychiatric Inventory (NPI) and the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory (ADCS-ADL(23)), measures of behavior and function, respectively.

RESULTS

Most (82.4%) participants completed the trial. Memantine resulted in significantly better outcomes than placebo on measures of cognition, global status, and behavior when based on the protocol-specified primary last observation carried forward imputation as well as a mixed-models repeated-measures approach applied to the continuous outcomes. Treatment discontinuations because of adverse events for memantine versus placebo were 19 (9.5%) and 10 (5.0%), respectively.

CONCLUSIONS

These results support the safety and efficacy of memantine for the treatment of mild to moderate AD.

Alzheimer's disease

Alzheimer's disease is the most common cause of dementia. Research advances have enabled detailed understanding of the molecular pathogenesis of the hallmarks of the disease--ie, plaques, composed of amyloid beta (Abeta), and tangles, composed of hyperphosphorylated tau. However, as our knowledge increases so does our appreciation for the pathogenic complexity of the disorder. Familial Alzheimer's disease is a very rare autosomal dominant disease with early onset, caused by mutations in the amyloid precursor protein and presenilin genes, both linked to Abeta metabolism. By contrast with familial disease, sporadic Alzheimer's disease is very common with more than 15 million people affected worldwide. The cause of the sporadic form of the disease is unknown, probably because the disease is heterogeneous, caused by ageing in concert with a complex interaction of both genetic and environmental risk factors. This seminar reviews the key aspects of the disease, including epidemiology, genetics, pathogenesis, diagnosis, and treatment, as well as recent developments and controversies.

Acceleration of amyloid beta-peptide aggregation by physiological concentrations of calcium

Alzheimer disease is characterized by the accumulation of aggregated amyloid beta-peptide (Abeta) in the brain. The physiological mechanisms and factors that predispose to Abeta aggregation and deposition are not well understood. In this report, we show that calcium can predispose to Abeta aggregation and fibril formation. Calcium increased the aggregation of early forming protofibrillar structures and markedly increased conversion of protofibrils to mature amyloid fibrils. This occurred at levels 20-fold below the calcium concentration in the extracellular space of the brain, the site at which amyloid plaque deposition occurs. In the absence of calcium, protofibrils can remain stable in vitro for several days. Using this approach, we directly compared the neurotoxicity of protofibrils and mature amyloid fibrils and demonstrate that both species are inherently toxic to neurons in culture. Thus, calcium may be an important predisposing factor for Abeta aggregation and toxicity. The high extracellular concentration of calcium in the brain, together with impaired intraneuronal calcium regulation in the aging brain and Alzheimer disease, may play an important role in the onset of amyloid-related pathology.

Effects of memantine and donepezil on amyloid beta-induced memory impairment in a delayed-matching to position task in rats

We investigated the effects of memantine and donepezil on amyloid beta (Abeta)-induced memory impairment in rats, which was assessed by a delayed-matching to position (DMPT) paradigm in three-lever operant chambers. Aggregated Abeta1-40 was microinjected bilaterally (1 nmol/side) into both CA1 and CA3 subfields of the hippocampus in rats that had previously performed the DMTP task. Memantine (20 mg/(kg day), s.c.) was continuously infused by an osmotic minipump for 4 weeks from 3 days before the microinjection of Abeta. Donepezil (2.5 mg/kg, p.o.) was administered 60 min before the DMTP test session. Bilateral microinjections of Abeta1-40 into the hippocampus resulted in a delayed, but persistent impairment of DMTP performance, which appeared more than 50 days after the injection. Memantine prevented the development of Abeta-induced memory impairment, while donepezil symptomatically alleviated the deficits. Because of a ceiling effect, the combination of donepezil with memantine failed to produce any additive or synergic effects. These results support the clinical data showing that memantine and donepezil are effective for the treatment of Alzheimer's disease. Moreover, it is suggested that memantine is effective for preventing Abeta-induced short-term memory impairment.

Effects of donepezil on neuropsychiatric symptoms in patients with dementia and severe behavioral disorders

OBJECTIVE

The objective of this study was to conduct exploratory analyses of data pertaining to the efficacy of donepezil treatment of patients with severe behavioral disturbances. Preliminary studies suggest that cholinesterase inhibitors, including donepezil, may reduce behavioral disturbances in patients with Alzheimer disease (AD). Most patients included in clinical trials have had low levels of psychopathology at baseline, and the effect of cholinesterase inhibitors on patients with more severe behavioral disturbances is unknown. The authors report the effects of donepezil on behavioral disturbances in patients with relatively severe psychopathology at baseline.

METHODS

This is a hypothesis-driven secondary analysis of a three-phase study involving donepezil and sertraline. In phase 1, psychotropic agents were withdrawn; in phase 2, patients were treated in an open-label fashion with donepezil for 8 weeks; and in phase 3, patients on donepezil were randomized to receive placebo or sertraline for an additional 12 weeks. The data set analyzed is comprised of the patient population treated with donepezil (without sertraline) for 20 weeks. One hundred twenty patients were included in the analyses. Mean age was 76 years, average Mini-Mental State Examination Score was 18, and mean Neuropsychiatric Inventory (NPI) total score was 30. Primary efficacy assessments were the NPI, the Clinical Global Impression-Improvement, and the Clinical Global Impression-Severity scales. Secondary measures included the Behavioral Pathology in Alzheimer's Disease Rating Scale, The Hamilton Depression Rating Scale, and the Alzheimer's Disease Functional Assessment and Change Scale.

RESULTS

Excellent concurrent validity was noted between the NPI and the Behavioral Pathology in Alzheimer's Disease Rating Scale. The total score of the NPI was significantly reduced over the 20 weeks of therapy with donepezil. Sixty-two percent of patients had at least a 30% reduction in the total NPI score (significantly greater than the number with no meaningful response). Likewise, more patients had total or partial resolution of depression and delusions than those who had no meaningful change. Factor analysis of baseline NPI data revealed five factors, including a psychosis factor, an agitation factor, mood factor, frontal lobe function factor, and appetite and eating disorders factor. Clinically meaningful treatment effect sizes were notable for the delusion factor (0.340) and the mood factor (0.39). There were significant correlations between the Clinical Global Impression-Improvement and reductions in mood and agitation scores.

CONCLUSION

The results of these analyses suggest that donepezil reduces behavioral symptoms, particularly mood disturbances and delusions, in patients with AD with relatively severe psychopathology.

Memantine combined with an acetyl cholinesterase inhibitor - hope for the future?

BACKGROUND

Memantine and cholinesterase inhibitors (ChEI) have distinct pharmacological actions, and interest in the use of combination therapy for Alzheimer's disease (AD) is increasing.

OBJECTIVE

To assess the available data on the use of memantine-ChEI combination and to develop evidence-based recommendations.

METHOD

A systematic literature review with detailed discussion of the current evidence base.

RESULTS

AVAILABLE DATA ARE LIMITED: five studies of which two were randomized, double-blind, placebo-controlled trials. One study indicated that memantine-ChEI combination is not significantly more effective than placebo-ChEI in mild to moderate AD, but data were published in abstract and poster form only. A second study indicated that the memantine-ChEI combination is significantly more effective than placebo-ChEI in moderate to severe AD. The calculated effect sizes of 0.36 on cognition and 0.12 on function, which were the primary outcomes, were small, indicating a clinically minimal effect on cognition and no effect on function. No data are available on whether combination treatment is more effective than memantine monotherapy.

CONCLUSION

The available data do not justify the use of combination therapy. Future studies should include three arms (memantine-placebo, placebo-ChEI, and memantine-ChEI), be of an adequate size and duration, and use pragmatic measures. Clinicians should have full access to data from any future trials.

Cost-effectiveness of memantine in community-based Alzheimer's disease patients: An adaptation in Spain

Several clinical trials have demonstrated the efficacy and safety of the NMDA antagonist memantine in moderately severe to severe Alzheimer's disease (AD) patients. A 28-week pharmacoeconomic study conducted in the US also showed a reduction of total healthcare costs and informal care compared to placebo. Long-term implications of memantine treatment were modelled in the UK and Finland and revealed reductions in dependency, institutionalization and costs. However, these conclusions were not directly applicable to the Spanish setting where patients are mainly treated within the community. The objective of this study was to estimate the long-term implications in terms of costs and health benefits of memantine therapy compared to standard care using a Spanish adaptation of previous models over a 2-year time horizon. As in previous adaptations, Markov health states were defined as a combination of severity (mild-moderate, moderately severe, severe) and dependency plus death as the absorbing state. Spain-specific data (costs, mortality and epidemiological data) were obtained from local and recently published cohorts of AD patients. Data on the effectiveness of memantine were derived from a randomized double-blind placebo-controlled clinical trial of 252 moderately severe to severe AD patients. Effectiveness was measured as the time spent in a non-dependent health state. The evaluation was conducted over 2 years, while the efficacy of memantine was applied for 1 year only in order to ensure a conservative approach. The robustness of the model was tested by conducting stochastic analyses and various sensitivity analyses on the key assumptions. Patients receiving standard care were estimated to spend 6 months in a non-dependent state and to incur average total costs of Euro 24,700 over 2 years. The memantine strategy was associated with an additional 2.5 months in a non-dependent state and a Euro 700 cost reduction. Monte-Carlo simulations and sensitivity analyses supported these findings. Memantine appears to be cost-effective compared with standard care in moderately severe to severe AD patients in a Spanish setting. The prolonged independence provided by memantine treatment translated into cost reductions which offset drug costs and resulted in overall cost-savings.

Low doses of memantine disrupt memory in adult rats

Memantine, a drug recently approved for treatment of Alzheimer's disease, has been characterized as a unique NMDA antagonist that confers protection against excitotoxic neurodegeneration without the serious side effects that other NMDA antagonists are known to cause. In the present study, we determined what dose of memantine is required to protect the adult rat brain against an NMDA receptor-mediated excitotoxic process and then tested that dose and a range of lower doses to determine whether the drug in this dose range is associated with significant side effects. Consistent with previous research, we found that memantine confers a neuroprotective effect beginning at an intraperitoneal dose of 20 mg/kg, a dose that we found, contrary to previous reports, produces locomotor disturbances severe enough to preclude testing for learning and memory effects. We then determined that, at intraperitoneal doses of 10 and 5 mg/kg, memantine disrupts both memory and locomotor behaviors. Rats treated with these doses performed at control-like levels in learning a hole-board task but were significantly impaired in demonstrating what they had learned when tested 24 h later. This impairment of memory retention was not state dependent in that it was demonstrable regardless of whether the rats were or were not exposed to memantine on the day of retention testing. We conclude that, in the adult rat, memantine behaves like other NMDA antagonists in that it is neuroprotective only at doses that produce intolerable side effects, including memory impairment.

A responder analysis of memantine treatment in patients with Alzheimer disease maintained on donepezil

OBJECTIVE

The objective of this study was to examine the clinical utility of memantine for moderate-to-severe Alzheimer disease (AD) using responder analyses.

METHOD

Data from a previously published 24-week, randomized, double-blind, placebo-controlled trial of 10 mg memantine twice a day in patients with moderate-to-severe AD (N = 404) on stable donepezil therapy were evaluated using three sets of responder criteria. Response rates were calculated and analyzed for the intention-to-treat population using a generalized estimating equations model. The following outcomes were examined separately and in combination: the Alzheimer's Disease Cooperative Study-Activities of Daily Living 19-Item Inventory (ADCS-ADL19), Severe Impairment Battery (SIB), Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus), and Neuropsychiatric Inventory (NPI).

RESULTS

When treatment response required cognitive improvement relative to baseline, memantine yielded higher response rates than placebo. When treatment response was defined as stabilization of individual outcomes, memantine resulted in significantly higher response rates than placebo for all outcomes, with number needed to treat (NNT) ranging from 8-10. More conservative definitions of response that required simultaneous stabilization on multiple outcome measures again favored memantine treatment for six of 10 combinatorial definitions.

CONCLUSIONS

These responder analyses may assist clinicians in evaluating the impact of memantine in a relevant clinical scenario, i.e., in patients with AD previously stabilized on a cholinesterase inhibitor. The current results indicate that in this setting, memantine produces both improvement and stabilization of symptoms, across multiple outcomes, and thus provides a clinically important treatment benefit for patients with moderate-to-severe AD.

Rivastigmine for Alzheimer's disease

Alzheimer's disease is the most common form of neurodegenerative dementia and poses considerable health challenges to both patients and their families. Rivastigmine is a powerful slow-reversible, noncompetitive carbamate cholinesterase inhibitor that is approved for the treatment of mild-to-moderate Alzheimer's disease. Randomized, double-blind, placebo-controlled trials of up to 6 months duration have shown beneficial effects of rivastigmine compared with placebo in measures of cognition and global functioning. Less rigorous but growing data suggest that the beneficial effects may endure for up to 5 years, extend to more advanced stages of Alzheimer's disease and may occur in noncognitive domains, such as activities of daily living and the behavioral symptoms of Alzheimer's disease. Evidence from controlled studies also supports the use of rivastigmine for cognitive and behavioral symptoms in Alzheimer's disease associated with vascular risk factors, dementia with Lewy bodies and Parkinson's disease dementia. Early and continued treatment of Alzheimer's disease with rivastigmine maximizes the observed beneficial effects. The most prominent adverse effect of rivastigmine is centrally mediated cholinergic gastrointestinal events, which can be minimized by slower dose-escalation intervals and administration with a full meal. Therapeutic dosing is 6-12 mg/day given twice daily, with higher doses having the potential for greater benefits.

Cholinergic and glutamatergic drugs in Alzheimer's disease therapy

The pathology and clinical symptoms of Alzheimer's disease are well known and include plaques, tangles, cell loss and dysfunction. The target of current treatments is to improve neuronal dysfunction and produce symptomatic benefits based on a clear understanding of neurotransmitter biochemistry. The purpose of this review is to examine the scientific background to currently available treatments, discuss the clinical experience of employing these drugs in Alzheimer's disease patients and review the socioeconomic influences on their use in the future.

Memantine for dementia

BACKGROUND

Memantine, a low affinity antagonist to glutamate NMDA receptors, may prevent excitatory neurotoxicity in dementia.

OBJECTIVES

To determine efficacy and safety of memantine for people with Alzheimer's disease (AD), vascular (VD) and mixed dementia.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group was searched on 8th February 2006. This register contains references from all major healthcare databases and many ongoing trial databases and is updated regularly. In addition, the search engines Copernic and Google were used to identify unpublished trials through inspection of the websites of licensing bodies like the FDA , EMEA and NICE and of companies' websites (Lundbeck, Merz, Forest, Suntori etc) and clinical trials registries.

SELECTION CRITERIA

Double-blind, parallel group, placebo-controlled, randomized trials of memantine in people with dementia.

DATA COLLECTION AND ANALYSIS

Data were pooled where possible. Intention-to-treat (ITT) and observed case (OC) analyses are reported.

MAIN RESULTS

1. Moderate to severe AD. Two out of three six month studies show a small beneficial effect of memantine. Pooled data indicate a beneficial effect at six months on cognition (2.97 points on the 100 point SIB, 95% CI 1.68 to 4.26, P < 0.00001), activities of daily living (1.27 points on the 54 point ADCS-ADLsev, 95% CI 0.44 to 2.09, P = 0.003) and behaviour (2.76 points on the 144 point NPI, 95% CI 0.88 to 4.63, P=0.004), supported by clinical impression of change (0.28 points on the 7 point CIBIC+, 95% CI 0.15 to 0.41, P < 0.0001).2. Mild to moderate AD. Pooled data from three unpublished studies indicate a marginal beneficial effect at six months on ITT cognition (0.99 points on the 70 point ADAS-Cog, 95% CI 0.21 to 1.78, P = 0.01) which was barely detectable clinically (0.13 CIBIC+ points, 95% CI 0.01 to 0.25, P = 0.03) but no effect on behaviour, activities of daily living or OC analysis of cognition.3. Mild to moderate vascular dementia. Pooled data from two six month studies indicated a small beneficial effect of memantine on cognition (1.85 ADAS-Cog points, 95% CI 0.88 to 2.83, P = 0.0002), and behaviour (0.84 95% CI 0.06 to 0.91, P = 0.03) but this was not supported by clinical global measures.4. Patients taking memantine were slightly less likely to develop agitation (134/1739, 7.7% versus 175/1873, 9.3% OR 0.78, 95% CI 0.61 to 0.99, P = 0.04). This effect was slightly larger, but still small, in moderate to severe AD (58/506 [12%] vs 88/499 [18%]; OR = 0.6, 95% CI 0.42 to 0.86, P = 0.005). There is no evidence either way about whether it has an effect on agitation which is already present.5. Memantine is well tolerated.

AUTHORS' CONCLUSIONS

Memantine has a small beneficial effect at six months in moderate to severe AD. In patients with mild to moderate dementia, the small beneficial effect on cognition was not clinically detectable in those with vascular dementia and was detectable in those with AD. Memantine is well tolerated.

Memantine, an uncompetitive low affinity NMDA open-channel antagonist improves clinical rating scores in a multiple infarct embolic stroke model in rabbits

The blockade of NMDA receptors has been pursued as a strategy to reduce the consequences of acute ischemic stroke (AIS) and NMDA receptors remain a valid therapeutic target to treat AIS. Because the pharmacological and toxicity profile of memantine in Alzheimer's disease patients appears to be good, we determined whether memantine would be effective at improving behavioral performance following embolic strokes in rabbits. For these studies, we used a rabbit multiple infarct ischemia model with a well-defined behavioral endpoint. In this study, memantine dissolved in PBS was given intravenously either as a bolus injection (over 1 min) or infused over 60 min. The P(50) of the control groups measured 24 h after embolization were 1.12 +/- 0.18 mg and 1.08 +/- 0.23 mg for the bolus injected and infused groups, respectively. Bolus injections of memantine at 1 mg/kg and 10 mg/kg were not effective at altering the P(50) value and memantine at a dose of 25 mg/kg was lethal. However, slowly infused memantine (25 mg/kg) significantly increased the P(50) value to 2.31 +/- 0.48 mg and 3.13 +/- 1.13 mg when given 5 and 60 min following embolization, respectively. Memantine administered 180 min following embolization also increased the P(50) value to 2.69 +/- 2.21 mg, but the response was variable. These results suggest that uncompetitive NMDA antagonists, more specifically open channel blockers, which may be alternatives to high affinity NMDA antagonists, may have substantial therapeutic benefit for the treatment of AIS and memantine or new dual activity analogs of memantine should be further pursued as a useful therapy to treat the behavioral deficits associated with multiple-infarct ischemia.

A 24-week, double-blind, placebo-controlled study of three dosages of Cerebrolysin in patients with mild to moderate Alzheimer's disease

Cerebrolysin (Cere) is a compound with neurotrophic activity shown to be effective in Alzheimer's disease in earlier trials. The efficacy and safety of three dosages of Cere were investigated in this randomized, double-blind, placebo-controlled, study. Two hundred and seventy-nine patients were enrolled (69 Cere 10 ml; 70 Cere 30 ml; 71 Cere 60 ml and 69 placebo). Patients received iv infusions of 10, 30, 60 ml Cere or placebo 5 days/week for the first 4 weeks and thereafter, two iv infusions per week for 8 weeks. Effects on cognition and clinical global impressions were evaluated 4, 12 and 24 weeks after the beginning of the infusions using the CIBIC+ and the modified Alzheimer's Disease Assessment Scale (ADAS)-cog. At week 24, significant improvement of cognitive performance on the ADAS-cog (P=0.038) and global function (CIBIC+; P>0.001) was observed for the 10 ml dose. The 30 and 60 ml doses showed significant improvement of the global outcome but failed to show significant improvement of cognition. The results are consistent with a reversed U-shaped dose-response relationship for Cere. The percentage of patients reporting adverse events was similar across all study groups. Cere treatment was well tolerated and led to significant, dose-dependent improvement of cognition and global clinical impression.

Alzheimer's disease drugs promote neurogenesis

Alzheimer's disease (AD) is associated with increased production of new neurons (neurogenesis), which may be directed at brain repair. However, the effect of drugs used to treat AD on neurogenesis is unknown. We administered tacrine, galantamine or memantine to mouse cerebral cortical cultures in vitro, and to mice in vivo, and measured neurogenesis by labeling newborn cells with bromodeoxyuridine (BrdU) and confirming their neuronal lineage by cell-type-specific protein expression. All three drugs increased BrdU incorporation into cortical cultures in vitro by up to 40%, and increased BrdU labeling of cells in neuroproliferative regions of the adult mouse brain in vivo by 26-45%. BrdU labeling was associated with neuronal markers, such as Hu and betaIII tubulin. Thus, drugs used to treat AD increase cerebral neurogenesis both in vitro and in vivo, which may contribute to their therapeutic effects.

Pharmacological treatment of Alzheimer's Disease

BACKGROUND AND AIMS

The treatment of Alzheimer's disease (AD) is a challenge for physician, families, and patients. An individualized, multimodal treatment plan addressing the treatment of cognitive, behavioural and functional decline is essential. Aim of the paper is to describe the principal components of the treatment plan of AD patients.

METHODS

A review of the recent literature was performed.

RESULTS

Acetylcholinesterase inhibitors (AChEIs) play an important role in the improvement of cognitive decline in mild to moderate AD, even if the improvement is not permanent. Data obtained from the CRONOS project (involving about 500 Alzheimer Evaluation Units) replicate in the real world those obtained in controlled trials, confirming that AD patients may benefit from AChEI treatment. Treatment of behavioral and psychological symptoms of dementia (BPSD) requires education of caregivers, non pharmacological interventions, identification and treatment of medical illnesses or environmental precipitating conditions, specific pharmacological treatment. Traditional neuroleptics are widely used for BPSD treatment, but limited data support their use, and side-effects are frequent and severe. Atypical antipsychotics are effective in treating BPSD, and safer than traditional neuroleptics. However, the increased risk of cerebrovascular accident in patients taking risperidone or olanzapine limited currently their use in demented subjects. The use of antidepressant drugs, as well as behavioral approach, may improve depressive symptoms frequently accompanying AD.

CONCLUSIONS

Although at present there is no cure for AD, several drug treatments and care strategies may improve or stabilize cognitive and behavioral symptoms, and improve the quality of life of patients and families.

Donepezil in patients with severe Alzheimer's disease: double-blind, parallel-group, placebo-controlled study

BACKGROUND

The cholinesterase inhibitor donepezil is used to treat mild-to-moderate Alzheimer's disease. Its efficacy in severe dementia has not been assessed and is controversial. Our aim was to ascertain the effectiveness of donepezil in patients with severe Alzheimer's disease, by focusing primarily on cognition and activities of daily living.

METHODS

We did a 6-month, double-blind, parallel-group, placebo-controlled study in 248 patients with severe Alzheimer's disease (mini mental state examination score 1-10) who were living in assisted care nursing homes ran by trained staff in Sweden. We assigned patients oral donepezil (5 mg per day for 30 days then up to 10 mg per day thereafter, n=128) or matched placebo (n=120). Our primary endpoints were change from baseline to month 6 in the severe impairment battery (SIB) and modified Alzheimer's Disease Cooperative Study activities of daily living inventory for severe Alzheimer's disease (ADCS-ADL-severe). We analysed outcomes for patients with data at baseline and at one or more other timepoints (modified intent-to-treat population) with last observation carried forward used to replace missing data.

FINDINGS

95 patients assigned donepezil and 99 patients assigned placebo completed the study. Patients treated with donepezil improved more in SIB scores and declined less in ADCS-ADL-severe scores at 6 months after initiation of treatment compared with baseline than did controls (least squares [LS] mean difference, 5.7, 95% CI 1.5-9.8; p=0.008, and 1.7, 0.2-3.2; p=0.03, respectively). The incidence of adverse events was comparable between groups (donepezil 82% [n=105] vs placebo 76% [n=91]), with most being transient and mild or moderate in severity. More patients discontinued treatment because of adverse events in the donepezil group (n=20) than in the placebo group (n=8).

INTERPRETATION

Donepezil improves cognition and preserves function in individuals with severe Alzheimer's disease who live in nursing homes.

Prediction of psychosis onset in Alzheimer disease: The role of cognitive impairment, depressive symptoms, and further evidence for psychosis subtypes

BACKGROUND

Psychotic symptoms in Alzheimer disease (AD+P) identify a heritable phenotype associated with more rapid cognitive decline. The authors have proposed that AD+P is itself a composite of a misidentification and a paranoid subtype with increased cognitive impairment restricted to the misidentification type. Most prior studies of the clinical correlates of AD+P have been limited, however, by the inclusion of prevalent cases.

METHODS

Subjects with possible or probable AD or mild cognitive impairment (MCI) without psychosis at study entry were assessed at the time of initial presentation and then annually. Psychotic symptoms were assessed using the CERAD Behavioral Rating Scale. Survival analyses used Cox proportional hazard models with time-dependent covariates to examine the predictors of psychosis onset.

RESULTS

A total of 288 subjects completed at least one follow-up examination. Mean duration of follow-up was 22.1 months. The incidence of psychosis was 0.19 per person-year. Cognitive impairment was associated with onset of psychosis, largely as a result of its association with onset of the misidentification, but not the paranoid, subtype. Including psychotropic medication use in the model revealed an association of antidepressant use with the onset of psychosis. This latter association appeared to arise from an underlying association between depression and the risk of psychosis onset rather than from antidepressant treatment.

CONCLUSION

These findings are consistent with the hypothesis that the misidentification and the paranoid subtypes each define a more biologically homogeneous group than AD+P as a whole. Further exploration of the relationship between depressive symptoms and psychosis in patients with AD is warranted.

Paradigm shift in neuroprotection by NMDA receptor blockade: memantine and beyond

Neuroprotective drugs tested in clinical trials, particularly those that block N-methyl-D-aspartate-sensitive glutamate receptors (NMDARs), have failed miserably in large part because of intolerable side effects. However, one such drug, memantine, was recently approved by the European Union and the US FDA for the treatment of dementia following our group's discovery of its clinically tolerated mechanism of action. Here, we review the molecular basis for memantine efficacy in neurological diseases that are mediated, at least in part, by overactivation of NMDARs, producing excessive Ca(2+) influx through the receptor's associated ion channel and consequent free-radical formation.

Neuroprotection and neurodegenerative diseases: from biology to clinical practice

Neurodegenerative diseases and, in particular, Alzheimer disease, are characterized by progressive neuronal loss correlated in time with the symptoms of the disease considered. Whereas the symptoms of those incapacitating diseases are beginning to be managed with a relative efficacy, the ultimate objective of therapy nonetheless remains preventing cell (neuronal and/or astrocytic) death in a neurocytoprotective approach. In biologic terms, in the light of progress at basic research level, three strategies may be envisaged: (1) antagonizing the cytotoxic causal events (excess intracellular calcium, accumulation of abnormal proteins, excitotoxic effects of amino acids, oxidative stress, processes related to inflammation, etc.); (2) stimulating the endogenous protective processes (anti-free radical or DNA repair systems, production of neurotrophic factors, potential cytoprotective action of steroids, etc.); (3) promoting damaged structure repair strategies (grafts) or deep brain or cortical neurostimulation with a view to triggering (beyond the symptomatic actions) potential 'protective' cell mechanisms. The clinical transition of the various strategies whose efficacy is being tested in animal and/or cell models, experimental analogs of the diseases, and thus the objective demonstration in humans of pharmacological and/or surgical neurocytoprotection, is currently the subject of considerable methodological debate (What are the right psychometric assessment criteria? What are the most pertinent laboratory or neuroradiological markers, etc.?). A number of clinical trials have been completed or are ongoing with drugs that are reputed to be neuroprotective. Thus, elements of the response are beginning to be generated with a view to determining whether it will soon be possible to effectively slow or even stop the neurodegenerative process whose etiology, in most cases, remains obscure.

Treatments for behavioural disorders in neurodegenerative diseases: drug development strategies

Neuropsychiatric symptoms and behavioural alterations are common in neurodegenerative diseases, and effective treatment of these changes represents an important unmet public health need. Imaging, neuropathological, neurotransmitter and molecular genetic studies increasingly identify specific mechanisms that mediate behavioural changes in neurodegenerative disorders and provide a platform for seeking effective therapeutic interventions. Measuring behavioural outcomes in clinical trials of antidementia agents represents an important means of evaluating treatment effectiveness, and clinical trial methodologies and behavioural instrumentation are evolving to facilitate drug development in this important therapeutic target area.

Beta-amyloid-stimulated microglia induce neuron death via synergistic stimulation of tumor necrosis factor alpha and NMDA receptors

Although abundant reactive microglia are found associated with beta-amyloid (Abeta) plaques in Alzheimer's disease (AD) brains, their contribution to cell loss remains speculative. A variety of studies have documented the ability of Abeta fibrils to directly stimulate microglia in vitro to assume a neurotoxic phenotype characterized by secretion of a plethora of proinflammatory molecules. Collectively, these data suggest that activated microglia play a direct role in contributing to neuron death in AD rather than simply a role in clearance after plaque deposition. Although it is clear the Abeta-stimulated microglia acutely secrete toxic oxidizing species, the identity of longer-lived neurotoxic agents remains less defined. We used Abeta-stimulated conditioned media from primary mouse microglia to identify more stable neurotoxic secretions. The NMDA receptor antagonists memantine and 2-amino-5-phosphopetanoic acid as well as soluble tumor necrosis factor alpha (TNFalpha) receptor protect neurons from microglial-conditioned media-dependent death, implicating the excitatory neurotransmitter glutamate and the proinflammatory cytokine TNFalpha as effectors of microglial-stimulated death. Neuron death occurs in an oxidative damage-dependent manner, requiring activity of inducible nitric oxide synthase. Toxicity results from coincident stimulation of the TNFalpha and NMDA receptors, because stimulations of either alone are insufficient to initiate cell death. These findings suggest the hypothesis that AD brains provide the appropriate microglial-mediated inflammatory environment for TNFalpha and glutamate to synergistically stimulate toxic activation of their respective signaling pathways in neurons as a contributing mechanism of cell death.

Alzheimer's Disease: Issues and Challenges in Primary Care

The challenge in primary care practice is identifying persons with symptoms of Alzheimer's Disease (AD) who often have limited capacity to recognize their own symptoms and attribute cognitive decline to chronic illness or aging. Brief office visit communications without an informant,such as a spouse or adult child rarely uncover mild stage AD. Clinicians in primary care fail to screen older adults for AD on a routine basis be-cause of insufficient time, inadequate reimbursement for services, and uncertainty about the value of an early diagnosis. Although current pharmacologic and behavioral interventions and patient education do not prevent eventual disease progression, they arguably lead to improvements in understanding, self-efficacy, and quality of life for the patient and family.

Current Status and Future Promise of Pharmacotherapeutic Strategies for Alzheimer’s Disease

BACKGROUND AND OBJECTIVE

The pharmacotherapy of Alzheimer's disease (AD) is evolving rapidly. Unless new discoveries continue to emerge to facilitate prevention and effective treatment of the disease, the anticipated burden of this disease on caregivers and society at large will overwhelm resources. The objective of this paper is to review the state of development of approaches likely to yield effective interventional measures with regard to AD in the future.

DESIGN

A comprehensive systematic search of MEDLINE using focused search criteria, a search of reference lists from these studies and reviews, a review of the Cochrane Database of Systematic Reviews, and a hand search of relevant journals was conducted. Selection of articles was based on the clinical focus. Additional inclusion criteria preferentially selected key articles that contained higher-level evidence in accordance with explicit, validated criteria.

RESULTS

Pharmaceutical interventions are being developed and tested that confer neuroprotective benefits by targeting causative mechanisms.

CONCLUSION

The paradigm that AD is pharmacologically unresponsive is shifting. Our understanding of the molecular mechanisms of neurodegeneration will soon allow us to more specifically target and interrupt the processes that contribute to this dementia.

Investigation of the pharmacokinetic and pharmacodynamic interactions between memantine and glyburide/metformin in healthy young subjects: a single-center, multiple-dose, open-label study

BACKGROUND

The high prevalence rates of both Alzheimer's disease (AD) and type 2 diabetes mellitus in the elderly population suggest that concomitant pharmacotherapy is likely. Given the renal tubular transport and extensive urinary excretion of memantine and metformin, it was of interest to assess the pharmacokinetic and pharmacodynamic interaction with glyburide/metformin.

OBJECTIVE

The primary goal of this study was to determine whether an in vivo pharmacokinetic or pharmacodynamic interaction exists between memantine (an uncompetitive, moderate-affinity, N-methyl-D-aspartate receptor antagonist with fast blocking/unblocking kinetics that is available in the United States for moderate to severe AD) and glyburide/metformin (a combination pharmacotherapy formulation approved for glycemic control in patients with type 2 diabetes mellitus).

METHODS

In this single-center, multiple-dose, open-label study, healthy adult subjects received a single oral dose of memantine hydrochloride (20 mg) on day 1. After a 14-day washout period, subjects were orally administered 1.25-mg glyburide/250-mg metformin BID with food for 6 days. On day 21, subjects were coadministered memantine (20 mg) and glyburide/metformin with food. Assessments included determination of pharmacokinetic parameters for memantine and the antidiabetic agents when administered alone and in combination, pharmacodynamic measurements of blood glucose levels, and analyses of tolerability.

RESULTS

The study population consisted of 24 subjects (13 women, 11 men; 79.2% white) with a mean (SD) age of 26.1 (5.6) years and a mean (SD) weight of 69.5 (11.3) kg. Twenty-one subjects completed the study: 2 discontinued due to adverse events judged unrelated to study medication, and 1 withdrew consent. No significant pharmacokinetic or pharmacodynamic interactions were observed between memantine and glyburide/metformin. Adverse events included dizziness (41.7% of patients) with memantine administration and gastrointestinal effects (nausea, 9.1 %; vomiting, 9.1%; abdominal cramps, 13.6%) with glyburide/metformin administration.

CONCLUSIONS

No pharmacokinetic interactions between memantine and glyburide/metformin were detected in this study of healthy young volunteers. Memantine had no effect on the pharmacodynamic activities of glyburide and metformin, and the drug combination was well tolerated in this population.

Current Pharmacotherapy for Alzheimer's Disease

Alzheimer's disease (AD) is an age-related neurodegenerative disease that affects approximately 4.5 million people in the United States. The mainstays of current pharmacotherapy for AD are compounds aimed at increasing the levels of acetylcholine in the brain, thereby facilitating cholinergic neurotransmission through inhibition of the cholinesterases. These drugs, known as acetylcholinesterase inhibitors (AChEIs), were first approved by the U.S. Food and Drug Administration (FDA) in 1995 based on clinical trials showing modest symptomatic benefit on cognitive, behavioral, and global measures. In 2004 the FDA approved memantine, an NMDA antagonist, for treating dementia symptoms in moderate to severe AD cases. In clinical practice, memantine may be co-administered with an AChEI, although neither drug individually or in combination affects the underlying pathophysiology of dementia. Dementia in AD results from progressive synaptic loss and neuronal death. As knowledge of the mechanisms responsible for neurodegeneration in AD increases, it is anticipated that neuroprotective drugs to slow or prevent neuronal dysfunction and death will be developed to complement current symptomatic treatments.

The development of anti-amyloid therapy for Alzheimer's disease : from secretase modulators to polymerisation inhibitors

The leading hypothesis of the pathophysiology of Alzheimer's disease holds that the pivotal event is cleavage of the amyloid precursor protein to release intact the 42-amino-acid amyloid-beta peptide (Abeta); this hypothesis best explains the known genetic causes of Alzheimer's disease. If this theory is correct, optimal strategies for altering the disease process should be directed toward modifying the generation, clearance and/or toxicity of Abeta. Abeta is highly aggregable, spontaneously assuming a beta-sheet conformation and polymerising into oligomers, protofibrils, fibrils and plaques. The relative contribution of the various forms of Abeta to neuronal dysfunction in Alzheimer's disease remains uncertain; however, recent evidence implicates diffusible oligomeric species. This article reviews the range of strategies that have been investigated to target Abeta to slow the progression of Alzheimer's disease, from secretase modulators to anti-polymerisation agents. One amyloid-binding drug, tramiprosate (3-amino-1-propanesulfonic acid; Alzhemed), which is effective in reducing polymerisation in vitro and plaque deposition in animals, has now reached phase III clinical trials. Thus, it is plausible that an effective anti-amyloid strategy will become available for the treatment of Alzheimer's disease within the next few years.

A Systematic Review of the Clinical and Cost-Effectiveness of Memantine in Patients with Moderately Severe to Severe Alzheimer???s Disease

Alzheimer's disease (AD) is the most common form of dementia and is characterised by a worsening of cognition, functional ability, and behaviour and mood. The objective of this study was to review the clinical and cost-effectiveness of memantine for the treatment of patients with moderately severe to severe AD. To achieve this, a systematic search and review of the clinical and cost effectiveness literature for memantine was undertaken. The literature search covered the period from the inception of MEDLINE, Cochrane Library, EMBASE and other electronic databases until July 2004. The search included randomised controlled trials (RCTs) and full economic evaluations that assessed the use of memantine in patients with moderately severe to severe AD. Two published RCTs were included in this review; in one of these trials the participants were already being treated with donepezil. The two RCTs showed benefit for patients receiving memantine compared with placebo on the outcome measures of the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory modified for severe dementia, the Clinician's Interview-Based Impression of Change Plus Caregiver Input, and the Severe Impairment Battery, and that memantine appeared to be slightly more effective in patients already receiving a stable dose of donepezil. Five cost-effectiveness studies were included in the review. Although these studies reported cost reductions and improved outcomes with memantine, the evaluations were based on a number of assumptions. In conclusion, memantine appears to be beneficial when assessed using functional and global measurements. However, the effect of memantine on cognitive scores and behaviour and mood outcomes is less clear. Cost-effectiveness is dependent upon assumptions surrounding clinical effect and context-specific cost data.

Pharmacological management of behavioural and psychological disturbance in dementia

Behavioural and psychological symptoms in patients with dementia are common, distressing and often difficult to manage. This review evaluates a range of drugs commonly used to manage these symptoms including antipsychotics, anticonvulsants, antidementia drugs and antidepressants. The risks and benefits of individual treatments are discussed and the relatively poor evidence base and need for further research is highlighted.

Rivastigmine monotherapy and combination therapy with memantine in patients with moderately severe Alzheimer's disease who failed to benefit from previous cholinesterase inhibitor treatment

We investigated the efficacy and safety of rivastigmine alone and combined with memantine in Alzheimer's disease patients previously failing on donepezil or galantamine. This was a prospective, open-label, multicentre study. After stopping donepezil or galantamine, patients received rivastigmine 3-12 mg/day for 16 weeks. Non-responders to rivastigmine monotherapy at week 16 received memantine 5-20 mg/day plus rivastigmine for 12 weeks. The primary efficacy parameter was response (Mini-Mental State Examination equal or better than at week 16) to dual therapy at week 28. Secondary criteria were changes on cognitive and behavioural scales. Two hundred and two patients were included. Ninety-three (46.3%) patients responded to rivastigmine monotherapy. Of 86 patients receiving additional memantine for another 12 weeks, 67 (77.9%) responded. Combination therapy caused no apparent safety concerns. When patients fail on donepezil or galantamine, switching to rivastigmine may improve cognition and behaviour. Should they continue to deteriorate, the addition of memantine may be beneficial.

Adding memantine to rivastigmine therapy in patients with mild-to-moderate alzheimer's disease: results of a 12-week, open-label pilot study

OBJECTIVE

At present, inhibition of cholines-terase is the treatment of choice for subjects with mild-to-moderate Alzheimer's disease (AD). Memantine, a noncompetitive antagonist at N-methyl-d-aspartate receptors, is currently used to treat subjects with moderate-to-severe AD. The goal of this multicenter, open-label pilot study was to investigate whether combination therapy with memantine added to rivastigmine is safe and beneficial in subjects with mild-to-moderate AD.

METHOD

Patients with a DSM-IV diagnosis of dementia of the Alzheimer's type (N = 95), who were treated with rivastigmine (6-12 mg/day) for a maximum duration of 24 weeks prior to baseline, received memantine (5-20 mg/day) in combination with rivastigmine for 12 weeks. The primary efficacy variable was the change in the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) total score at the end of 12 weeks compared with baseline. The study was conducted between September 15, 2003, and May 27, 2004.

RESULTS

There was a statistically significant difference between baseline and week 12 for the ADAS-cog total score, showing a positive effect of combination therapy. Combination therapy did not evidence any unexpected safety concerns and was well-tolerated by most patients.

CONCLUSION

Memantine in combination with rivastigmine appears to be safe and beneficial in patients with mild-to-moderate AD. Our results need to be confirmed in a large, long-term, randomized, double-blind, placebo-controlled clinical trial.

Recommendations for best practices in the treatment of Alzheimer's disease in managed care

BACKGROUND

Alzheimer's disease and related dementias (ADRDs) are increasingly recognized as important causes of impaired cognition, function, and quality of life, as well as excess medical care utilization and costs in the elderly Medicare managed care population. Evidence-based clinical practice guidelines for ADRDs were published in 2001. More recent studies have resulted in the approval of new agents and demonstrated an expanded role for antidementia therapy in various types of dementia, settings of care, stages of disease, and the use of combination therapy. However, these clinical guidelines have not been updated in the past few years.

OBJECTIVE

The goal of this article was to provide practical recommendations developed by a panel of experts that address issues of early diagnosis, treatment, and care management of ADRDs. The panel also addressed the societal and managed care implications.

METHODS

A panel of leading experts was convened to develop consensus recommendations for the treatment and management of dementia based on currently available evidence and the panel's informed expert opinion. The panel comprised 12 leading experts, including clinical investigators and practitioners in geriatric medicine, neurology, psychiatry, and psychology; managed care medical and pharmacy directors; a health systems medical director; and a health policy expert. In addition, articles were collected based on PubMed searches (2000-2005) that were relevant to the key issues identified. Search terms included Alzheimer's disease, dementia, clinical practice guidelines, clinical trials, screening and assessment, and managed care.

RESULTS

ADRDs represent a significant clinical and economic burden to individuals and society, including Medicare managed care organizations (MCOs). Appropriate utilization of antidementia therapy and care management is vitally important to achieving quality of life and care for dementia patients and their caregivers, and for managing the excess costs of Alzheimer's disease. The recommendations address relevant, practical, and timely concerns that are faced on a daily basis by practitioners and by Medicare MCO medical management programs in the care of dementia patients. These consensus recommendations attempt to describe a reasonable current standard for the provision of quality care for patients with dementia. The panel recommendations support the use of screening for cognitive impairment and the use of antidementia therapy for ADRDs in different stages of disease and types of dementia in all clinical settings. The panel members evaluated the use of the 3 marketed cholinesterase inhibitors-donepezil, galantamine, and rivastigmine-as well as the N-methyl-D-aspartate antagonist memantine. Recommendations for using these medications are made with an appreciation of the difficulties in translating the results from investigational clinical trials into clinical practice.

CONCLUSIONS

The recommendations of the expert panel represent a clear consensus that nihilism in the diagnosis, treatment, and management of ADRDs is unwarranted, impairs quality of care, and is ultimately not costeffective.

Current treatment of mild cognitive impairment and alzheimer’s disease

Current therapy for Alzheimer's disease (AD) consists of two classes of drugs: the cholinesterase inhibitors, of which there are three currently available medications; and the glutamate modulators, of which there is one. There has been no new information regarding efficacy of the cholinesterase inhibitors or memantine in AD over the past year, but a large, randomized trial concerning mild cognitive impairment was reported. Donepezil delayed conversion to dementia for 12 months but not longer in that trial, whereas vitamin E had no impact on outcomes. The results of the first immunization therapy for AD were released in 2005. Adverse events forced the premature discontinuation of the trial, but there were some grounds for optimism about the basic approach. Several new agents targeted directly at amyloid beta peptide production are currently in clinical trials, but no large studies have been reported over the past year.

Efficacy and Safety of Memantine in Moderate-to-Severe Alzheimer Disease: The Evidence to Date

Memantine, a moderate-affinity, uncompetitive N-methyl-D-aspartate receptor antagonist, is currently the only agent approved for moderately severe to severe Alzheimer disease (AD) in Europe and for moderate-to-severe Alzheimer disease in the United States. In clinical trials, memantine has consistently demonstrated a reduced rate of deterioration on global, cognitive, functional, and behavioral measures, across a range of outcome measures compared with usual care. Notably, improvements versus placebo were seen in individual activities of daily living and behavior, particularly agitation. Efficacy was demonstrated in patients with newly diagnosed Alzheimer disease, patients previously or currently receiving acetylcholinesterase inhibitors, and both institutionalized and community-dwelling Alzheimer disease patients. Memantine has a tolerability profile similar to placebo. This review presents the results of key clinical trials, and includes clinically relevant analyses, such as numbers-needed-to-treat and effect sizes. Increased dependency and institutionalization are significant cost drivers in Alzheimer disease. Memantine is able to reduce dependency, caregiver time required, and mean monthly caregiver and societal costs. Recent studies of the relationship between Alzheimer disease progression, caregiver burden, and healthcare costs emphasize the need for treatments such as memantine that can slow the rate of decline in Alzheimer disease.