To evaluate the feasibility of longitudinal assessment and the psychometric properties of both established and new outcome measures used in clinical trials of patients with dementia in a cohort of Spanish-speaking elders in the United States.
This is a prospectively collected multicenter study comparing patients with Alzheimer disease (AD) (N = 77) and elderly controls (N = 17) who are primary Spanish speakers. Spanish-speaking individuals with AD (SSI AD) were selected to represent predefined categories of impairment as determined by a Mini-Mental State Examination score. Controls were selected to approximately match by age and education (SSI C). Subjects were administered a series of Spanish translations of established outcome measures (Mini-Mental State Examination, Clinical Dementia Rating, Geriatric Dementia Scale), and Functional Assessment Staging (FAST)] and new outcome measures developed for United States in clinical trials to assess cognition, function, behavioral disturbance, and clinical global change. Half of the subjects were assessed at 1 and 2 months to evaluate reliability; all subjects were assessed at 6 and 12 months. Comparisons were made between patients and controls and between the Spanish-speaking cohort and a similar English-speaking cohort.
The 12-month completion rate was 77%, with a trend toward greater impairment in those with full retention. Both established and new measures demonstrated good internal consistency and test-retest reliability in this cohort. All but one measure of cognition demonstrated excellent discriminability between AD subjects and controls. The SSI AD cohort declined significantly on measures of cognition, function, and clinical global change over the 12-month assessment period. The SSI AD and English AD (ESI AD) cohorts declined equivalently on the most common outcomes in clinical trials of AD (delayed recall, clinical global change). Likewise, the most common behavioral changes were also similar in the ESI and SSI groups. However, the annual change was lower in SSI AD than in the ESI AD on several other measures of cognition and function.
These results support the recruitment of Spanish-speaking patients and the use of Spanish language translations for use in the clinical trials for AD.
Alzheimer disease; Spanish language assessment; outcome measures; clinical trials
The Prevention Instrument project of the Alzheimer’s Disease Cooperative Study (ADCS) seeks to develop instruments to assess treatment efficacy including potential economic benefit. The Resource Use Inventory (RUI) is an instrument that has been used to capture resource utilization and costs in populations with Alzheimer disease (AD). However, resource utilization and costs for healthy, cognitively intact elderly as they begin to demonstrate cognitive deterioration are not well understood. In addition, the loss that relates to the subjects’ own time as they transition through cognitive impairment is not well documented.
To evaluate the utility of the RUI in a sample of cognitively intact elderly individuals living in the community and enrolled in AD prevention trials.
The RUI was administered to 644 subjects and their study partners either at home or in the clinic. For half of each sample, 3-month retesting was carried out. The RUI consisted of 9 questions. The first part of the RUI captured subjects’ use of direct medical care (eg, hospitalizations) and nonmedical care (eg, home health aides). The second part of the RUI captured the time caregivers spend providing care to the subjects. The third part of the RUI captured subjects’ participation in volunteer work and employment. The assessment interval for each question was the past 3 months.
The percentage of RUI forms returned incomplete or inaccurate for both in-clinic and at-home groups was extremely low. There were no differences in utilization rates between in-clinic and at-home group for all items in the RUI. Except for use of outpatient procedures, tests, or treatments, there were no differences in utilization rates between subjects who filled out the RUI with the help of their study partners or by themselves. Items in the RUI were sensitive to subjects’ cognitive and functional status and demographic characteristics.
Home-based completion of the RUI by participants in an AD prevention study is feasible, and seems to provide data that are reliable and valid. The instrument will be useful for tracking resource and time use through transition from healthy to cognitive impairment.
Alzheimer disease; primary prevention; assessment measure; resource use; health care utilization; clinical trials
Mild cognitive impairment (MCI) is a transitional state between normal cognitive functioning and dementia. A proposed MCI typology1 classifies individuals by the type and extent of cognitive impairment, yet few studies have characterized or compared these subtypes. 447 women 65 years of age and older from the Women’s Health Initiative Memory Study2 were classified into the four MCI subgroups and a ‘no impairment’ group and compared on clinical, sociodemographic, and health variables.
82.1% of participants had a cognitive deficit in at least one domain with most (74.3%) having deficits in multiple cognitive domains. Only 4.3% had an isolated memory deficit, while 21.3% had an isolated non-memory deficit. Of the 112 women who met all MCI criteria examined, the most common subtype was amnestic multi-domain MCI (42.8%) followed by non-amnestic multiple domain MCI (26.7%), non-amnestic single domain (24.1%) and amnestic single domain MCI (6.3%). Subtypes were similar with respect to education, health status, smoking, depression and pre- and on-study use of hormone therapy.
Despite the attention it receives in the literature amnestic MCI is the least common type highlighting the importance of identifying and characterizing other non-amnestic and multi-domain subtypes. Further research is needed on the epidemiology of MCI subtypes, clinical and biological differences between them and rates for conversion to dementia.
MCI; women; WHIMS; postmenopausal; cognition; dementia; hormone therapy
We applied the hippocampal radial atrophy mapping technique to the baseline and follow-up magnetic resonance image data of 169 amnestic mild cognitive impairment (MCI) participants in the imaging arm of the Alzheimer's Disease Cooperative Study MCI Donepezil/Vitamin E trial. Sixty percent of the subjects with none to mild hippocampal atrophy rated with the visual medial temporal atrophy rating scale (MTA score < 2) and 33.8% of the subjects with moderate to severe (MTA ≥ 2) hippocampal atrophy converted to Alzheimer's disease (AD) during 3-year follow-up. MTA ≥ 2 showed a trend for greater left sided hippocampal atrophy versus MTA < 2 groups at baseline (Pcorrected = 0.08). Higher MTA scores were associated with progressive atrophy of the subiculum and the CA1–3 subregions. The MTA < 2 group demonstrated significant bilateral atrophy progression at follow-up (left Pcorrected = 0.008; right Pcorrected = 0.05). Relative to MTA < 2 nonconverters, MTA < 2 converters showed further involvement of the subiculum and CA1 and additional involvement of CA2–3 at follow-up. Right CA1 atrophy was significantly associated with conversion to dementia (for 1 mm greater right CA1 radial distance subjects had 50% reduced hazard for conversion). Greater CA1 and subicular atrophy can be demonstrated early and is predictive of future conversion to AD, whereas CA2–3 involvement becomes more evident as the disease progresses.
mild cognitive impairment; conversion; hippocampal atrophy; medial temporal atrophy; magnetic resonance imaging; imaging biomarker
Cognitive-discrepancy analysis has been shown to be a useful technique for detecting subtle cognitive deficits in normal-functioning elderly individuals who are genetically at-risk for Alzheimer disease (AD). However, studies that have used cognitive-discrepancy measures to date have used retrospective or cross-sectional designs, and the utility of this approach to predict cognitive decline has not been examined in a prospective investigation.
San Diego, CA, Veterans Administration Hospital.
Twenty-four normal-functioning elderly individuals participated in the study, with 16 subjects exhibiting no change in their Dementia Rating Scale (DRS) scores over an 1-year period (Stable Group), and 8 subjects exhibiting a decline in DRS scores over the 1-year period (Decline group).
A cognitive-discrepancy measure isolating cognitive switching was computed that contrasted performance on a new higher-level task of executive functioning (a Stroop/Switching measure) relative to a composite measure of lower-level Stroop conditions.
a) In the year before their cognitive changes, the Decline group exhibited a significantly larger cognitive-discrepancy (Stroop/Switching versus lower-level Stroop conditions) score compared with a control (Stable) group; and b) the cognitive-discrepancy measure was superior to APOE genotype in predicting DRS decline.
Cognitive-discrepancy analysis isolating a component executive function ability not only seems to be a useful tool for identifying individuals at risk for cognitive deficits, but also shows promise in predicting individuals who may show subtle cognitive decline over time.
Cognitive discrepancies; aging; Alzheimer disease; executive functioning
White matter hyperintensities (WMH) have an effect on cognition and are increased in severity among individuals with amnestic mild cognitive impairment (aMCI). The influence of WMH on progression of aMCI to Alzheimer’s disease (AD) is less clear.
Data were drawn from a three-year prospective, double blind, placebo controlled clinical trial that examined the effect of donepezil or vitamin E on progression from aMCI to AD. WMH from multiple brain regions were scored on MR images obtained at entry into the trial from a subset of 152 study participants using a standardized visual rating scale. Cox proportional hazards models adjusting for age, education and treatment arm were used to investigate the role of WMH on time to progression.
55 of the 152 (36.2 %) aMCI subjects progressed to AD. Only periventricular hyperintensities (PVH) were related to an increased risk of AD within three years (HR = 1.59, 95 % CI = 1.24–2.05, p-value < 0.001). Correcting for medial temporal lobe atrophy or the presence of lacunes did not change statistical significance.
PVH are associated with an increased risk of progression from aMCI to AD. This suggests that PVH, an MRI finding thought to represent cerebrovascular damage, contributes to AD onset in vulnerable individuals independent of Alzheimer pathology.
Alzheimer’s disease; MCI (mild cognitive impairment); MRI; cerebrovascular disease
Dementia with Lewy Bodies (DLB) is often characterized by pronounced impairment in visuospatial skills, attention, and executive functions. However, the strength of the phenotypic expression of DLB varies and may be weaker in patients with extensive concomitant Alzheimer’s disease (AD). To determine whether strength of the DLB clinical phenotype impacts cognitive decline, visuospatial and language tests were retrospectively used to predict two-year rate of global cognitive decline in 22 autopsy-confirmed DLB patients (21 with concomitant AD) and 44 autopsy-confirmed “pure” AD patients. Generalized Estimating Equations (GEE) revealed a significant interaction such that poor baseline performances on tests of visuospatial skills were strongly associated with a rapid rate of cognitive decline in DLB but not AD (p < .001). No effect of confrontation naming was found. DLB patients with poor visuospatial skills had fewer neurofibrillary tangles and were more likely to experience visual hallucinations than those with better visuospatial skills. These results suggest that the severity of visuospatial deficits in DLB may identify those facing a particularly malignant disease course and may designate individuals whose clinical syndrome is impacted more by Lewy body formation than AD pathology.
Dementia with Lewy bodies; cognitive decline; visuospatial skills; Alzheimer’s disease
The vitamin E and donepezil trial for the treatment of amnestic mild cognitive impairment (MCI) was conducted at 69 centers in North America; 24 centers participated in an MRI sub study. The objective of this study was to evaluate the effect of treatment on MRI atrophy rates; and validate rate measures from serial MRI as indicators of disease progression in multi center therapeutic trials for MCI. Annual percent change (APC) from baseline to follow-up was measured for hippocampus, entorhinal cortex, whole brain, and ventricle in the 131 subjects who remained in the treatment study and completed technically satisfactory baseline and follow-up scans. Although a non-significant trend toward slowing of hippocampal atrophy rates was seen in APOE ∈4 carriers treated with donepezil; no treatment effect was confirmed for any MRI measure in either treatment group. For each of the four brain atrophy rate measures, APCs were greater in subjects who converted to AD than non-converters, and were greater in APOE ∈4 carriers than non-carriers. MRI APCs and changes in cognitive test performance were uniformly correlated in the expected direction (all p < 0.000). Results of this study support the feasibility of using MRI as an outcome measure of disease progression in multi center therapeutic trials for MCI.
dementia; Alzheimer's disease; mild cognitive impairment; clinical trials; therapeutic trials; MRI; magnetic resonance imaging; serial MRI; longitudinal imaging; brain atrophy; brain atrophy rates
Blood levels of homocysteine may be elevated in Alzheimer’s disease (AD), and hyperhomocysteinemia may contribute to disease pathophysiology by vascular and direct neurotoxic mechanisms. Even in the absence of vitamin deficiency, homocysteine levels can be reduced by administration of high-dose supplements of folic acid and vitamins B6 and B12. Prior studies of B vitamins to reduce homocysteine in AD have not had sufficient size or duration to assess impact on cognitive decline.
To determine the efficacy and safety of B vitamin supplementation in the treatment of AD.
We conducted a multicenter, randomized, double-blind controlled clinical trial of high-dose folate/B6/B12 supplementation in individuals with AD.
The study was conducted between March, 2003 and February, 2007 at clinical research sites of the Alzheimer’s Disease Cooperative Study located throughout the US.
A total of 409 participants (out of 601 screened) with mild to moderate AD (Mini-Mental Status Scores between 14 and 26, inclusive) and normal folic acid, B12 and homocysteine levels were enrolled in this trial; 340 completed the trial on study medication.
Participants were randomly assigned to two groups of unequal size: 60% were treated with daily high-dose supplements (folate 5mg, vitamin B6 25mg, vitamin B12 1 mg), and 40% were treated with identical placebo; the duration of treatment was 18 months.
Main Outcome Measure
The primary outcome measure was the change in the cognitive subscale of the Alzheimer’s Disease Assessment Scale (ADAScog).
Although the vitamin supplement regimen was effective in reducing homocysteine levels (active −2.42±3.35; placebo -0.86±2.59; p<0.001), it had no beneficial effect on the primary cognitive measure, rate of change in ADAS-Cog over 18 months (placebo: 0.372 point/month vs active: 0.401 point/month, p-value=0.522, CI of rate difference: (−0.06, 0.12), based on the Generalized Estimating Equations (GEE) model), or on any secondary measures. A higher rate of adverse events involving depression was observed in the group treated with vitamin supplements.
This regimen of high dose B vitamin supplements does not slow cognitive decline in individuals with mild to moderate AD.
Evaluate the safety, tolerability and amyloid beta (Aβ) response to a γ-secretase inhibitor (LY450139) in Alzheimer's disease.
Multi-center, randomized, double-blind, dose-escalation, placebo-controlled trial.
Community based clinical research centers.
51 participants with mild to moderate AD were randomized (placebo=15, 100mg=22, 140mg=14), with 43 completing the treatment phase.
Subjects randomized to LY450139 received 60mg daily for 2 weeks followed by 100mg for 6 weeks, then re-randomized to 100mg or 140mg for 6 additional weeks.
Main Outcome Measures
Primary outcome measures consisted of adverse events, plasma and cerebrospinal fluid Aβ levels, vital signs, electrocardiogram data, and laboratory safety tests. Secondary outcome measures included the ADAS-cognitive subscale and the ADCS-Activities of Daily Living scale.
Group differences were seen in “skin and subcutaneous tissue” complaints (p=0.052). These included 3 possible drug rashes and 3 reports of hair color change in the treatment groups. There were 3 adverse-event-related discontinuations, including one report of transient bowel obstruction. Plasma Aβ40 was reduced by 58.2% for the 100mg group and 64.6% for the 140mg group (P<0.001). No significant reduction was seen in CSF Aβ. No group differences were seen in cognitive or functional measures.
LY450139 was generally well tolerated at doses of up to 140mg taken daily for 14 weeks with several findings indicating the need for close clinical monitoring in future studies. Decreases in plasma Aβ concentrations were consistent with inhibition of γ-secretase.
Alzheimer's disease; amyloid; gamma secretase; clinical trial
The association between the epsilon-4 type allele of apolipoprotein E (APOE ε4) and depression was investigated in 323 AD patients. Patients were divided into two groups based on the presence (n=61) or absence (n=262) of depression as assessed by the DSM-based Diagnostic Interview Schedule. Both subgroups were demographically comparable with regard to age, education, gender, and severity of cognitive impairment. Analysis of the frequency of APOE ε4 alleles between the groups revealed a significantly higher prevalence rate of the APOE ε4 genotype in the depressed group (72% of depressed AD patients carried at least one copy of the ε4 allele) compared to the non-depressed AD patients (58%). This effect was primarily accounted for by women. Specifically, an interaction was revealed wherein women who possessed the APOE ε4 allele were almost 4 times more likely to be depressed in comparison to those who did not carry the allele, and APOE ε4 status did not predict depression among men in our sample. These results are consistent with recent suggestions that the APOE ε4 genotype may be over-represented among women with AD and depression and highlight a need for additional research investigating the links between APOE genotype, mood, and gender.
With the increasing life expectancy in developed countries, the incidence of Alzheimer’s disease (AD) and thus its socioeconomic impact are growing. Increasing knowledge over the last years about the pathomechanisms involved in AD allow for the development of specific treatment strategies aimed at slowing down or even preventing neuronal death in AD. However, this requires also that (1) AD can be diagnosed with high accuracy, because non-AD dementias would not benefit from an AD-specific treatment; (2) AD can be diagnosed in very early stages when any intervention would be most effective; and (3) treatment efficacy can be reliably and meaningfully monitored. Although there currently is no ideal biomarker that would fulfill all these requirements, there is increasing evidence that a combination of currently existing neuroimaging and cerebrospinal fluid (CSF) and blood biomarkers can provide important complementary information and thus contribute to a more accurate and earlier diagnosis of AD. The Alzheimer’s Disease Neuroimaging Initiative (ADNI) is exploring which combinations of these biomarkers are the most powerful for diagnosis of AD and monitoring of treatment effects.
Positron-emission tomography; Single photon emission tomography; Magnetic resonance imaging; Biochemical biomarker; Genetic biomarker
Biomarkers are likely to be important in the study of Alzheimer disease (AD) for a variety of reasons. A clinical diagnosis of Alzheimer disease is inaccurate even among experienced investigators in about 10% to 15% of cases, and biomarkers might improve the accuracy of diagnosis. Importantly for the development of putative disease-modifying drugs for Alzheimer disease, biomarkers might also serve as indirect measures of disease severity. When used in this way, sample sizes of clinical trials might be reduced, and a change in biomarker could be considered supporting evidence of disease modification. This review summarizes a meeting of the Alzheimer’s Association’s Research Roundtable, during which existing and emerging biomarkers for AD were evaluated. Imaging biomarkers including volumetric magnetic resonance imaging and positron emission tomography assessing either glucose utilization or ligands binding to amyloid plaque are discussed. Additionally, biochemical biomarkers in blood or cerebrospinal fluid are assessed. Currently appropriate uses of biomarkers in the study of Alzheimer disease, and areas where additional work is needed, are discussed.
Alzheimer disease; amyloid beta; cerebrospinal fluid; clinical trials; cytokines; isoprostanes; positron emission tomography; tau; volumetric magnetic resonance imaging
Previous studies of episodic memory report a greater extent of blood-oxygenation-level-dependent (BOLD) response in non-demented older adults with the apolipoprotein E epsilon-4 (APOE ε4) allele than in those without the allele. We conducted a functional MRI study to investigate whether APOE genotype is related to brain response to verbal paired-associate encoding and consolidation, particularly in the right hemisphere, among non-demented older adults. Structurally segmented volumes and BOLD response were measured in 13 non-ε4 and 12 ε4 subjects. The ε4 group displayed greater activation than the non-ε4 group in multiple right hemisphere regions for previously encoded word pairs relative to fixation. Activation within manually outlined hippocampal regions of interest also displayed genotype-specific dissociations consistent with whole brain analyses. Furthermore, this differential BOLD response occurred in the presence of equivalent behavioral and neuropsychological performances as well as comparable hippocampal and overall structural segmentation volumes between groups. Results implicate a widely distributed and interconnected network of right hemisphere brain regions that may be involved in compensating for APOE ε4-related deficiencies associated with verbal episodic memory encoding and consolidation.
Verbal paired-associate encoding; Hippocampus; Apolipoprotein E; BOLD; Episodic memory; Non-demented older adults
The profiles of neuropsychological deficits associated with Alzheimer's disease (AD) in Young-Old (M age < 70) and Very-Old (M age > 80) patients were compared, along with possible modifying effects of apolipoprotein E (APOE) genotype on these profiles. A comprehensive battery of neuropsychological tests was administered to the two AD patient groups (Young-Old: n = 33; Very-Old: n = 48) and their respective age-matched normal control (NC) groups who remained free of dementia on follow-up examinations over a 1 to 10 year period (Young-Old: n = 43; Very-Old: n = 36). AD and NC groups did not differ in education levels or gender distributions. Young-Old AD and Very-Old AD groups were comparable in education, gender, dementia severity, and disease duration. Results showed that both AD groups achieved comparable raw scores on all the neuropsychological measures. However, when scores were standardized on the basis of performance of their respective NC groups (i.e., age-corrected z scores), Very-Old AD patients significantly outperformed Young-Old AD patients on tests of executive functions, visuospatial skills, and delayed memory. Furthermore, the relationship between age and memory and executive function deficits in AD was modified by APOE genotype. These data suggest that the profile of neuropsychological deficits associated with AD in the Very-Old lacks the disproportionate saliency of episodic memory and executive function deficits typical of the Young-Old.
Aging; Alzheimer's disease; Neuropsychology; Apolipoprotein E; Very-old
A subtle decline in episodic memory often occurs prior to the emergence of the full dementia syndrome in nondemented older adults who develop Alzheimer's disease (AD). The APOE-ε4 genotype may engender a more virulent form of AD that hastens this decline. To examine this possibility, we compared the rate of decline in episodic memory during the preclinical phase of AD in individuals with or without at least one APOE ε4 allele. Nondemented normal control (NC; n = 84) participants, nondemented older adults who subsequently developed dementia within 1 or 2 years (i.e., preclinical AD; n = 20), and patients with mild AD (n = 53) were examined with 2 commonly employed tests of episodic memory, the Logical Memory subtest of the Wechsler Memory Scale–Revised and the California Verbal Learning Test. Results revealed a precipitous decline in verbal memory abilities 1 to 2 years prior to the onset of the dementia syndrome, but there was little effect of APOE genotype on the rate of this memory decline. The presence of an APOE-ε4 allele, however, did have a differential effect on the sensitivity of the 2 types of memory tests for tracking progression and made an independent contribution to the prediction of conversion to AD.
Episodic memory; Neuropsychology; Alzheimer's disease; Apolipoprotein E; Preclinical Alzheimer's disease
Animal studies suggest that brain apolipoprotein E (apoE) levels influence amyloid-β (Aβ) deposition and thus risk for Alzheimer's disease (AD). We have previously demonstrated that deletion of the ATP-binding cassette A1 transporter (ABCA1) in mice causes dramatic reductions in brain and cerebrospinal fluid (CSF) apoE levels and lipidation. To examine whether polymorphisms in ABCA1 affect CSF apoE levels in humans, we measured apoE in CSF taken from 168 subjects who were 43 to 91 years old and were either cognitively normal or who had mild AD. We then genotyped the subjects for ten previously identified ABCA1 single nucleotide polymorphisms (SNPs).
In all subjects, the mean CSF apoE level was 9.09 μg/ml with a standard deviation of 2.70 μg/ml. Levels of apoE in CSF samples taken from the same individual two weeks apart were strongly correlated (r2 = 0.93, p < 0.01). In contrast, CSF apoE levels in different individuals varied widely (coefficient of variation = 46%). CSF apoE levels did not vary according to AD status, APOE genotype, gender or race. Average apoE levels increased with age by ~0.5 μg/ml per 10 years (r2 = 0.05, p = 0.003). We found no significant associations between CSF apoE levels and the ten ABCA1 SNPs we genotyped. Moreover, in a separate sample of 1225 AD cases and 1431 controls, we found no association between the ABCA1 SNP rs2230806 and AD as has been previously reported.
We found that CSF apoE levels vary widely between individuals, but are stable within individuals over a two-week interval. AD status, APOE genotype, gender and race do not affect CSF apoE levels, but average CSF apoE levels increase with age. Given the lack of association between CSF apoE levels and genotypes for the ABCA1 SNPs we examined, either these SNPs do not affect ABCA1 function or if they do, they do not have strong effects in the CNS. Finally, we find no evidence for an association between the ABCA1 SNP rs2230806 and AD in a large sample set.
Immunization of patients with Alzheimer’s disease (AD) with synthetic amyloid-β peptide (Aβ42) (AN1792) was previously studied in a randomized, double-blind, placebo-controlled phase 2a clinical trial, Study AN1792(QS-21)-201. Treatment was discontinued following reports of encephalitis. One year follow-up revealed that AN1792 antibody responders showed improvements in cognitive measures as assessed by the neuropsychological test battery (NTB) and a decrease in brain volume compared with placebo.
A follow-up study, Study AN1792(QS-21)-251, was conducted to assess the long-term functional, psychometric, neuroimaging, and safety outcomes of patients from the phase 2a study 4.6 years after immunization with AN1792. The results were analyzed by comparing patients originally identified as antibody responders in the AN1792 phase 2a study with placebo-treated patients.
One hundred and fifty-nine patients/caregivers (30 placebo; 129 AN1792) participated in this follow-up study. Of the 129 AN1792-treated patients, 25 were classified in the phase 2a study as antibody responders (anti-AN1792 titers ≥1:2,200 at any time after the first injection). Low but detectable, sustained anti-AN1792 titers were found in 17 of 19 samples obtained from patients classified as antibody responders in the phase 2a study. No detectable anti-AN1792 antibodies were found in patients not classified as antibody responders in the phase 2a study. Significantly less decline was observed on the Disability Assessment for Dementia scale among antibody responders than placebo-treated patients (p=0.015) after 4.6 years. Significant differences in favor of responders were also observed on the Dependence Scale (p=0.033). Of the small number of patients who underwent a follow-up MRI, antibody responders showed similar brain volume loss during the follow-up period subsequent to the AN1792 phase 2a study compared with placebo-treated patients.
Approximately 4.6 years after immunization with AN1792, patients defined as responders in the phase 2a study maintained low but detectable, sustained anti-AN1792 antibody titers and demonstrated significantly reduced functional decline compared with placebo-treated patients. Brain volume loss in antibody responders was not significantly different from placebo-treated patients approximately 3.6 years from the end of the original study. No further cases of encephalitis were noted. These data support the hypothesis that Aβ immunotherapy may have long-term functional benefits.
Alzheimer’s disease; Immunotherapy; Aβ; amyloid; NTB.