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A preliminary analysis of a trial involving participants with brain amyloid deposition who are at risk for dementia due to Alzheimer’s disease showed no benefit of a β-secretase enzyme inhibitor over placebo and a potential signal of worse cognitive test scores over 3 and 6 months.

In two phase 3 placebo-controlled, randomized trials in 1012 and 1040 patients with mild-to-moderate Alzheimer's disease, solanezumab, a humanized monoclonal antibody that preferentially binds soluble forms of amyloid, did not improve cognition or functional status. Alzheimer's disease is associated with the accumulation of aggregated amyloid-beta (Aβ) peptide in the cerebral cortex and hippocampus. One approach to reducing brain amyloid involves increasing the clearance of Aβ by means of prolonged treatment with monoclonal antibodies directed against this peptide. In preclinical studies, a murine antibody that targeted the central domain of Aβ and was selective for soluble forms slowed Aβ deposition in a transgenic mouse model 1 ; in another transgenic murine model, Aβ–antibody complexes were present in the cerebrospinal fluid (CSF) and plasma, and behavioral deficits were reversed without a decrease in amyloid plaques, as assessed by . . .

Intranasal insulin (INI) has shown promise as a treatment for Alzheimer’s disease (AD) in pilot clinical trials. In a recent phase 2 trial, participants with mild cognitive impairment (MCI) or AD who were treated with INI with one of two delivery devices showed improved cerebral spinal fluid (CSF) biomarker profiles and slower symptom progression compared with placebo. In the cohort which showed benefit, we measured changes in CSF markers of inflammation, immune function and vascular integrity and assessed their relationship with changes in cognition, brain volume, and CSF amyloid and tau concentrations. The insulin-treated group had increased CSF interferon-γ (p = 0.032) and eotaxin (p = 0.049), and reduced interleukin-6 (p = 0.048) over the 12 month trial compared to placebo. Trends were observed for increased CSF macrophage-derived chemokine for the placebo group (p = 0.083), and increased interleukin-2 in the insulin-treated group (p = 0.093). Insulin-treated and placebo groups showed strikingly different patterns of associations between changes in CSF immune/inflammatory/vascular markers and changes in cognition, brain volume, and amyloid and tau concentrations. In summary, INI treatment altered the typical progression of markers of inflammation and immune function seen in AD, suggesting that INI may promote a compensatory immune response associated with therapeutic benefit.

In this placebo-controlled trial, the γ-secretase inhibitor semagacestat did not improve cognitive status in patients with Alzheimer's disease and was associated with more adverse events than placebo, including skin cancers and infections. Alzheimer's disease begins decades before the appearance of clinical symptoms, with the deposition of aggregated amyloid-beta (Aβ) peptide plaques in the cortex and hippocampus. This protein is cleaved from the amyloid precursor protein (APP) by the sequential action of β- and γ-secretases, producing fragments that include Aβ1-40 and Aβ1-42. Since the accumulation of aggregated Aβ is associated with disease progression, both β-secretase and γ-secretase represent potential therapeutic targets. Multiple small molecules can inhibit γ-secretase in vitro, 1 – 4 but Notch and other transmembrane proteins are also substrates for γ-secretase, 1 – 4 and studies have raised concern that the inhibition of γ-secretase could . . .

Trials of monoclonal antibodies that target various forms of amyloid at different stages of Alzheimer's disease have had mixed results. We tested solanezumab, which targets monomeric amyloid, in a phase 3 trial involving persons with preclinical Alzheimer's disease. Persons 65 to 85 years of age with a global Clinical Dementia Rating score of 0 (range, 0 to 3, with 0 indicating no cognitive impairment and 3 severe dementia), a score on the Mini-Mental State Examination of 25 or more (range, 0 to 30, with lower scores indicating poorer cognition), and elevated brain amyloid levels on F-florbetapir positron-emission tomography (PET) were enrolled. Participants were randomly assigned in a 1:1 ratio to receive solanezumab at a dose of up to 1600 mg intravenously every 4 weeks or placebo. The primary end point was the change in the Preclinical Alzheimer Cognitive Composite (PACC) score (calculated as the sum of four z scores, with higher scores indicating better cognitive performance) over a period of 240 weeks. A total of 1169 persons underwent randomization: 578 were assigned to the solanezumab group and 591 to the placebo group. The mean age of the participants was 72 years, approximately 60% were women, and 75% had a family history of dementia. At 240 weeks, the mean change in PACC score was -1.43 in the solanezumab group and -1.13 in the placebo group (difference, -0.30; 95% confidence interval, -0.82 to 0.22; P = 0.26). Amyloid levels on brain PET increased by a mean of 11.6 centiloids in the solanezumab group and 19.3 centiloids in the placebo group. Amyloid-related imaging abnormalities (ARIA) with edema occurred in less than 1% of the participants in each group. ARIA with microhemorrhage or hemosiderosis occurred in 29.2% of the participants in the solanezumab group and 32.8% of those in the placebo group. Solanezumab, which targets monomeric amyloid in persons with elevated brain amyloid levels, did not slow cognitive decline as compared with placebo over a period of 240 weeks in persons with preclinical Alzheimer's disease. (Funded by the National Institute on Aging and others; A4 ClinicalTrials.gov number, NCT02008357.).

INTRODUCTION Incorporating blood‐based Alzheimer's disease biomarkers such as tau and amyloid beta (Aβ) into screening algorithms may improve screening efficiency. METHODS Plasma Aβ, phosphorylated tau (p‐tau)181, and p‐tau217 concentration levels from AHEAD 3–45 study participants were measured using mass spectrometry. Tau concentration ratios for each proteoform were calculated to normalize for inter‐individual differences. Receiver operating characteristic (ROC) curve analysis was performed for each biomarker against amyloid positivity, defined by > 20 Centiloids. Mixture of experts analysis assessed the value of including tau concentration ratios into the existing predictive algorithm for amyloid positron emission tomography status. RESULTS The area under the receiver operating curve (AUC) was 0.87 for Aβ42/Aβ40, 0.74 for phosphorylated variant p‐tau181 ratio (p‐tau181/np‐tau181), and 0.92 for phosphorylated variant p‐tau217 ratio (p‐tau217/np‐tau217). The Plasma Predicted Centiloid (PPC), a predictive model including p‐tau217/np‐tau217, Aβ42/Aβ40, age, and apolipoprotein E improved AUC to 0.95. DISCUSSION Including plasma p‐tau217/np‐tau217 along with Aβ42/Aβ40 in predictive algorithms may streamline screening preclinical individuals into anti‐amyloid clinical trials. ClinicalTrials.gov Identifier: NCT04468659 Highlights The addition of plasma phosphorylated variant p‐tau217 ratio (p‐tau217/np‐tau217) significantly improved plasma biomarker algorithms for identifying preclinical amyloid positron emission tomography positivity. Prediction performance at higher NAV Centiloid levels was improved with p‐tau217/np‐tau217. All models generated for this study are incorporated into the Plasma Predicted Centiloid (PPC) app for public use.

Underrepresentation of many racial/ethnic groups in Alzheimer disease (AD) clinical trials limits generalizability of results and hinders opportunities to examine potential effect modification of candidate treatments. To examine racial and ethnic differences in recruitment methods and trial eligibility in a multisite preclinical AD trial. This cross-sectional study analyzed screening data from the Anti-Amyloid in Asymptomatic AD study, collected from April 2014 to December 2017. Participants were categorized into 5 mutually exclusive ethnic/racial groups (ie, Hispanic, Black, White, Asian, and other) using participant self-report. Data were analyzed from May through December 2020 and included 5945 cognitively unimpaired older adults between the ages of 65 and 85 years screened at North American study sites. Primary outcomes included recruitment sources, study eligibility, and ineligibility reasons. To assess the probability of trial eligibility, regression analyses were performed for the likelihood of being eligible after the first screening visit involving clinical and cognitive assessments. Screening data were included for 5945 participants at North American sites (mean [SD] age, 71.7 [4.9] years; 3524 women [59.3%]; 5107 White [85.9%], 323 Black [5.4%], 261 Hispanic [4.4%], 112 Asian [1.9%], and 142 [2.4%] who reported race or ethnicity as other). Recruitment sources differed by race and ethnicity. While White participants were recruited through a variety of sources, site local recruitment efforts resulted in the majority of Black (218 [69.2%]), Hispanic (154 [59.7%]), and Asian (61 [55.5%]) participants. Participants from underrepresented groups had lower mean years of education (eg, mean [SD] years: Hispanic participants, 15.5 [3.2] years vs White participants, 16.7 [2.8] years) and more frequently were women (226 [70.0%] Black participants vs 1364 [58.5%] White participants), were unmarried (184 [56.9%] Black participants vs 1364 [26.7%] White participants), and had nonspousal study partners (237 [73.4%] Black participants vs 2147 [42.0%] White participants). They were more frequently excluded for failure to meet cognitive inclusion criteria (eg, screen failures by specific inclusion criteria: 147 [45.5%] Black participants vs 1338 [26.2%] White participants). Compared with White participants, Black (odds ratio [OR], 0.43; 95% CI, 0.34-0.54; P < .001), Hispanic (OR, 0.53; 95% CI, 0.41-0.69; P < .001), and Asian participants (OR, 0.56; 95% CI, 0.38-0.82; P = .003) were less likely to be eligible after screening visit 1. Racial/ethnic groups differed in sources of recruitment, reasons for screen failure, and overall probability of eligibility in a preclinical AD trial. These results highlight the need for improved recruitment strategies and careful consideration of eligibility criteria when planning preclinical AD clinical trials.

To increase the effective use of thrombolytics for acute stroke, the expertise of vascular neurologists must be disseminated more widely. We prospectively assessed whether telemedicine (real-time, two-way audio and video, and digital imaging and communications in medicine [DICOM] interpretation) or telephone was superior for decision making in acute telemedicine consultations. From January, 2004, to August, 2007, patients older than 18 years who presented with acute stroke symptoms at one of four remote spoke sites were randomly assigned, through a web-based, permuted blocks system, to telemedicine or telephone consultation to assess their suitability for treatment with thrombolytics, on the basis of standard criteria. The primary outcome measure was whether the decision to give thrombolytic treatment was correct, as determined by central adjudication. Secondary outcomes were the rate of thrombolytic use, 90-day functional outcomes (Barthel index [BI] and modified Rankin scale [mRS]), the incidence of intracerebral haemorrhages, and technical observations. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00283868. 234 patients were assessed prospectively. 111 patients were randomised to telemedicine, and 111 patients were randomised to telephone consultation; 207 completed the study. Mean National Institutes of Health stroke scale score at presentation was 9·5 (SD 8·1) points (11·4 [8·7] points in the telemedicine group versus 7·7 [7·0] points in the telephone group; p=0·002). One telemedicine consultation was aborted for technical reasons, although it was included in the analyses. Correct treatment decisions were made more often in the telemedicine group than in the telephone group (108 [98%] vs 91 [82%], odds ratio [OR] 10·9, 95% CI 2·7–44·6; p=0·0009). Intravenous thrombolytics were used at an overall rate of 25% (31 [28%] telemedicine vs 25 [23%] telephone, 1·3, 0·7–2·5; p=0·43). 90-day functional outcomes were not different for BI (95–100) (0·6, 0·4–1·1; p=0·13) or for mRS score (0·6, 0·3–1·1; p=0·09). There was no difference in mortality (1·6, 0·8–3·4; p=0·27) or rates of intracerebral haemorrhage after treatment with thrombolytics (2 [7%] telemedicine vs 2 [8%] telephone, 0·8, 0·1–6·3; p=1·0). However, there were more incomplete data in the telephone group than in the telemedicine group (12% vs 3%, 0·2, 0·1–0·3; p=0·0001). The authors of this trial report that stroke telemedicine consultations result in more accurate decision making compared with telephone consultations and can serve as a model for the effectiveness of telemedicine in other medical specialties. The more appropriate decisions, high rates of thrombolysis use, improved data collection, low rate of intracerebral haemorrhage, low technical complications, and favourable time requirements all support the efficacy of telemedicine for making treatment decisions, and might enable more practitioners to use this medium in daily stroke care. National Institute of Neurological Disorders and Stroke; California Institute of Telecommunications Technology; Department of Veterens' Affairs Research Division.

We identified axonal defects in mouse models of Alzheimer's disease that preceded known disease-related pathology by more than a year; we observed similar axonal defects in the early stages of Alzheimer's disease in humans. Axonal defects consisted of swellings that accumulated abnormal amounts of microtubule-associated and molecular motor proteins, organelles, and vesicles. Impairing axonal transport by reducing the dosage of a kinesin molecular motor protein enhanced the frequency of axonal defects and increased amyloid-{szligbeta} peptide levels and amyloid deposition. Reductions in microtubule-dependent transport may stimulate proteolytic processing of {szligbeta}-amyloid precursor protein, resulting in the development of senile plaques and Alzheimer's disease.

Background The enrollment into clinical trials of persons at risk for autosomal dominant Alzheimer’s disease (ADAD) in whom the onset of disease can be accurately predicted facilitates the interpretation of outcomes (e.g., biomarkers, treatment efficacy). Attitudes toward involvement in such studies are biased by intrinsic cultural and social characteristics. Our objective was to study how demographic factors such as country of residence, age, sex, schooling, parenthood, and urbanization affect attitudes towards participation in hypothetical clinical trials in Mexican families at risk for ADAD living either in Mexico or in the United States. Methods Participants were 74 members of different families known to harbor an ADAD mutation living in Mexico ( n = 50) or in the United States ( n = 24). Participants were asked, in a written questionnaire, their interest in participating in four hypothetical clinical trial scenarios of increasing perceived invasiveness. The questionnaire then asked about their willingness should there be a 50% chance of being assigned to a placebo group. The influences of demographic variables on decisions were performed using Wilcoxon rank-sum for continuous variables and Fisher’s exact test for categorical variables. Results Participants who live in Mexico, who have or plan to have children, who do not attend or do not plan to attend school, and who live in rural areas gave more positive responses regarding their willingness to participate compared to those living in the U.S. The 50% chance of being in a placebo group increased the willingness to participate for family members living in Mexico. The main reason for participation was to help future generations, while the main reasons for refusal were not wanting to undergo genetic testing and consideration of adverse effects. Conclusions We found a higher level of willingness to participate in clinical trials among persons living in rural Mexico and our data suggest that altruism towards future generations is a major motivation, though this was balanced against concerns regarding side effects. Our results emphasize the importance of sharing information and assessing its understanding in potential participants with diverse backgrounds in the nature of ADAD and regarding the design of clinical trials prior to their enrollment in such studies.