Donepezil for the symptomatic treatment of patients with mild to moderate Alzheimer's disease: a meta-analysis of individual patient data from randomised controlled trials

Collaborative research between academia and industry using a large clinical trial database: a case study in Alzheimer's disease

Background

Large clinical trials databases, developed over the course of a comprehensive clinical trial programme, represent an invaluable resource for clinical researchers. Data mining projects sponsored by industry that use these databases, however, are often not viewed favourably in the academic medical community because of concerns that commercial, rather than scientific, goals are the primary purpose of such endeavours. Thus, there are few examples of sustained collaboration between leading academic clinical researchers and industry professionals in a large-scale data mining project. We present here a successful example of this type of collaboration in the field of dementia.

Methods

The Donepezil Data Repository comprised 18 randomised, controlled trials conducted between 1991 and 2005. The project team at Pfizer determined that the data mining process should be guided by a diverse group of leading Alzheimer's disease clinical researchers called the "Expert Working Group." After development of a list of potential faculty members, invitations were extended and a group of seven members was assembled. The Working Group met regularly with Eisai/Pfizer clinicians and statisticians to discuss the data, identify issues that were currently of interest in the academic and clinical communities that might lend themselves to investigation using these data, and note gaps in understanding or knowledge of Alzheimer's disease that these data could address. Leadership was provided by the Pfizer Clinical Development team leader; Working Group members rotated responsibility for being lead and co-lead for each investigation and resultant publication.

Results

Six manuscripts, each published in a leading subspecialty journal, resulted from the group's work. Another project resulted in poster presentations at international congresses and two were cancelled due to resource constraints.

Conclusions

The experience represents a particular approach to optimising the value of data mining of large clinical trial databases for the combined purpose of furthering clinical research and improving patient care. Fruitful collaboration between industry and academia was fostered while the donepezil data repository was used to advance clinical and scientific knowledge. The Expert Working Group approach warrants consideration as a blueprint for conducting similar research ventures in the future.

Predicting cognitive decline in Alzheimer's disease: an integrated analysis

BACKGROUND

Numerous patient- and disease-related factors increase the risk of rapid cognitive decline in patients with Alzheimer's disease (AD). The ability of pharmacological treatment to attenuate this risk remains undefined.

METHODS

Pooled data from 14 randomized clinical studies of donepezil in the treatment of AD (N = 3748) were analyzed to identify predictors of fast decline and determine the effect of donepezil on the risk of fast decline.

RESULTS

Young age and more severe baseline cognitive, global, or behavioral status were identified as independent predictors of faster decline in placebo-treated patients. Multivariate models indicated that donepezil treatment was associated with a 39% to 63% reduction in the risk of faster decline.

CONCLUSIONS

These results correspond with previous findings, indicating relationships between age or baseline disease severity and rates of cognitive decline. Furthermore, they suggest that symptomatic therapy for AD could reduce the likelihood of faster decline in treated patients.

Safety and tolerability of donepezil 23 mg in moderate to severe Alzheimer's disease

Background

Donepezil 23 mg/d, recently approved in the United States for treatment of moderate to severe Alzheimer's disease (AD), was developed to address the need for an additional treatment option for patients with advanced AD. This report, based on a pivotal phase 3 study, presents a detailed analysis of the safety and tolerability of increasing donepezil to 23 mg/d compared with continuing 10 mg/d.

Method

Safety analyses comprised examination of the incidence, severity, and timing of treatment-emergent adverse events (AEs) and their relationship to treatment initiation; changes in weight, electrocardiogram, vital signs, and laboratory parameters; and the incidence of premature study discontinuation. The analysis population (n = 1434) included all randomized patients who took at least 1 dose of study drug and had a postbaseline safety assessment. To further examine the effect of transition from a lower to a higher donepezil dose, a pooled analysis of safety data from 2 phase 3 trials of donepezil 5 mg/d and 10 mg/d was also performed.

Results

The safety population comprised 1434 patients: donepezil 23 mg/d (n = 963); donepezil 10 mg/d (n = 471); completion rates were 71.1% and 84.7%, respectively. The most common AEs were nausea, vomiting, and diarrhea (donepezil 23 mg/d: 11.8%, 9.2%, 8.3%; donepezil 10 mg/d: 3.4%, 2.5%, 5.3%, respectively). AEs that contributed most to early discontinuations were vomiting (2.9% of patients in the 23 mg/d group and 0.4% in the 10 mg/d group), nausea (1.9% and 0.4%), diarrhea (1.7% and 0.4%), and dizziness (1.1% and 0.0%). The percentages of patients with AEs in the 23 mg/d group, as well as the timing, type, and severity of these AEs, were similar to those seen in previous donepezil trials with titration from 5 to 10 mg/d. Serious AEs were uncommon (23 mg/d, 8.3%; 10 mg/d, 9.6%).

Discussion

The 23 mg/d dose of donepezil was associated with typical cholinergic AEs, particularly gastrointestinal-related AEs, similar to those observed in studies with a dose increase from 5 to 10 mg/d.

Conclusion

The good safety and predictable tolerability profile for donepezil 23 mg/d supports its favorable risk/benefit ratio in patients with moderate to severe AD.

Trial Registration

NCT00478205

Progressive cholinergic decline in Alzheimer's Disease: consideration for treatment with donepezil 23 mg in patients with moderate to severe symptomatology

Of the estimated 5.3 million people with Alzheimer's disease in the United States, more than half would be classified as having moderate or severe disease. Alzheimer's disease is a progressive disorder with the moderate to severe stages generally characterized by significant cognitive, functional, and behavioral dysfunction. Unsurprisingly, these advanced stages are often the most challenging for both patients and their caregivers/families. Symptomatic treatments for moderate to severe Alzheimer's disease are approved in the United States and include the acetylcholinesterase inhibitor donepezil and the glutamate receptor antagonist memantine. Progressive symptomatic decline is nevertheless inevitable even with the available therapies, and therefore additional treatment options are urgently needed for this segment of the Alzheimer's disease population. An immediate-release formulation of donepezil has been available at an approved dose of 5-10 mg/d for the past decade. Recently, the United States Food and Drug Administration approved a higher-dose (23 mg/d) donepezil formulation, which provides more gradual systemic absorption, a longer time to maximum concentration (8 hours) versus the immediate-release formulation (3 hours), and higher daily concentrations. Herein, we review (1) the scientific data on the importance of cholinergic deficits in Alzheimer's disease treatment strategies, (2) the rationale for the use of higher-dose acetylcholinesterase inhibitors in patients with advanced disease, and (3) recent clinical evidence supporting the use of higher-dose donepezil in patients with moderate to severe Alzheimer's disease.

Effectiveness and tolerability of high-dose (23 mg/d) versus standard-dose (10 mg/d) donepezil in moderate to severe Alzheimer's disease: A 24-week, randomized, double-blind study

BACKGROUND

Currently approved Alzheimer's disease (AD) treatments have been reported to provide symptomatic benefit, without proven impact on clinical progression. We hypothesized that the loss of initial therapeutic benefit over time may be mitigated by higher doses of a cholinesterase inhibitor.

OBJECTIVE

The aim of this study was to determine the effectiveness and tolerability of increasing donepezil from 10 to 23 mg/d in patients with moderate to severe AD.

METHODS

This randomized, double-blind study was conducted at 219 sites in Asia, Europe, Australia, North America, South Africa, and South America from June 6, 2007, to March 27, 2009. Patients aged 45 to 90 years with probable AD, Mini-Mental State Examination score 0 to 20 (moderate to severe impairment), and who were receiving donepezil 10 mg once daily for > or =12 weeks before the start of the study were eligible. Patients (n = 1467) were randomly assigned to receive high-dose donepezil (23 mg once daily) or standard-dose donepezil (10 mg once daily) for 24 weeks. Coprimary effectiveness measures were changes in cognition and global functioning, as assessed using least squares mean changes from baseline (LSM [SE] A) scores (last observation carried forward) on the Severe Impairment Battery (SIB; cognition) and the Clinician's Interview-Based Impression of Change Plus Caregiver Input scale (CIBIC+; global function rating) overall change score (mean [SD]) at week 24. Treatment-emergent adverse events (TEAEs) were assessed using spontaneous patient/caregiver reporting and open-ended questioning; clinical laboratory testing (hematology, biochemistry, and urinalysis panels analyzed by a central laboratory); 12-lead ECG; and physical and neurologic examinations, including vital sign measurements.

RESULTS

The effectiveness analyses included 1371 patients (mean age, 73.8 years; 62.8% female; 73.5% white; weight range, 34.0-138.7 kg). A total of 296 of 981 patients (30.2%) withdrew from the donepezil 23-mg/d group; 87 of 486 patients (17.9%) withdrew from the donepezil 10-mg/d group. At study end (week 24), the LSM (SE) Delta in SIB score was significantly greater with donepezil 23 mg/d than with donepezil 10 mg/d (+2.6 [0.58] vs +0.4 [0.66], respectively; difference, 2.2; P < 0.001). The between-treatment difference in CIBIC+ score was nonsignificant (4.23 [1.07] vs 4.29 [1.07]). In post hoc analysis, LSM Delta in SIB score and CIBIC+ treatment effect at end point were greater with donepezil 23 mg/d than 10 mg/d in patients with more advanced AD compared with less impaired patients (SIB, +1.6 [0.78] vs -1.5 [0.88], respectively [P < 0.001]; CIBIC+, 4.31 [1.09] vs 4.42 [1.10] [P = 0.028]). TEAEs were reported in 710 of 963 patients (73.7%) who received donepezil 23 mg/d and in 300 of 471 patients (63.7%) who received donepezil 10 mg/d. With donepezil 23 mg/d, mild, moderate, and severe TEAEs were reported in 297 (30.8%), 332 (34.5%), and 81 (8.4%) patients, respectively; with donepezil 10 mg/d, these proportions were 147 (31.2%), 119 (25.3%), and 34 (7.2%). The 3 most common severe AEs reported with the 23-mg/d dose were nausea (9 patients [0.9%] vs 1 [0.2%] with the 10-mg/d dose), dizziness (7 [0.7%] vs 1 [0.2%]), and vomiting (6 [0.6%] vs 0). The most commonly reported TEAEs considered probably related to treatment with the 23-mg/d dose were nausea (59 patients [6.1%] vs 9 [1.9%] with the 10-mg/d dose), vomiting (48 [5.0%] vs 4 [0.8%]), and diarrhea (31 [3.2%] vs 7 [1.5%]).Thirteen deaths were reported during the study or within 30 days of study discontinuation (23 mg/d, 8 patients [0.8%]; 10 mg/d, 5 patients [1.1%]); all were considered unrelated to the study medication.

CONCLUSIONS

In this study in patients with moderate to severe AD, donepezil 23 mg/d was associated with greater benefits in cognition compared with donepezil 10 mg/d. The between-treatment difference in global functioning was not significant in the overall population. Patients with more advanced AD appeared to benefit from donepezil 23 mg/d on the assessment of global functioning, but this observation requires additional studies for confirmation. ClinicalTrials.gov identifier: NCT00478205.

Donepezil: A Review of Pharmacological Characteristics and Role in the Management of Alzheimer Disease

Donepezil is a potent, selective, noncompetitive, and rapidly reversible inhibitor of acetylcholinesterase (AChEI) licensed for the treatment of Alzheimer disease (AD); and is the first and only AChEI licensed for the treatment of severe AD. Its efficacy as monotherapy, or in combination with the NMDA-agonist, memantine, has been documented in several randomised double-blind, placebo-controlled, short-term clinical trials, as well as long-term extension trials and observational studies. Donepezil is a well tolerated drug that is generally safe as demonstrated even in patients with multiple co-morbidities receiving polypharmacy. It has been shown that donepezil improves cognition and global function in patients with mild-to-moderate AD; and long-term efficacy is maintained for up to 50 weeks. There is a dose-response relationship, with higher doses more likely to produce symptomatic benefit. Furthermore, donepezil-treated patients may improve cognitively and show global clinical improvement in all disease stages, including severe AD. Less consistent results in all disease stages were obtained on measures of function and behavior, and observations of mood. No effect on transition to AD has been found in long-term, randomized clinical trials in mild cognitive impairment (MCI). Cost-effectiveness of the treatment has been questioned by one long-term open-label societal study of 2-years duration. This study reported modest improvement of cognition but no statistically significant benefits during donepezil treatment as compared to placebo, in terms of rates of institutionalization and progression toward greater disability. However, there is a need for further research on clinically meaningful outcomes and treatment benefits favored by patients and caregivers, which are traditionally not defined as outcomes in clinical trials. Likewise, we need to know how to select responders, what is an optimal AChE inhibition particularly during the long-term treatment, in which patients the dosage should be increased for a sustained benefit, what is the optimal duration of treatment and when is meaningful to stop the treatment. After almost two decades of donepezil use in everyday clinical practice these issues are still unresolved.

Efficacy and safety of donepezil in patients with Alzheimer's disease in assisted living facilities

The aim of this 12-week, open-label study was to determine the safety and efficacy of donepezil in participants with Alzheimer's disease (AD) residing in assisted living facilities (ALFs). Participants received 5 mg donepezil daily for 6 weeks followed by 10 mg daily for 6 weeks. Primary and secondary outcomes were change from baseline in Mini-Mental State Examination (MMSE) and Neuropsychiatric Inventory 8 (NPI-8) scores, respectively. Safety was assessed by adverse events (AEs) and laboratory tests. Of the 97 participants, 76 completed the study. Mean MMSE score (18.7 at baseline) improved 1.8 points (P < .0001) at study end. Total NPI-8 score improved 1.8 points (P = .043). The most frequent AEs were nausea and diarrhea. Donepezil improved cognition and behavior and was safe and well tolerated. The results suggest a need for proactive screening and diagnosis of AD and support the value of treatment and use of donepezil in participants residing in ALFs.

Rates of cognitive change in Alzheimer disease: observations across a decade of placebo-controlled clinical trials with donepezil

Treatment success in Alzheimer disease (AD) trials is generally based on benefits over placebo-treated controls. Consequently, variation in rates of decline among placebo-treated patients could impact outcomes from AD trials. In the present analyses, individual patient data [baseline Mini-Mental State Examination (MMSE): 10 to 26] were pooled from randomized, placebo-controlled studies of donepezil for AD conducted during the 1990s, and grouped by initiation year-group 1: 1990 to 1994; group 2: 1996 to 1999. Changes in MMSE and Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) were compared between groups 1 and 2 for placebo, and then between donepezil and placebo. Data were available from 3403 patients in 13 trials. Group 2 (post-1995) included patients with lower baseline MMSE scores, older patients, fewer males, more comorbidity, and more concomitant medications. MMSE decline by week 24 was significantly greater among group 1 (pre-1995) placebo patients versus group 2; a similar trend was observed with the ADAS-cog. Nevertheless, donepezil-mediated treatment effects were consistent over the decade of enrollment. These analyses suggest that patients are showing slower rates of cognitive decline in more recent trials compared with older trials, although having more comorbidities. This finding may have important potential implications for future clinical trial design.

Aspects of beta-amyloid as a biomarker for Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disorder that results in progressive cognitive impairment and death. The accumulation of beta-amyloid (Abeta) in specific brain regions is believed by many to represent the earliest event in the pathogenesis of the disease. Here, we review the key aspects of Abeta as a biomarker for Alzheimer's disease, including the pathogenicity of Abeta, the possible biological functions of its precursor protein, the Abeta metabolism and homeostasis, the diagnostic performance of different Abeta assays in different settings and the potential usefulness of Abeta as a surrogate marker for treatment efficacy in clinical trials of novel Abeta-targeting drugs against Alzheimer's disease.

Combination of intensive cognitive rehabilitation and donepezil therapy in Alzheimer's disease (AD)

Acetylcholinesterase inhibitors (AchEIs) are extensively used in Alzheimer's disease (AD) while reality orientation therapy (ROT) is a cognitive rehabilitation indicated for mentally deteriorated patients. We aimed to evaluate the efficacy of the combination of donepezil with an intensive ROT with active participation of the caregiver. Patients with AD (n=100, mean age 78.4±4.3 years) initiated treatment with donepezil, 5mg/day; 62 of them underwent a 3-week, daily ROT and physical reactivation training with the caregiver (Group A); 38 participants received only donepezil therapy (Group B). All subjects were tested for cognitive and functional abilities at baseline, at the end of the training program, and after 2 months of follow-up. There was a significant improvement in mini-mental state examination (MMSE) score (p<0.001) and the AD assessment scale-cognitive (ADAS-Cog) subscale (p<0.001), without changes in impaired activity of daily living (ADL) and instrumental ADL (IADL) after intensive ROT training in Group A. MMSE was maintained after 2 months in-home ROT continuation. There were no significant changes in MMSE in drug-only treated patients (Group B) after 3 weeks, with a non-significant tendency to improvement in ADAS-Cog. Our results suggest benefit of an intensive ROT program in dementia patients receiving donepezil that seems to be maintained as far as ROT is continued by the caregiver.

Donepezil treatment in severe Alzheimer's disease: a pooled analysis of three clinical trials

OBJECTIVE

Individual clinical trials have demonstrated benefits of donepezil in patients with severe Alzheimer's disease (AD). Data were pooled from three randomized, placebo-controlled trials of donepezil for severe AD to further evaluate treatment effects and overall tolerability/safety.

METHODS

Total scores and sub-scores were analyzed for measures of cognition, global function, function, and behavior. Additional analyses were performed to investigate (1) relationships between cognitive, functional, and behavioral changes, and (2) patterns of combined domain response.

RESULTS

Using pooled total scores, significant treatment differences at endpoint in favor of donepezil were observed for cognition, global function (both p < 0.0001), and function (p = 0.03), with an effect size (Cohen's d) of 0.51, 0.26, and 0.17, respectively. There was no significant treatment difference for behavior. However, donepezil-treated patients with stabilized/improved cognition tended to show significant improvements in function and behavior over placebo-treated patients. Patients treated with donepezil were 2-3 times more likely to achieve a combined domain response than placebo-treated patients (p < 0.0001). Adverse events were as expected for cholinergic therapy, and mortality rates were similar between the treatment groups.

CONCLUSIONS

These findings suggest measurable donepezil-mediated symptomatic benefits in cognition, global function, and daily living activities in patients with severe AD. The treatment effects support the importance of cholinesterase inhibition as a clinically relevant therapeutic option across the spectrum of AD.

Smell identification test as a treatment response marker in patients with Alzheimer disease receiving donepezil

BACKGROUND

Olfactory dysfunction, impaired odor identification in particular, is known to occur in Alzheimer disease (AD). The entorhinal cortex and the olfactory bulb, critical areas for olfactory function, are rich in acetylcholine, the neurotransmitter implicated in AD pathology and treatment. In view of the common anatomical substrate, we aimed to determine whether performance on an olfaction test can be used as a clinical marker for monitoring the efficacy of donepezil in elderly people with AD.

METHODS

Twenty-five participants with mild to moderate AD, planned for donepezil treatment, were recruited from mental health services for older adults in this open-labeled study. Assessments before commencing donepezil included Mini-Mental State Examination, Neuropsychiatric Inventory, Bristol Activities of Daily Living, and the University of Pennsylvania Smell Identification Test. After 3 months of treatment, the primary outcome measure, the Clinician Interview Based Impression of Change plus caregiver input (CIBIC-plus), was completed, and the baseline assessments were repeated.

RESULTS

Eighteen patients continued to receive donepezil at follow-up. The CIBIC-plus outcome correlated with changes in University of Pennsylvania Smell Identification Test and Bristol Activities of Daily Living scores from the baseline (r = 0.7, P < 0.01). In addition, it was the change in smell identification function after treatment that best predicted CIBIC-plus outcome (P < 0.05) on ordinal regression analysis.

CONCLUSIONS

Smell identification function could be useful as a clinical measure to assess treatment response with donepezil in AD. This is a nonblind uncontrolled study, and the outcome indicates the need for a controlled study.

Novel regimens and delivery systems in the pharmacological treatment of Alzheimer's disease

The mainstay of current management of patients with Alzheimer's disease involves drugs that provide symptomatic therapy. Research approaches for future therapy of Alzheimer's disease are focusing on disease modifying and/or preventive approaches. Two classes of medications have been approved by the US FDA for the treatment of Alzheimer's disease: the cholinesterase inhibitors (tacrine, donepezil, rivastigmine, galantamine), mostly for mild to moderate Alzheimer's disease, and the noncompetitive NMDA receptor antagonist memantine for the moderate to severe stages of Alzheimer's disease. Management of comorbid medical problems can be more complex in patients with dementia than in those without dementia. Unfortunately, medication adherence in Alzheimer's disease is low and good adherence is essential for attempting to slow disease progression and improve or stabilize quality of life. Simplifying treatment regimens and providing more caregiver- and patient-friendly modes of administration that fit in better with daily routines can ease caregiver stress which, in turn, may have a favourable impact on the patient's condition. To overcome problems of medication adherence in the elderly, simple, user-friendly dosage regimens should be prescribed for all medications; thus the need for novel regimens and delivery systems in the pharmacological treatment of Alzheimer's disease, such as once-daily donepezil, memantine and galantamine, and transdermal rivastigmine.

Variability of AChE, BChE, and ChAT genes in the late-onset form of Alzheimer's disease and relationships with response to treatment with Donepezil and Rivastigmine

Several factors are believed to give rise to the late onset sporadic form of Alzheimer's disease (LOAD). We have studied the variation at the genes of three enzymes of the cholinergic system: acetylcholinesterase, butyrylcholinesterase, and choline acetyltransferase. The single nucleotide polymorphisms (SNPs) examined were: AChE rs2571598, BChE rs1355534, BChE rs1803274, and ChAT rs2177369. The sample for the case-control study was 471 LOAD patients aged 60 years or older, and 254 subjects with no neurodegenerative disorders as the control group. A significant difference in the genotype distribution between patients and controls was observed only for ChAT rs2177369, showing that the G/G genotype was to be considered a risk factor with respect to the G/A + A/A genotypes (odds ratio = 1.56; 95% Confidence Interval = 1.10-2.22; P = 0.01). Though indicating a significant association with AD onset, our results are far from definitive since contrast with the ones reported by other authors in a previous case-control study, and call for further investigations. Among patients, 171 took part in an observational study concerning the possible role of the genetic composition on the efficacy of treatment with Donepezil and Rivastigmine. We related the SNPs of the above cited genes with cognitive status measured by MMSE. Carrying an allele or a genotype of these SNPs does not seem to play a relevant role in the response to treatment with the two cholinesterase inhibitors, though some significant results were found associated with the AChE A/A genotype that had the best response when treated with Rivastigmine.

Clinical effects of high oral dose of donepezil for patients with Alzheimer's disease in Japan

BACKGROUND

Donepezil 10 mg/day gained approval in Japan in August 2007 for the treatment of cognitive dysfunction in advanced Alzheimer's disease.

METHODS

We evaluated the efficacy and adverse effects of donepezil when the dose was increased to 10 mg/day in 61 Japanese patients with Alzheimer's disease. Cognitive function was evaluated using the Revised Hasegawa Dementia Scale and mini-mental state examination at the day before starting, and at 4, 8 and 24 weeks after starting donepezil 10 mg/day. The relationship with apolipoprotein E4 was also investigated.

RESULTS

The Revised Hasegawa Dementia Scale and mini-mental state examination scores were not statistically significantly different at any time after starting donepezil 10 mg/day. It can be anticipated that donepezil 10 mg/day will especially inhibit deterioration of cognitive function in advanced Alzheimer's disease. The incidence of adverse events was 11.5%, lower than the rate of 40% or higher recorded during previous clinical trials.

CONCLUSIONS

The progression of cognitive dysfunction could be inhibited by increasing the dose of donepezil to 10 mg/day. It was suggested that longer-term treatment with 5 mg/day might lead to fewer adverse events when the dose is increased to 10 mg/day.

Multidimensional classification of hippocampal shape features discriminates Alzheimer's disease and mild cognitive impairment from normal aging

We describe a new method to automatically discriminate between patients with Alzheimer's disease (AD) or mild cognitive impairment (MCI) and elderly controls, based on multidimensional classification of hippocampal shape features. This approach uses spherical harmonics (SPHARM) coefficients to model the shape of the hippocampi, which are segmented from magnetic resonance images (MRI) using a fully automatic method that we previously developed. SPHARM coefficients are used as features in a classification procedure based on support vector machines (SVM). The most relevant features for classification are selected using a bagging strategy. We evaluate the accuracy of our method in a group of 23 patients with AD (10 males, 13 females, age+/-standard-deviation (SD)=73+/-6 years, mini-mental score (MMS)=24.4+/-2.8), 23 patients with amnestic MCI (10 males, 13 females, age+/-SD=74+/-8 years, MMS=27.3+/-1.4) and 25 elderly healthy controls (13 males, 12 females, age+/-SD=64+/-8 years), using leave-one-out cross-validation. For AD vs controls, we obtain a correct classification rate of 94%, a sensitivity of 96%, and a specificity of 92%. For MCI vs controls, we obtain a classification rate of 83%, a sensitivity of 83%, and a specificity of 84%. This accuracy is superior to that of hippocampal volumetry and is comparable to recently published SVM-based whole-brain classification methods, which relied on a different strategy. This new method may become a useful tool to assist in the diagnosis of Alzheimer's disease.

The Item-Specific Deficit Approach to evaluating verbal memory dysfunction: rationale, psychometrics, and application

In the current study, we introduce the Item-Specific Deficit Approach (ISDA), a novel method for characterizing memory process deficits in list-learning data. To meet this objective, we applied the ISDA to California Verbal Learning Test (CVLT) data collected from a sample of 132 participants (53 healthy participants and 79 neurologically compromised participants). Overall, the ISDA indices measuring encoding, consolidation, and retrieval deficits demonstrated advantages over some traditional indices and indicated acceptable reliability and validity. Currently, the ISDA is intended for experimental use, although further research may support its utility for characterizing memory impairments in clinical assessments.

Substitute consent for research involving the elderly: a comparison between Quebec and France

The authors first describe the rules enacted in Quebec and France to protect adults with decisional impairment who may be approached by investigators to participate in research protocols. They then present two consecutive postal surveys conducted among Quebec and French researchers in aging and designed to (1) assess their knowledge of the legal provisions implemented to protect decisionally incapable adults, (2) elicit their opinions regarding the person best suited to provide substitute consent for research participation, and (3) document their conduct related to obtaining consent for prospective subjects with impaired decisional capacity. Knowledge of the legislation governing substitute consent was poor, even more so among French than Quebec researchers (p < 0.001). In both samples, the majority of respondents felt that the substitute decision-maker does not have to be legally appointed when the study poses little risk to the participant. Practice data revealed a certain discrepancy between the conduct of researchers in aging and the legal provisions regarding consent for research purposes that prevail in their jurisdictions. These findings underscore the need to better educate clinical investigators about existing measures to protect prospective subjects who lack decisional capacity. They also provide some support for allowing close relatives to consent to research participation on behalf of older adults who are unable to consent by themselves and have not been appointed a legal representative.

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.

Acetylcholine receptors in dementia and mild cognitive impairment

PURPOSE

To clarify whether changes in the cholinergic transmission occur early in the course of Alzheimer's disease (AD), we carried out positron emission tomography (PET) with the radioligand 2-[(18)F]F-A-85380, which is supposed to be specific for alpha4beta2 nicotinic acetylcholine receptors (nAChRs).

METHOD

We included patients with moderate to severe AD and patients with amnestic mild cognitive impairment (MCI), presumed to present preclinical AD.

RESULTS

Both patients with AD and MCI showed significant reductions in alpha4beta2 nAChRs in brain regions typically affected by AD pathology. These findings indicate that a reduction in alpha4beta2 nAChRs occurs during early symptomatic stages of AD. The alpha4beta2 nAChR availability in these regions correlated with the severity of cognitive impairment, indicating a stage sensitivity of the alpha4beta2 nAChR status.

CONCLUSION

Together, our results provide evidence for the potential of 2-[(18)]F-A-85380 nAChR PET in the diagnosis of patients at risk for AD. Because of the extraordinary long acquisition time with 2-[(18)F]F-A-85380, we developed the new alpha4beta2 nAChR-specific radioligands (+)- and (-)-[(18)F]norchloro-fluoro-homoepibatidine (NCFHEB) and evaluated them preclinically. (-)-[(18)F]NCFHEB shows twofold higher brain uptake and significantly shorter acquisition times. Therefore, (-)-[(18)F]NCFHEB should be a suitable radioligand for larger clinical investigations.

Discrimination between Alzheimer disease, mild cognitive impairment, and normal aging by using automated segmentation of the hippocampus

PURPOSE

To prospectively evaluate the accuracy of automated hippocampal volumetry to help distinguish between patients with Alzheimer disease (AD), patients with mild cognitive impairment (MCI), and elderly controls, by using established criteria for patients with AD and MCI as the reference standard.

MATERIALS AND METHODS

The regional ethics committee approved the study and written informed consent was obtained from all participants. The study included 25 patients with AD (11 men, 14 women; mean age +/- standard deviation [SD], 73 years +/- 6; Mini-Mental State Examination (MMSE) score, 24.4 +/- 2.7), 24 patients with amnestic MCI (10 men, 14 women; mean age +/- SD, 74 years +/- 8; MMSE score, 27.2 +/- 1.4) and 25 elderly healthy controls (13 men, 12 women; mean age +/- SD, 64 years +/- 8). For each participant, the hippocampi were automatically segmented on three-dimensional T1-weighted magnetic resonance (MR) images with high spatial resolution. Segmentation was performed by using recently developed software that allows fast segmentation with minimal user input. Group differences in hippocampal volume were assessed by using Student t tests. To obtain robust estimates of P values, the correct classification rate, sensitivity, and specificity, bootstrap methods were used.

RESULTS

Significant hippocampal volume reductions were detected in all groups of patients (-32% in AD patients vs controls, P < .001; -19% in MCI patients vs controls, P < .001; and -15% in AD patients vs MCI patients, P < .01). Individual classification on the basis of hippocampal volume resulted in 84% correct classification (sensitivity, 84%; specificity, 84%) between AD patients and controls and 73% correct classification (sensitivity, 75%; specificity, 70%) between MCI patients and controls.

CONCLUSION

This automated method can serve as an alternative to manual tracing and may thus prove useful in assisting with the diagnosis of AD.

Efficacy and safety of donepezil in patients with schizophrenia or schizoaffective disorder: significant placebo/practice effects in a 12-week, randomized, double-blind, placebo-controlled trial

Altered expression of central muscarinic and nicotinic acetylcholine receptors in hippocampal and cortical regions may contribute to the cognitive impairment exhibited in patients with schizophrenia. Increasing cholinergic activity through the use of a cholinesterase inhibitor (ChEI) therefore represents a possible strategy for cognitive augmentation in schizophrenia. We examined the efficacy and safety of the ChEI donepezil as cotreatment for mild to moderate cognitive impairment in schizophrenia or schizoaffective disorder in a prospective, 12-week, placebo-controlled, double-blind, parallel-group study. In total, 250 patients (18-55 years) with schizophrenia or schizoaffective disorder who were clinically stabilized on risperidone, olanzapine, quetiapine, ziprasidone, or aripiprazole, alone or in combination, were enrolled at 38 outpatient psychiatric clinics in the United States. Patients were randomized to donepezil 5 mg q.d. for 6 weeks then 10 mg q.d. for 6 weeks, or placebo administered as oral tablets. The primary outcome measure was the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) neurocognitive battery composite score. In the intent-to-treat sample (donepezil, n=121; placebo, n=124), both treatments showed improvement in the composite score from baseline to week 12. At week 12, cognitive improvement with donepezil was similar to that with placebo (last-observation-carried-forward effect size, 0.277 vs 0.411; p=0.1182) and statistically significantly inferior for the observed-cases analysis (0.257 vs 0.450; p=0.044). There was statistically significant improvement in the Positive and Negative Syndrome Assessment Scale negative symptoms score for placebo compared with donepezil, while total and positive symptom scores were similar between both treatments. Statistically significant improvements in positive symptoms score and Clinical Global Impression-Improvement for donepezil compared with placebo were noted at Week 6. Treatment-emergent adverse events (AEs) were observed for 54.5% of donepezil- and 61.3% of placebo-treated patients; most AEs were rated as mild to moderate in severity. Donepezil was safe and well-tolerated but was not effective compared with placebo as a cotreatment for the improvement of cognitive impairment in this patient population. A significant and surprisingly large placebo/practice effect was observed among placebo-treated patients, and is a serious consideration in future clinical trial study designs for potential cognitive enhancing compounds in schizophrenia.

Safety and tolerability of donepezil at doses up to 20 mg/day: results from a pilot study in patients with Alzheimer's disease

BACKGROUND

Donepezil is licensed for the treatment of mild-to-moderate Alzheimer's disease (AD) at doses of 5-10 mg/day and has recently been approved in the US for severe AD. Multiple studies have suggested that donepezil 10 mg/day provides additional cognitive and functional benefits over the 5 mg/day dose. Higher doses of donepezil, if safe and well tolerated, might provide further benefits for patients with AD.

OBJECTIVE

To evaluate the safety and tolerability of donepezil at doses of 15 and 20 mg/day.

METHOD

A 24-week, randomized, double-blind, placebo-controlled, pilot study conducted at two investigational sites in the US. Enrolled patients (male and female; aged 50-86 years) had a diagnosis of probable AD at the mild-to-moderate stage (Mini-Mental State Examination [MMSE] score 10-26). All patients had been treated with donepezil 10 mg/day for 12-30 months prior to enrolment. Patients (n = 31) were randomized 1 : 1 to receive either a standard dose of donepezil (donepezil 10 mg/day plus placebo 5 mg/day for weeks 1-12; donepezil 10 mg/day plus placebo 10 mg/day for weeks 13-24) or a higher dose of donepezil (donepezil 15 mg/day for weeks 1-12; donepezil 20 mg/day for weeks 13-24). Primary outcome measures were tolerability (as determined by monitoring of discontinuations, dose modifications and adverse events) and safety (as determined by adverse event monitoring, physical examinations, clinical laboratory tests and ECGs). Psychometric measures (Alzheimer's Disease Assessment Scale-Cognitive Subscale [ADAS-cog], MMSE and Clinician's Interview-Based Impression of Change with caregiver information [CIBIC+]) and pharmacokinetic/pharmacodynamic parameters were secondary outcomes.

RESULTS

No patients withdrew from the study and there were no serious adverse events or deaths. By week 24, 15 of 16 patients in the higher-dose group tolerated the maximum 20 mg/day dose; one patient had a permanent dose reduction to donepezil 15 mg/day. In the standard-dose group, 14 of 15 patients tolerated donepezil 10 mg/day plus placebo 10 mg/day by the end of the study; one patient had a permanent dose reduction to donepezil 10 mg/day plus placebo 5 mg/day. Temporary dose reductions occurred in two patients (one from each group). Adverse events reported were as expected for donepezil and were all mild to moderate in intensity. Adverse events considered to be possibly or probably related to treatment were reported for three patients in the standard-dose group and six patients in the higher-dose group. One patient in the higher-dose group had weight loss reported as possibly or probably treatment related. Mean changes on ECGs were not clinically significant in either group, and the incidence of bradycardia was comparable. No treatment difference on any of the psychometric measures was observed between the groups. Pharmacokinetic analyses showed that an increased donepezil dose was associated with an increase in donepezil plasma concentrations from baseline.

CONCLUSION

In this small pilot study of patients with mild-to-moderate AD already stabilized on donepezil 10 mg/day, doses of 15 and 20 mg/day of donepezil appeared safe and well tolerated. These results justify initiation of larger clinical trials designed to investigate the efficacy and safety of doses of donepezil higher than 10 mg/day in patients with AD.

Randomized controlled trials for schizophrenia: study designs targeted to distinct goals

Randomized controlled trials for antipsychotic drugs have a variety of design features suited to diverse purposes. Efficacy (or explanatory) trials seek to establish if a drug can reduce psychotic symptoms under ideal circumstances. To isolate drug effects, researchers enroll carefully selected patients. Specialized research personnel use rating scales of symptoms that are sensitive to drug effects as the study primary outcomes. Large simple trials (LSTs) are conducted at typical treatment settings with usual clinical personnel and enroll large numbers of participants so small but clinically important differences between treatment options can be detected. LSTs focus narrowly on clearly defined, patient-oriented outcomes. To some extent, practical trials can be conceptualized as hybrids of efficacy and large simple trials. Practical trials provide independent evidence to inform decision makers about the everyday effectiveness of clinically relevant alternative interventions. Practical trial researchers include a heterogeneous population of patients and collect data on a broad range of meaningful health outcomes at many types of practice settings intended to represent usual treatment. The designers of practical trials make trade-offs between internal validity, external validity, the breadth of issues addressed, and the ability to detect small differences. The different objectives of trials should be considered in the interpretation of the complete body of randomized evidence on antipsychotic drugs.

Patient and caregiver outcomes after 6 +/- 1.5-months of rivastigmine therapy for mild-to-moderate Alzheimer's disease: the Belgian FExT study

OBJECTIVE

Despite response variability, cholinesterase inhibitors are recommended in mild to moderate Alzheimer's disease. Dose titration is common; however randomized controlled trials (RCTs) have mainly investigated fixed-dose regimens. We examined practice patterns and outcomes of 6 +/- 1.5-month rivastigmine therapy.

METHODS

Prospective, pharmacoepidemiologic, naturalistic study of 175 evaluable patients with mild to moderate Alzheimer's disease (+ 151 caregivers) from 52 centers in Belgium on 6 +/- 1.5 month (titrated) rivastigmine treatment.

MAIN OUTCOME MEASURES

Measured at baseline (enrollment) and follow-up (6 +/- 1.5 months). For patients: Mini-Mental State Exam (MMSE), Activities of Daily Living (ADL), Neuropsychiatric Inventory (NPI), Global Deterioration Scale (GDS) scores; treatment response (improvement, maintenance, or decline less than normative slope). For caregivers: hours/week spent caring; Zarit Caregiver Burden Scale (ZCBS), 12-item version of General Health Questionnaire (GHQ-12), Instrumental Activities of Daily Living (IADL) scores.

RESULTS

Patients' MMSE and NPI scores (p < 0.001) improved from baseline to follow-up, but not ADL and GDS scores. Treatment response was 89.1% of patients for MMSE (including 60.6% with improvement) and 77.7% for NPI (including 57.1% with improvement). Quadratic curves were fitted for the average daily dose and the MMSE and NPI scores; with a trend towards average daily dose of 6.0 +/- 3.0 mg/day. Caregivers' ZCBS (p = 0.036) and GHQ-12 (p = 0.029) scores improved, but not IADL scores and time spent caring.

CONCLUSIONS

Patients' MMSE and ADL scores confirmed the meta-analyses of rivastigmine efficacy trials, while NPI scores exceeded efficacy results. Proportionately more patients responded to (titrated) treatment than in fixed-dose RCTs. Caregivers reported less burden (similar to meta-analysis) and better general health over the study period. Where efficacy and effectiveness results diverge, the benefit is in 'real-world' effectiveness. Large sample, multi-country replications, less sensitive to censoring secondary to missing data and powered to permit advanced modeling, as well as RCTs with adaptive designs to accommodate titration, are needed. The profile of patients most likely to benefit from treatment or most vulnerable to treatment outcome must be studied, as must the impact of physician- and center-related variables on outcomes.

Efficacy and safety of donepezil over 3 years: an open-label, multicentre study in patients with Alzheimer's disease

OBJECTIVE

This 132-week, open-label extension study assessed the long-term efficacy and safety of donepezil in 579 patients with mild to moderate Alzheimer's disease (AD) who had previously participated in a 24-week double-blind study of 5 or 10 mg/day donepezil vs placebo.

METHOD

Patients enrolled in the present study had a 6-week single-blind placebo washout period followed by treatment with donepezil 5 mg/day for 6 weeks with an optional increase in dosage to 10 mg/day between weeks 6 and 32.

RESULTS

After 6 weeks of open-label treatment with donepezil 5 mg/day, mean Alzheimer's Disease Assessment Scale -- cognitive subscale scores (ADAS-cog) improved by approximately two points, while after 12 weeks of open-label treatment (with a majority of patients receiving 10 mg/day), the mean ADAS-cog score was 1 point better than the score at the end of the placebo washout period. Scores then declined gradually over the remainder of the study. Mean changes in Clinical Dementia Rating-Sum of Boxes scores showed slight improvement over the first 12 weeks of open-label treatment and then slowly declined for the remainder of the study period. Donepezil was well tolerated over the entire 162-week study period. Overall, 85% of patients experienced at least one adverse event (AE). The most common included diarrhoea (12%), nausea (11%), infection (11%) and accidental injury (10%). Some patients discontinued the study due to AEs (15%).

CONCLUSIONS

These results support the conclusion that donepezil is safe and effective for the long-term treatment of patients with mild to moderate AD.

Acetylcholinesterase inhibitors for Alzheimer’s disease

Acetylcholinesterase inhibitor drugs are now a mature treatment approach for Alzheimer’s disease, although they remain controversial. This review addresses the available data on acetylcholinesterase inhibitor treatment in patients with Alzheimer’s disease across multiple outcome types. It addresses rational and evidence-based expectations for treatment in this population.

Global assessment measures for assessing efficacy in dementia drug trials

The use of judgment-based global measures of clinical treatment effects has a long history in the regulatory approval of drugs for the treatment of dementia. This paper reviews current use of these measures, noting several practical difficulties with their implementation. Importantly, global measures have usually yielded general estimates of drug effects similar to psychometric test batteries, even though correlations between global and psychometric measures at the individual patient level is modest. Like psychometric tests, global measures can tell us that some clinically detectable effect is present but often yield only limited evidence about what those effects might be. Steps should be taken to improve the specificity of treatment effect description and to incorporate patient/caregiver preferences in global measures about disease treatment in dementia.

[A contribution to the current discussion on anti-dementia drugs in Germany]

In Germany, the role of acetylcholinesterase inhibitors in the treatment of Alzheimer's disease (AD) has become a topic of recent discussion. The present article addresses issues which, in the opinion of the authors, have not received sufficient attention. These include the distinction between statistical and clinical significance, outcome parameters, the duration of clinical trials, variability in treatment response and the definition of treatment responders. The authors argue that these issues need to be considered in an in-depth evaluation of acetylcholinesterase inhibitors in the treatment of AD.

Relevance of Donepezil in Enhancing Learning and Memory in Special Populations: A Review of the Literature

This review discusses the laboratory and clinical research supporting the rationale for the efficacy of donepezil (Aricept USA) in enhancing cognition in autism, Alzheimer disease, Down syndrome, traumatic brain injury, Attention Deficit Hyperactivity Disorder (ADHD), and schizophrenia. While preliminary animal models have shown effective, human studies exclusive of Alzheimer disease are sparse. Although attention and memory are unlikely a sole operation of the cholinergic system, evidence indicates a promising direction for further examination of this hypothesis in autism. Studies that examine changes in operationally defined behaviors and reliable and valid measure of changes in attention and memory are needed.

100 years and counting: prospects for defeating Alzheimer's disease

This week marks a century since the first description of Alzheimer's disease (AD). Despite approval of several drugs for AD, the disease continues to rob millions of their memories and their lives. Fortunately, many new therapies directly targeting the mechanisms underlying AD are now in the pipeline. Among the investigative AD therapies in clinical trials are several strategies to block pathogenic amyloid-beta peptides and to rescue vulnerable neurons from degeneration. Complementary but less mature strategies aim to prevent the copathogenic effects of apolipoprotein E and the microtubule-associated protein tau. New insights into selective neuronal vulnerability and the link between aging and AD may provide additional entry points for therapeutic interventions. The predicted increase in AD cases over the next few decades makes the development of better treatments a matter of utmost importance and urgency.

Application of Clinical Trial Simulation to Compare Proof-of-Concept Study Designs for Drugs with a Slow Onset of Effect; An Example in Alzheimer's Disease

OBJECTIVE

Clinical trial simulation (CTS) was used to select a robust design to test the hypothesis that a new treatment was effective for Alzheimer's disease (AD). Typically, a parallel group, placebo controlled, 12-week trial in 200-400 AD patients would be used to establish drug effect relative to placebo (i.e., Ho: Drug Effect = 0). We evaluated if a crossover design would allow smaller and shorter duration trials.

MATERIALS AND METHODS

A family of plausible drug and disease models describing the time course of the AD assessment scale (ADAS-Cog) was developed based on Phase I data and literature reports of other treatments for AD. The models included pharmacokinetic, pharmacodynamic, disease progression, and placebo components. Eight alternative trial designs were explored via simulation. One hundred replicates of each combination of drug and disease model and trial design were simulated. A 'positive trial' reflecting drug activity was declared considering both a dose trend test (p < 0.05) and pair-wise comparisons to placebo (p < 0.025).

RESULTS

A 4 x 4 Latin Square design was predicted to have at least 80% power to detect activity across a range of drug and disease models. The trial design was subsequently implemented and the trial was completed. Based on the results of the actual trial, a conclusive decision about further development was taken. The crossover design provided enhanced power over a parallel group design due to the lower residual variability.

CONCLUSION

CTS aided the decision to use a more efficient proof of concept trial design, leading to savings of up to US 4 M dollars in direct costs and a firm decision 8-12 months earlier than a 12-week parallel group trial.

Impact of the CYP2D6 polymorphism on steady-state plasma concentrations and clinical outcome of donepezil in Alzheimer’s disease patients

OBJECTIVE

The aims of this study were to evaluate the impact of the CYP2D6 polymorphism on both the steady-state plasma concentrations (Cp) and the clinical outcome of donepezil, a selective acetylcholinesterase inhibitor used in the treatment of Alzheimer's disease (AD).

METHODS

Forty-two patients of Caucasian ethnicity affected by probable AD were included in the study. All had been receiving therapy with donepezil for at least 3 months: 31 patients with 5 mg/day and 11 patients with 10 mg/day. The CYP2D6 genotype was analysed, and donepezil Cp was measured by using high-performance liquid chromatography.

RESULTS

On the basis of their CYP2D6 genotype, 30 patients could be classified as homozygous extensive metabolizers (EM), 10 as heterozygous EM and 2 as ultrarapid metabolizers (UM). No poor metabolizer was found. The dose and body weight-corrected median donepezil Cp were slightly, though not significantly, lower in homozygous than in heterozygous EM (0.33 vs. 0.41 ng/ml/mg/kg, respectively). The latter group consistently showed a better clinical response to treatment, as measured by change in Mini-Mental State Examination score (median: 1.40 vs. -1.30, respectively). UM patients had lower Cp than EM patients and showed no clinical improvement.

CONCLUSIONS

Our preliminary data suggest that the CYP2D6 polymorphism influences both donepezil metabolism and therapeutic outcome and that a knowledge of a patient's CYP2D6 genotype together with donepezil concentration measurements might be useful in the context of improving the clinical efficacy of donepezil therapy.

Effect of oral donepezil on intraocular pressure in normotensive Alzheimer patients

Donepezil, a selective acetylcholinesterase (AChE) inhibitor, has been shown to reduce intraocular pressure (IOP) in ocular normotensive rabbit eyes. The aim of this investigation was to evaluate the effect of oral donepezil on IOP and pupil diameter after mid-term oral treatment in normotensive persons. Thirty-two newly diagnosed Alzheimer patients with normal IOP and no further antiglaucomatous treatment were included in the study. IOP and pupil diameter were evaluated before and 4 weeks after daily intake of 5 mg donepezil. IOP and pupil diameter were significantly lower/smaller after 4 weeks of treatment. The mean IOP of all 63 eyes was 14.1 mmHg before and 12.8 mmHg after treatment (8.8% reduction). Mean pupil diameter constricted from 3.9 to 3.6 mm (-7.4%). These findings show that donepezil, and, possibly, other selective AChE inhibitors, can potentially be used to treat glaucoma. They are also known to have neuroprotective effects in Alzheimer's, and, therefore, might have an additional therapeutic benefit.

Clinical trials in mild cognitive impairment: lessons for the future

Mild cognitive impairment (MCI) is an operational definition for a cognitive decline in individuals with a greater risk of developing dementia. The amnestic subtype of MCI is of particular interest because these individuals most likely progress to Alzheimer's disease (AD). Currently hypothesised therapeutic approaches in MCI are mainly based on AD treatment strategies. Long term secondary prevention randomised clinical trials have been completed in amnestic MCI populations, encompassing agents with various mechanisms of action: acetylcholinesterase inhibitors (donepezil, rivastigmine, galantamine), antioxidants (vitamin E), anti-inflammatories (rofecoxib), and nootropics (piracetam). The design of clinical trials in MCI is influenced by study objectives and definition of primary end points: time to clinical diagnosis of dementia, and AD in particular, or symptom progression. As none of the drugs previously shown to have clinical efficacy in AD trials or benefit in everyday practice have met the primary objectives of the respective trials, design of future clinical trials in MCI should be further developed particularly as regards the selection of more homogeneous samples at entry, optimal treatment duration, and multidimensional and reliable outcomes.

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.

Donepezil in the treatment of ADHD-like symptoms in youths with pervasive developmental disorder: a case series

BACKGROUND

Recent studies reported ADHD-like symptoms and cognitive deficits in pervasive developmental disorder (PDD). Because work in dementia documents improvement in executive function deficits with the acetylcholinesterase inhibitor donepezil, the authors reason that similar benefits could be obtained in PDD.

METHOD

The authors describe eight cases of PDD youth ages 10 to 17 treated with donepezil targeting ADHD-like symptoms associated with PDD.

RESULTS

Most participants improve ADHD-like symptomatology. In addition, improvement in communication and socialization is noted.

CONCLUSION

Donepezil may have a role in treating ADHD-like symptoms in children with PDD.

Clinical aspects of inflammation in Alzheimer's disease

In Alzheimer's disease (AD) there is increasing evidence that neurotoxicity is mediated by CNS inflammatory processes. These processes involve activation of microglia by amyloid-beta leading to release of pro-inflammatory cytokines including IL-1beta, IL-6, and TNF-alpha among others. Neurotoxic processes mediated by these cytokines may include direct neuronal death by enhancement of apoptosis, decreased synaptic function as evidence by inhibition of long-term potentiation, and inhibition of hippocampal neurogenesis. Central nervous system (CNS) inflammation may predate the development of senile plaques and neurofibrillary tangles in AD and may prove to be a more sensitive marker of prodromal AD. New developments in measuring CNS inflammation include measuring cytokine release by peripheral blood mononuclear cells and the development of PET markers of microglial activation. There is epidemiological evidence that circulating serum IL-6 is associated with poorer cognition. While epidemiological studies suggest a protective effect of NSAIDs against development of AD, controlled trials of NSAIDs to date have not shown any protective effect of drug. New anti-inflammatory agents for treating or preventing AD may include novel NSAIDs and opioid antagonists. These developments provide an alternative or potential adjunct to anti-amyloid therapies for AD.

Alzheimer's disease: the benefits of early treatment

The purpose of this review was to summarize research on the clinical benefits of early treatment for Alzheimer's disease via a focused discussion of data on donepezil. Well-controlled clinical trials demonstrate that donepezil is effective in stabilizing or slowing progressive decline in cognition, function, and behavior. Several studies reveal statistically significant and clinically meaningful advantages to initiating treatment early in the course of the disease. Benefits of donepezil treatment include behavioral stabilization and preserved independence, in addition to slowed cognitive decline. Epidemiologic studies and evidence from histopathology underlie a rationale for treating patients who are cognitively impaired but do not have dementia. Clinical trials in such patients indicate that treating patients with mild cognitive impairment (MCI) may delay the onset of Alzheimer's dementia. Substantial evidence favors initiating treatment early in the course of dementia and reinforces the necessity to assess behavior and activities of daily living to accurately evaluate treatment response. Results of early studies of donepezil in MCI are promising and suggest directions for further research.

Cholinesterase inhibitors for patients with Alzheimer's disease: systematic review of randomised clinical trials

OBJECTIVES

Pharmacological treatment of Alzheimer's disease focuses on correcting the cholinergic deficiency in the central nervous system with cholinesterase inhibitors. Three cholinesterase inhibitors are currently recommended: donepezil, rivastigmine, and galantamine. This review assessed the scientific evidence for the recommendation of these agents.

DATA SOURCES

The terms "donepezil", "rivastigmine", and "galantamine", limited by "randomized-controlled-trials" were searched in Medline (1989-November 2004), Embase (1989-November 2004), and the Cochrane Database of Systematic Reviews without restriction for language.

STUDY SELECTION

All published, double blind, randomised controlled trials examining efficacy on the basis of clinical outcomes, in which treatment with donepezil, rivastigmine, or galantamine was compared with placebo in patients with Alzheimer's disease, were included. Each study was assessed independently, following a predefined checklist of criteria of methodological quality.

RESULTS

22 trials met the inclusion criteria. Follow-up ranged from six weeks to three years. 12 of 14 studies measuring the cognitive outcome by means of the 70 point Alzheimer's disease assessment scale--cognitive subscale showed differences ranging from 1.5 points to 3.9 points in favour of the respective cholinesterase inhibitors. Benefits were also reported from all 12 trials that used the clinician's interview based impression of change scale with input from caregivers. Methodological assessment of all studies found considerable flaws--for example, multiple testing without correction for multiplicity or exclusion of patients after randomisation.

CONCLUSION

Because of flawed methods and small clinical benefits, the scientific basis for recommendations of cholinesterase inhibitors for the treatment of Alzheimer's disease is questionable.

Efficacy and safety of donepezil in patients with more severe Alzheimer's disease: a subgroup analysis from a randomized, placebo-controlled trial

BACKGROUND

There have been very limited investigations of cholinesterase inhibitor therapy in more advanced stages of Alzheimer's disease (AD). The efficacy and safety of donepezil were evaluated in post hoc analyses of a subgroup of patients with more severe AD (standardized Mini-Mental State Examination [sMMSE] score 5-12) within a randomized, placebo-controlled trial in moderate to severe AD (MSAD study). Additional analyses examined whether donepezil's treatment effects were consistent across the full range of baseline AD severity studied (sMMSE score 5-17).

METHODS

Patients with moderate to severe AD (n = 290) who were living in the community or in assisted living facilities received donepezil or placebo for 24 weeks; n = 145 in the more severe AD subgroup. The primary outcome measure was the Clinician's Interview-Based Impression of Change (CIBIC-plus) with secondary outcomes including the sMMSE, Severe Impairment Battery, Neuropsychiatric Inventory, and Disability Assessment for Dementia. Analysis of Variance and Analysis of Covariance models tested for treatment x disease severity interaction in the full MSAD study sample.

RESULTS

CIBIC-plus scores for donepezil patients were significantly improved compared with placebo for each time-point, with a 0.70 mean treatment difference at Week 24 last observation carried forward (LOCF; p = 0.0002). Significant differences favoring donepezil were noted at Week 24 LOCF for all secondary measures. There were no treatment x severity interactions for any of the efficacy measures.

CONCLUSIONS

In this analysis, donepezil had significant benefits over placebo on global, cognitive, functional, and behavioral measures in a subgroup of patients with more severe AD. Furthermore, the treatment effects of donepezil were not driven by a particular stratum within the moderate to severe dementia range.

Effect of donepezil in patients with Alzheimer's disease previously untreated or treated with memantine or nootropic agents in Germany: an observational study

OBJECTIVE

This open-label, prospective, observational, Post-Marketing Surveillance (PMS) study assessed the efficacy and safety of donepezil in patients who had been switched from therapies currently used in Germany to treat Alzheimer's disease (AD), such as memantine and nootropics, due to insufficient efficacy or poor tolerability. A treatment-naive population was included as a comparator.

RESEARCH DESIGN AND METHODS

Patients with AD were treated with donepezil and observed for a period of approximately 3 months. A cognitive assessment was made using the Mini-Mental State Examination (MMSE). Quality of life (QoL) was assessed by the investigators who answered the question 'How did therapy with donepezil influence the QoL of the patient and/or his family over the observation period?' and was graded using three ratings: improved/unchanged/worsened. Adverse events (AEs) were also monitored.

RESULTS

A total of 913 patients entered the study (mean +/- SD MMSE score 18.03 +/- 5.34). Efficacy assessments were analyzed for three groups: an overall group of patients who had received any form of prior AD drug therapy (N+ group; n = 709); a subgroup of patients from the N+ group who had received prior memantine therapy only (M+ group; n = 111) and patients who were drug treatment naive (N- group; n = 204). In the evaluable population donepezil improved MMSE scores by 2.21 +/- 3.47 points on average, with similar improvements observed in all three groups. QoL was judged to be improved in at least 70% of patients, again with similar results obtained for all three groups. Donepezil was well tolerated, with 85 of 913 (9.3%) patients reporting AEs. The most common AEs were those typically seen with cholinergic therapies (i.e., diarrhoea, vomiting and nausea).

CONCLUSIONS

In this observational PMS study, donepezil was shown to be efficacious and well tolerated in patients who were being insufficiently treated with memantine or nootropic therapy. The magnitude of response was similar to that observed in patients who were previously treatment naive, suggesting prior medication does not effect donepezil's efficacy.