Richard Zhang

Pfizer Inc., New York City, New York, United States

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Publications (20)114.07 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: 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. 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. 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. 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.
    Trials 10/2011; 12:233. · 2.12 Impact Factor
    This article is viewable in ResearchGate's enriched format
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    ABSTRACT: To determine whether donepezil treatment (10 mg/day over 24 weeks) is associated with delayed emergence of apathy in patients with mild to moderate Alzheimer's disease (AD) and to explore relationships between donepezil's effects on apathy and other Neuropsychiatric Inventory (NPI)-measured behavioural symptoms. Two randomised, double-blind, parallel-group, placebo-controlled studies that met prespecified criteria and were sufficiently similar to allow data pooling were derived from all donepezil AD clinical trials. Patients scoring from 10 to 26 on baseline Mini-Mental Status Examination were included. A clinical milestone for apathy and other NPI items was defined as the first emergence of a composite score (frequency × severity) ≥ 3. Differences in time to event (i.e. milestone) between donepezil- and placebo-treated groups were assessed using the Kaplan-Meier method and log-rank test. Shift tables were constructed to evaluate clinical milestone status for apathy and other NPI items at baseline and endpoint, and were analysed using the Cochran-Mantel-Haenszel (CMH) test, stratified by baseline status. Of all NPI items, apathy had the highest proportion of subjects scoring ≥ 3 at baseline. Donepezil was superior to placebo on both apathy milestone analyses (time-to-event log-rank test and shift table CMH test, p = 0.01). Aberrant motor behaviour demonstrated similar benefit. Donepezil treatment appears to have resulted in a significant reduction over 6 months of the emergence of apathy in patients with AD. These data suggest that a prospective clinical trial in patients with early AD that includes apathy as a primary outcome measure may be warranted.
    International Journal of Geriatric Psychiatry 02/2011; 26(2):150-7. · 3.09 Impact Factor
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    ABSTRACT: The objective of this 10-week, randomized, double-blind, placebo-controlled multicenter study was to assess the efficacy and safety of donepezil for the treatment of cognitive dysfunction exhibited by children with Down syndrome (DS). Intervention comprised donepezil (2.5-10 mg/day) in children (aged 10-17 years) with DS of mild-to-moderate severity. The primary measures were the Vineland-II Adaptive Behavior Scales (VABS-II) Parent/Caregiver Rating Form (PCRF) the sum of nine subdomain standardized scores and standard safety measures. Secondary measures included the VABS-II/PCRF scores on the following domains and their respective individual subdomains: Communication (receptive, expressive, and written); Daily Living Skills (personal, domestic, and community); Socialization (interpersonal relationships, play and leisure time, and coping skills), and scores on the Test of Verbal Expression and Reasoning, a subject-performance-based measure of expressive language. At baseline, 129 participants were assigned treatment with donepezil or placebo. During the double-blind phase, VABS II/PCRF sum of the nine subdomain standardized scores, called v-scores, improved significantly from baseline in both groups (P < 0.0001), with no significant between-group differences. This trial failed to demonstrate any benefit for donepezil versus placebo in children and adolescents with DS, although donepezil appeared to be well tolerated.
    American Journal of Medical Genetics Part A 12/2010; 152A(12):3028-35. · 2.30 Impact Factor
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    ABSTRACT: 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. 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. 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. 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.
    Alzheimer's & dementia: the journal of the Alzheimer's Association 11/2010; 6(6):431-9. · 14.48 Impact Factor
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    ABSTRACT: We aimed to develop a standardization method to pool data recorded on different activities of daily living (ADL) scales in order to reduce variability of functional outcome data from Alzheimer's disease (AD) clinical trials and to better evaluate the effect of donepezil treatment on function in patients with AD. Based on pre-specified criteria, six studies were selected from among all donepezil clinical trials in AD. Individual items from nine ADL scales used in these trials were mapped to a standardized functional scale comprising 12 domains (six basic, six instrumental); scores were transformed to a 0-100 scale. External validation of this scale yielded a concordance rate of 90.8%. For each domain, mean change from baseline to 24 weeks in the placebo and donepezil groups was compared for the total population and for subgroups stratified by baseline disease severity. Study settings included outpatient, assisted living, and skilled nursing facilities. Participants comprised 2183 patients (donepezil, 1261; placebo; 922) with baseline Mini-mental State Examination (MMSE) scores 5-26. Significant treatment differences favoring donepezil were observed for five items (two instrumental and three basic). Patients with moderate AD at baseline (MMSE 10-17) demonstrated the greatest treatment effect. Functional data were successfully pooled using standardizing methodology. A beneficial effect of donepezil treatment on function was demonstrated using this standardized functional scale. Similar analyses from studies with other anti-dementia drugs may help to determine the generalizability of these findings and potentially encourage use of functional assessment as a clinical tool.
    International Psychogeriatrics 09/2010; 22(6):973-83. · 1.89 Impact Factor
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    ABSTRACT: To better characterize response to donepezil in patients with severe AD, Severe Impairment Battery (SIB) data were pooled from four donepezil clinical trials (N=904). Changes in SIB total and domain scores from baseline to week 24 were compared between placebo and donepezil treatment groups (observed case analysis). Analyses were stratified by baseline severity (Mini-Mental State Examination [MMSE] scores 1-5, 6-9, 10-12 and 13-17) to allow investigation of responses at different stages of cognitive impairment. Relationships to global and functional measures were explored. The difference between donepezil- and placebo-treated patients in least squares (LS) mean change in SIB total scores from baseline to week 24 was 6.22 (p < 0.0001, Cohen's d, 0.53). Treatment-placebo differences were statistically significant for each baseline severity stratum, being greatest for the MMSE 6-9 stratum (LS mean difference, 7.60; p < 0.0001, Cohen's d, 0.66). Treatment-placebo differences in LS mean change in SIB domain scores significantly favored donepezil for seven of nine domains (range, p = 0.0056 to p < 0.0001; Cohen's d, 0.17-0.48). Change in total SIB score correlated significantly with change in measures of activities of daily living and global status. These results indicate that donepezil provides cognitive benefits in patients with severe AD, including those most markedly impaired. The treatment effect size and correlation between improvements in SIB scores and functional and global outcome measures suggest the drug-placebo differences are clinically meaningful.
    Journal of Alzheimer's disease: JAD 01/2010; 21(3):843-51. · 3.61 Impact Factor
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    ABSTRACT: 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.
    Alzheimer disease and associated disorders 07/2009; 23(4):357-64. · 2.88 Impact Factor
  • Alzheimer's and Dementia 07/2008; 4(4). · 17.47 Impact Factor
  • Alzheimer's and Dementia 07/2008; 4(4). · 17.47 Impact Factor
  • Alzheimer's and Dementia 07/2008; 4(4). · 17.47 Impact Factor
  • Journal of the American Medical Directors Association 03/2008; 9(3). · 4.78 Impact Factor
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    ABSTRACT: 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. To evaluate the safety and tolerability of donepezil at doses of 15 and 20 mg/day. 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. 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. 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.
    Drugs & Aging 02/2008; 25(2):163-74. · 2.50 Impact Factor
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    ABSTRACT: 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. 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. 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. The results of these analyses suggest that donepezil reduces behavioral symptoms, particularly mood disturbances and delusions, in patients with AD with relatively severe psychopathology.
    American Journal of Geriatric Psychiatry 08/2006; 14(7):605-12. · 3.52 Impact Factor
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    ABSTRACT: To assess the impact of donepezil treatment compared with placebo on caregiver time spent assisting patients with Alzheimer's disease (AD). Patient and caregiver data were collected as part of a 1-year, prospective, double-blind, randomized, placebo-controlled trial. The Resource Utilization in Dementia (RUD) questionnaire was used to record caregiver time at study baseline and at Weeks 12, 24, 36, and 52. This analysis focuses solely on those caregivers who were actively (> 0 h/day reported on the RUD) providing care at study baseline. The change in time relative to baseline that caregivers spent assisting patients over the course of the study. The active caregiver population was composed of 96 caregivers of donepezil-treated patients and 94 caregivers of patients receiving placebo. Over the course of the 1-year study, and as the condition of the AD patients deteriorated, it was expected that caregiver time would increase. As expected, after 52 weeks, caregivers of placebo patients were providing almost 2 h each day (106.8 min) more care than they had done at study baseline. For those caregivers of donepezil-treated patients, although they were spending more time caring than they had done at study baseline, their time burden had only increased by 42.6 min more each day. This difference in caring time between the 2 groups, relative to baseline at Week 52, was 1.1 h (64.2 min) each day, and was significant (p = 0.03). Caregiver time devoted to helping an AD patient typically increases with the severity of the disease. By helping the patient maintain his/her ability to perform activities of daily living for longer, treatment with donepezil is not only beneficial to the patient, but also has positive time-burden implications for the caregiver.
    Current Medical Research and Opinion 08/2004; 20(8):1221-5. · 2.37 Impact Factor
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    ABSTRACT: Donepezil has consistently been shown to be effective and well tolerated in the symptomatic treatment of Alzheimer's disease in placebo-controlled clinical trials. It has been shown to provide significant benefits in cognition, global function and activities of daily living in patients with mild-to-moderate Alzheimer's disease. However, in order to control for confounding factors, some clinical trials of donepezil have excluded patients with comorbid illness and concomitant medication use. The objective of this study was to evaluate the efficacy, tolerability and safety of donepezil in a wider and more diverse sample of patients and centres than previous trials, reflecting routine clinical practice. In this 12-week, open-label, multicentre trial, patients with probable mild-to-moderate Alzheimer's disease received donepezil 5 mg/day for 28 days, after which the dosage was increased to 10 mg/day according to the investigating clinician's judgement. Patients were enrolled at 246 study centres in 18 countries worldwide. Cognition was assessed by a trained clinician using the Mini-Mental State Examination (MMSE) at baseline, week 4 and week 12 (or last visit). Changes in patient activity and social interaction were evaluated using a caregiver diary. Each week, caregivers recorded their impression of change compared with baseline on three aspects of patient behaviour using a 5-point scale. Efficacy analyses were performed on the intent-to-treat population. Significance was determined using the paired t-test (0.05 significance level). Tolerability and safety were assessed by monitoring adverse events, physical examinations, vital signs, clinical laboratory test abnormalities and ECG findings throughout the study. A total of 1113 patients received donepezil (mean baseline MMSE score [+/-SD] 18.74 +/- 5.21). 989 (88.9%) patients completed the study; 59 (5%) patients discontinued because of adverse events. Most patients were taking at least one concomitant medication (n = 802; 72%) and had at least one comorbid medical condition (n = 745; 67%) on study entry. Donepezil significantly improved cognition compared with baseline at weeks 4 and 12, and at week 12 using a last observation carried forward (LOCF) analysis (all p < 0.0001). Mean change from baseline MMSE score (+/-SE) at week 12-LOCF was +1.73 +/- 0.10. Donepezil was also associated with significant improvements in patient social interaction, engagement and interest, and initiation of pleasurable activities at all weekly assessments and week 12-LOCF (all p < 0.0001). Donepezil was generally well tolerated; adverse events were consistent with the known safety profile of donepezil. Donepezil treatment resulted in statistically significant improvements in cognition and patient activity and social behaviour, and was generally well tolerated despite high levels of comorbid illness and concomitant medication use. The results of this open-label study in a large patient population are consistent with those from controlled trials and support that donepezil is effective in the treatment of mild-to-moderate Alzheimer's disease in everyday practice.
    Drugs & Aging 02/2004; 21(1):43-53. · 2.50 Impact Factor
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    ABSTRACT: To compare directly, in the same patient cohort, the ease of use and tolerability of donepezil and galantamine in the treatment of Alzheimer's disease (AD), and investigate the effects of both treatments on cognition and activities of daily living (ADL). Patients with mild to moderate AD from 14 European centres were randomised to receive open-label donepezil (up to 10 mg once daily) or galantamine (up to 12 mg twice daily) for 12 weeks, according to the approved product labelling. Physicians and caregivers completed questionnaires rating satisfaction with treatment/ease of use in daily practice. Secondary assessments were the ADAS-cog, the MMSE, and the DAD scale to assess ADL. Tolerability was evaluated by reporting adverse events (AEs). Both physicians and caregivers reported significantly greater overall satisfaction/ease of use for donepezil (n = 64) compared with galantamine (n = 56) at weeks 4, 12, and endpoint (week 12 LOCF; all p-values <0.05). Significantly greater improvements in cognition were also observed for donepezil versus galantamine on the ADAS-cog at Week 12 and endpoint (p-values <0.05). ADL improved significantly in the donepezil group compared with the galantamine group at weeks 4, 12, and endpoint (p-values <0.05). Most AEs were mild to moderate, however, 46% galantamine-treated patients reported gastrointestinal AEs vs 25% donepezil patients. Physician and caregiver ease of use/satisfaction scores, and assessments of cognition and ADL, showed significant benefits for donepezil compared with galantamine in this direct comparative trial. Both treatments were well tolerated, with more gastrointestinal AEs reported for galantamine vs donepezil.
    International Journal of Geriatric Psychiatry 02/2004; 19(1):58-67. · 3.09 Impact Factor
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    ABSTRACT: The costs and consequences of donepezil versus placebo treatment in patients with mild to moderate Alzheimer's disease (AD) were evaluated as part of a 1-year prospective, double-blind, randomized, multinational clinical trial. Patients received either donepezil (n = 142; 5 mg/day for 28 days followed by 10 mg/day according to the clinician's judgement) or placebo (n = 144). Unit costs were assessed in 1999 Swedish kronas (SEK) and converted to US dollars (USD). Donepezil-treated patients gained functional benefits relative to placebo on the Progressive Deterioration Scale (p = 0.042) and Instrumental Activities of Daily Living scale (p = 0.025) at week 52. Caregivers of donepezil-treated patients spent an average of 400 h less annually providing care than caregivers of placebo-treated patients. Mean annual healthcare costs were SEK 137,752 (USD 16,438) per patient for the donepezil group and SEK 135,314 (USD 16,147) in the placebo group. With the average annual cost of donepezil at SEK 10,723 (USD 1,280) per patient, the SEK 2,438 (USD 291) cost difference represented a 77% cost offset. When caregiver time and healthcare costs were included, mean annual costs were SEK 209,244 (USD 24,969) per patient in the donepezil group and SEK 218,434 (USD 26,066) in the placebo group, a total saving associated with donepezil treatment of SEK 9,190 (USD 1,097) per patient [95% CI of SEK -43,959 (USD -5,246), SEK 25,581 (USD 3,053); p = 0.6]. The positive effects on the efficacy outcome measures combined with no additional costs from a societal perspective indicate that donepezil is a cost-effective treatment, representing an improved strategy for the management of patients with AD.
    Dementia and Geriatric Cognitive Disorders 02/2003; 15(1):44-54. · 2.81 Impact Factor
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    ABSTRACT: The results of this 1-year, multinational, double-blind, placebo-controlled study of an acetylcholinesterase inhibitor confirm the beneficial effects of donepezil on cognition, activities of daily living and behavioral symptoms over 1 year in the treatment of patients with mild to moderate Alzheimer's disease. Indeed, the data are consistent with those from the previously reported pivotal studies that led to the widespread marketing approval of donepezil. Data suggest that to maximize the benefits of donepezil, treatment should begin as early as possible, ideally in patients with mild Alzheimer's disease. Further, the determination of the benefits of therapy should be made by the physician and caregiver in conjunction with the patient, if possible, on the basis of improvement, stabilization, or a slowing of the deterioration in symptoms in any of the three areas commonly affected with Alzheimer's disease: cognition activity of daily living and behavior.
    Alzheimer's Disease: Advances in Etiology, Pathogenesis and Therapeutics, 04/2002: pages 725 - 738; , ISBN: 9780470846452
  • Neurobiology of Aging 05/2000; 21:160-161. · 4.85 Impact Factor
  • Neurobiology of Aging 05/2000; 21:274-274. · 4.85 Impact Factor

Publication Stats

348 Citations
114.07 Total Impact Points


  • 2002–2010
    • Pfizer Inc.
      • Pfizer Pharmaceuticals Group
      New York City, New York, United States
  • 2009
    • Royal United Hospital Bath NHS Trust
      Bath, England, United Kingdom
  • 2003
    • Umeå University
      Umeå, Västerbotten, Sweden