Clinically meaningful treatment responses after switching to galantamine and with addition of memantine in patients with Alzheimer's disease receiving donepezil

Benefits and Harms of Prescription Drugs and Supplements for Treatment of Clinical Alzheimer-Type Dementia

BACKGROUND

Effects of drug treatment of clinical Alzheimer-type dementia (CATD) are uncertain.

PURPOSE

To summarize evidence on the effects of prescription drugs and supplements for CATD treatment.

DATA SOURCES

Electronic bibliographic databases (inception to November 2019), ClinicalTrials.gov (to November 2019), and systematic review bibliographies.

STUDY SELECTION

English-language trials of prescription drug and supplement treatment in older adults with CATD that report cognition, function, global measures, behavioral and psychological symptoms of dementia (BPSD), or harms. Minimum treatment was 24 weeks (≥2 weeks for selected BPSD).

DATA EXTRACTION

Studies with low or medium risk of bias (ROB) were analyzed. Two reviewers rated ROB. One reviewer extracted data; another verified extraction accuracy.

DATA SYNTHESIS

Fifty-five studies reporting non-BPSD outcomes (most ≤26 weeks) and 12 reporting BPSD (most ≤12 weeks) were analyzed. Across CATD severity, mostly low-strength evidence suggested that, compared with placebo, cholinesterase inhibitors produced small average improvements in cognition (median standardized mean difference [SMD], 0.30 [range, 0.24 to 0.52]), no difference to small improvement in function (median SMD, 0.19 [range, -0.10 to 0.22]), no difference in the likelihood of at least moderate improvement in global clinical impression (median absolute risk difference, 4% [range, 2% to 4%]), and increased withdrawals due to adverse events. In adults with moderate to severe CATD receiving cholinesterase inhibitors, low- to insufficient-strength evidence suggested that, compared with placebo, add-on memantine inconsistently improved cognition and improved global clinical impression but not function. Evidence was mostly insufficient about prescription drugs for BPSD and about supplements for all outcomes.

LIMITATION

Most drugs had few trials without high ROB, especially for supplements, active drug comparisons, BPSD, and longer trials.

CONCLUSION

Cholinesterase inhibitors and memantine slightly reduced short-term cognitive decline, and cholinesterase inhibitors slightly reduced reported functional decline, but differences versus placebo were of uncertain clinical importance. Evidence was mostly insufficient on drug treatment of BPSD and on supplements for all outcomes.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality. (PROSPERO: CRD42018117897).

Neuropsychiatric Symptoms in Dementia: Considerations for Pharmacotherapy in the USA

Dementia affects all domains of cognition. The relentless progression of the disease after diagnosis is associated with a 98% incidence of neuropsychiatric symptoms (NPS) at some point in the disease, including depression, psychosis, agitation, aggression, apathy, sleep disturbances, and disinhibition. These symptoms can be severe and lead to excess morbidity and mortality. The purpose of this article was to describe current literature on the medication management of NPS of dementia and highlight approaches to and concerns about the pharmacological treatment of NPS in the USA. Guidelines and expert opinion favor nonpharmacologic management of NPS as first-line management. Unfortunately, lack of adequate caregiver training and a high failure rate eventually result in the use of psychotropic agents in patients with dementia. Various psychotropic medications have been studied, although how they should be used in the management of NPS remains unclear. A systematic approach to evaluation, treatment, and monitoring, along with careful documentation and evidenced-based agent and dose selection, is likely to reduce risk and improve patient outcomes. Considerations should be given to the NPS presentation, including type, frequency, and severity, when weighing the risks and benefits of initiating, continuing, or discontinuing psychotropic management. Use of antidepressants, sedative/hypnotics, antipsychotics, and antiepileptic agents should include a clear and documented analysis of risk and benefit in a given patient with dementia.

Memantine for dementia

BACKGROUND

Memantine is a moderate affinity uncompetitive antagonist of glutamate NMDA receptors. It is licensed for use in moderate and severe Alzheimer's disease (AD); in the USA, it is also widely used off-label for mild AD.

OBJECTIVES

To determine efficacy and safety of memantine for people with dementia. To assess whether memantine adds benefit for people already taking cholinesterase inhibitors (ChEIs).

SEARCH METHODS

We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group's register of trials (http://www.medicine.ox.ac.uk/alois/) up to 25 March 2018. We examined clinical trials registries, press releases and posters of memantine manufacturers; and the web sites of the FDA, EMEA and NICE. We contacted authors and companies for missing information.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

We pooled and analysed data from four clinical domains across different aetiologies and severities of dementia and for AD with agitation. We assessed the impact of study duration, severity and concomitant use of ChEIs. Consequently, we restricted analyses to the licensed dose (20 mg/day or 28 mg extended release) and data at six to seven months duration of follow-up, and analysed separately results for mild and moderate-to-severe AD.We transformed results for efficacy outcomes into the difference in points on particular outcome scales.

MAIN RESULTS

Across all types of dementia, data were available from almost 10,000 participants in 44 included trials, most of which were at low or unclear risk of bias. For nearly half the studies, relevant data were obtained from unpublished sources. The majority of trials (29 in 7885 participants) were conducted in people with AD.1. Moderate-to-severe AD (with or without concomitant ChEIs). High-certainty evidence from up to 14 studies in around 3700 participants consistently shows a small clinical benefit for memantine versus placebo: clinical global rating (CGR): 0.21 CIBIC+ points (95% confidence interval (CI) 0.14 to 0.30); cognitive function (CF): 3.11 Severe Impairment Battery (SIB) points (95% CI 2.42 to 3.92); performance on activities of daily living (ADL): 1.09 ADL19 points (95% CI 0.62 to 1.64); and behaviour and mood (BM): 1.84 Neuropsychiatric Inventory (NPI) points (95% CI 1.05 to 2.76). There may be no difference in the number of people discontinuing memantine compared to placebo: risk ratio (RR) 0.93 (95% CI 0.83 to 1.04) corresponding to 13 fewer people per 1000 (95% CI 31 fewer to 7 more). Although there is moderate-certainty evidence that fewer people taking memantine experience agitation as an adverse event: RR 0.81 (95% CI 0.66 to 0.99) (25 fewer people per 1000, 95% CI 1 to 44 fewer), there is also moderate-certainty evidence, from three additional studies, suggesting that memantine is not beneficial as a treatment for agitation (e.g. Cohen Mansfield Agitation Inventory: clinical benefit of 0.50 CMAI points, 95% CI -3.71 to 4.71) .The presence of concomitant ChEI does not impact on the difference between memantine and placebo, with the possible exceptions of the BM outcome (larger effect in people taking ChEIs) and the CF outcome (smaller effect).2. Mild AD (Mini Mental State Examination (MMSE) 20 to 23): mainly moderate-certainty evidence based on post-hoc subgroups from up to four studies in around 600 participants suggests there is probably no difference between memantine and placebo for CF: 0.21 ADAS-Cog points (95% CI -0.95 to 1.38); performance on ADL: -0.07 ADL 23 points (95% CI -1.80 to 1.66); and BM: -0.29 NPI points (95% CI -2.16 to 1.58). There is less certainty in the CGR evidence, which also suggests there may be no difference: 0.09 CIBIC+ points (95% CI -0.12 to 0.30). Memantine (compared with placebo) may increase the numbers of people discontinuing treatment because of adverse events (RR 2.12, 95% CI 1.03 to 4.39).3. Mild-to-moderate vascular dementia. Moderate- and low-certainty evidence from two studies in around 750 participants indicates there is probably a small clinical benefit for CF: 2.15 ADAS-Cog points (95% CI 1.05 to 3.25); there may be a small clinical benefit for BM: 0.47 NOSGER disturbing behaviour points (95% CI 0.07 to 0.87); there is probably no difference in CGR: 0.03 CIBIC+ points (95% CI -0.28 to 0.34); and there may be no difference in ADL: 0.11 NOSGER II self-care subscale points (95% CI -0.35 to 0.54) or in the numbers of people discontinuing treatment: RR 1.05 (95% CI 0.83 to 1.34).There is limited, mainly low- or very low-certainty efficacy evidence for other types of dementia (Parkinson's disease and dementia Lewy bodies (for which CGR may show a small clinical benefit; four studies in 319 people); frontotemporal dementia (two studies in 133 people); and AIDS-related Dementia Complex (one study in 140 people)).There is high-certainty evidence showing no difference between memantine and placebo in the proportion experiencing at least one adverse event: RR 1.03 (95% CI 1.00 to 1.06); the RR does not differ between aetiologies or severities of dementia. Combining available data from all trials, there is moderate-certainty evidence that memantine is 1.6 times more likely than placebo to result in dizziness (6.1% versus 3.9%), low-certainty evidence of a 1.3-fold increased risk of headache (5.5% versus 4.3%), but high-certainty evidence of no difference in falls.

AUTHORS' CONCLUSIONS

We found important differences in the efficacy of memantine in mild AD compared to that in moderate-to-severe AD. There is a small clinical benefit of memantine in people with moderate-to-severe AD, which occurs irrespective of whether they are also taking a ChEI, but no benefit in people with mild AD.Clinical heterogeneity in AD makes it unlikely that any single drug will have a large effect size, and means that the optimal drug treatment may involve multiple drugs, each having an effect size that may be less than the minimum clinically important difference.A definitive long-duration trial in mild AD is needed to establish whether starting memantine earlier would be beneficial over the long term and safe: at present the evidence is against this, despite it being common practice. A long-duration trial in moderate-to-severe AD is needed to establish whether the benefit persists beyond six months.

Galantamine Response Associates with Agitation and the Prefrontal Cortex in Patients with Alzheimer's Disease

Behavioral and psychological symptoms of dementia (BPSD) occur in up to 80% of AD patients and represent one of the largest factors contributing to caregiver burden. To analyze the effect of galantamine on BPSD and caregiver burden, we treated a total of 50 patients with mild AD for 12 weeks and evaluated them using the Neuropsychiatric Inventory (NPI) and Japanese version of the Zarit Caregiver Burden Interview (ZBI). We also performed regional cerebral blood flow single photon emission computed tomography (rCBF SPECT) at baseline using three-dimensional sterotatic surface projections. Total NPI and ZBI scores did not significantly change after 12-week galantamine treatment. To identify the characteristics of patients who showed improvement after galantamine treatment, we divided patients into two groups, those with and those without sub-items on the NPI. Patients with aggression showed improvement in ZBI scores (p < 0.05). A comparison of rCBF SPECT between these two groups indicated that patients with aggression exhibited increased rCBF in the right prefrontal cortex compared with those without aggression. In a patient with aggression, 20-month treatment with galantamine inhibited increases in the rCBF area in the right prefrontal lobe. These results suggest that galantamine response may be related to aggression and dysfunction of the prefrontal cortex.

Treatment effects between monotherapy of donepezil versus combination with memantine for Alzheimer disease: A meta-analysis

BACKGROUND

This is the first meta-analysis to compare the treatment effects and safety of administering donepezil alone versus a combination of memantine and donepezil to treat patients with moderate to severe Alzheimer Disease, particularly regarding cognitive functions, behavioral and psychological symptoms in dementia (BPSD), and global functions.

METHODS

PubMed, Medline, Embase, PsycINFO, and Cochrane databases were used to search for English and non-English articles for inclusion in the meta-analysis to evaluate the effect size and incidence of adverse drug reactions of different treatments.

RESULTS

Compared with patients who received donepezil alone, those who received donepezil in combination with memantine exhibited limited improvements in cognitive functions (g = 0.378, p < .001), BPSD (g = -0.878, p < .001) and global functions (g = -0.585, p = .004). Gradual titration of memantine plus a fixed dose and gradual titration of donepezil as well as a fixed dose and gradual titration of memantine resulted in limited improvements in cognitive functions(g = 0.371, p = .005), BPSD(g = -0.913, p = .001), and global functions(g = -0.371, p = .001).

CONCLUSION

Both in the 24th week and at the final evaluation point, the combination of donepezil and memantine led to greater improvement in cognitive functions, BPSD, and global functions than did donepezil alone in patients with moderate to severe Alzheimer Disease.

Predicting the neural effect of switching from donepezil to galantamine based on single-photon emission computed tomography findings in patients with Alzheimer's disease

BACKGROUND

A number of neuroimaging studies have addressed the specific effect of treatment with cholinesterase inhibitors on the frontal lobe in patients with Alzheimer's disease (AD). However, the neural effects of cholinesterase inhibitors on both apathy and executive dysfunction remain unclear. We examined whether baseline regional cerebral blood flow, as determined by using single-photon emission computed tomography, is capable of predicting changes in apathy and executive dysfunction in response to AD patients switching from donepezil to galantamine therapy.

METHODS

We conducted a 24-week, prospective, open-label study of AD patients treated with galantamine who did not respond to previous treatment with donepezil. Single-photon emission computed tomography was performed at baseline, and behaviour and cognitive assessments including the Mini-Mental State Examination, the Japanese version of the Alzheimer's Disease Assessment Scale-cognitive subscale, the Frontal Assessment Battery, the Neuropsychiatry Inventory Brief Questionnaire Form, and the Dysexecutive Questionnaire were conducted at three time points (baseline and after 12 and 24 weeks of galantamine therapy).

RESULTS

After galantamine therapy, the Neuropsychiatry Inventory Brief Questionnaire Form scores (apathy, irritability, and aberrant motor symptoms) and the Dysexecutive Questionnaire score improved significantly. The single-photon emission computed tomography findings showed that lower baseline regional cerebral blood flow values in several frontal areas, including the dorsolateral and ventrolateral prefrontal cortex, the anterior cingulate, and the orbitofrontal cortex, predicted greater reductions in the score for apathy (distress) on the Neuropsychiatry Inventory Brief Questionnaire Form and the Dysexecutive Questionnaire score after patients switched from donepezil to galantamine therapy.

CONCLUSIONS

Our study suggests that galantamine therapy, unlike donepezil, is characterized by a dual mechanism of action that may increase acetylcholine and the nicotinic receptor-modulation effect within the frontal lobe, both of which are associated with apathy and executive dysfunction in AD patients.

Benefits and risks of add-on therapies for Alzheimer's disease

Despite three decades of intensive research, the efforts of scientific society and industry and the expenditures, numerous attempts to develop effective treatments for Alzheimer's disease have failed. Currently, approved and widely used medications to treat cognitive deficits in Alzheimer's disease are symptomatic only and show at best modest efficacy. In this context, the need to develop a successful, disease-modifying treatment is loudly expressed. One way to achieve this goal is the use of add-on therapies or various combinations of existing ‘conventional’ drugs. Results of several clinical studies and post hoc analyses of combination therapy with all cholinesterase inhibitors and memantine are published. Moreover, there is a need for studies on long-term efficacy of combination therapy in Alzheimer's.

Differential effects of acetylcholinesterase inhibitors on clinical responses and cerebral blood flow changes in patients with Alzheimer's disease: a 12-month, randomized, and open-label trial

BACKGROUND/AIMS

The present study evaluated the differences in treatment outcomes and brain perfusion changes among 3 types of acetylcholinesterase inhibitors (AchEIs, i.e. donepezil, rivastigmine, and galantamine).

METHODS

This was a prospective, longitudinal, randomized, open-label, 3-arm (donepezil, rivastigmine, or galantamine), parallel-group, 12-month clinical trial carried out in 55 patients with AD.

RESULTS

At 6 months, the results of the Mini-Mental State Examination (MMSE) and the Trail Making Test (TMT)-Part A showed an improvement versus baseline in the donepezil treatment group. All groups showed a significant increase in regional cerebral blood flow (rCBF), mainly in the frontal lobe. Significant rCBF reduction was observed in the temporal lobe and cingulate gyrus in all 3 groups.

CONCLUSION

AchEI treatment prevents the progression of cognitive impairment and increases the relative rCBF in the frontal lobe.

AlzPlatform: an Alzheimer's disease domain-specific chemogenomics knowledgebase for polypharmacology and target identification research

Alzheimer’s disease (AD) is one of the most complicated progressive neurodegeneration diseases that involve many genes, proteins, and their complex interactions. No effective medicines or treatments are available yet to stop or reverse the progression of the disease due to its polygenic nature. To facilitate discovery of new AD drugs and better understand the AD neurosignaling pathways involved, we have constructed an Alzheimer’s disease domain-specific chemogenomics knowledgebase, AlzPlatform (www.cbligand.org/AD/) with cloud computing and sourcing functions. AlzPlatform is implemented with powerful computational algorithms, including our established TargetHunter, HTDocking, and BBB Predictor for target identification and polypharmacology analysis for AD research. The platform has assembled various AD-related chemogenomics data records, including 928 genes and 320 proteins related to AD, 194 AD drugs approved or in clinical trials, and 405 188 chemicals associated with 1 023 137 records of reported bioactivities from 38 284 corresponding bioassays and 10 050 references. Furthermore, we have demonstrated the application of the AlzPlatform in three case studies for identification of multitargets and polypharmacology analysis of FDA-approved drugs and also for screening and prediction of new AD active small chemical molecules and potential novel AD drug targets by our established TargetHunter and/or HTDocking programs. The predictions were confirmed by reported bioactivity data and our in vitro experimental validation. Overall, AlzPlatform will enrich our knowledge for AD target identification, drug discovery, and polypharmacology analyses and, also, facilitate the chemogenomics data sharing and information exchange/communications in aid of new anti-AD drug discovery and development.

Dysfunctional synapse in Alzheimer's disease - A focus on NMDA receptors

Alzheimer's disease (AD) is the most prevalent form of dementia in the elderly. Alterations capable of causing brain circuitry dysfunctions in AD may take several years to develop. Oligomeric amyloid-beta peptide (Aβ) plays a complex role in the molecular events that lead to progressive loss of function and eventually to neurodegeneration in this devastating disease. Moreover, N-methyl-D-aspartate (NMDA) receptors (NMDARs) activation has been recently implicated in AD-related synaptic dysfunction. Thus, in this review we focus on glutamatergic neurotransmission impairment and the changes in NMDAR regulation in AD, following the description on the role and location of NMDARs at pre- and post-synaptic sites under physiological conditions. In addition, considering that there is currently no effective ways to cure AD or stop its progression, we further discuss the relevance of NMDARs antagonists to prevent AD symptomatology. This review posits additional information on the role played by Aβ in AD and the importance of targeting the tripartite glutamatergic synapse in early asymptomatic and possible reversible stages of the disease through preventive and/or disease-modifying therapeutic strategies. This article is part of the Special Issue entitled 'The Synaptic Basis of Neurodegenerative Disorders'.

Domperidone effective in preventing rivastigmine-related gastrointestinal disturbances in patients with Alzheimer's disease

OBJECTIVE

While acetylcholinesterase inhibitors, such as donepezil, galantamine, and rivastig-mine, are beneficial in treating behavioral symptoms of patients with Alzheimer's disease (AD), their dose-limiting effects include gastrointestinal disturbances, such as nausea, vomiting, and diarrhea. We aimed to predict the occurrence of these gastrointestinal disturbances with rivastigmine therapy for optimal drug choice and improved compliance.

MATERIALS AND METHODS

Thirty patients with mild-to-moderate AD (scores 10-22 on the MiniMental State Examination) were administered a rivastigmine 18 mg patch with domperidone 30 mg (RWD) and without domperidone (RWOD; n = 15 each) for 20 weeks. Gastrointestinal disturbances were evaluated using a frequency scale for symptoms of gastroesophageal reflux disease (FSSG), Bristol stool form scale, laboratory data (hemoglobin, albumin, total cholesterol), body weight, and amount of food intake.

RESULTS

After 12 weeks, FSSG scores were higher in the RWOD group compared to baseline scores; however, no significant differences were noted between the RWD and RWOD groups. We then subdivided each group based on high and low baseline scores; the RWOD high-score (≥4) subgroup showed increased FSSG after 12 weeks compared with the baseline score. In both RWD and RWOD groups, the low-score (≤3) subgroups showed no changes during the dose-escalation phase.

CONCLUSION

For AD patients with higher FSSG scores at baseline, domperidone was effective in preventing rivastigmine-related gastrointestinal disturbances.