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INTRODUCTION: Alzheimer's Prevention Initiative Generation Study 1 evaluated amyloid beta (Aβ) active immunotherapy (vaccine) CAD106 and BACE‐1 inhibitor umibecestat in cognitively unimpaired 60‐ to 75‐year‐old participants at genetic risk for Alzheimer's disease (AD). The study was reduced in size and terminated early. Results from the CAD106 cohort are presented. METHODS: Sixty‐five apolipoprotein E ε4 homozygotes with/without amyloid deposition received intramuscular CAD106 450 μg (n = 42) or placebo (n = 23) at baseline; Weeks 1, 7, 13; and quarterly; 51 of them had follow‐up Aβ positron emission tomography (PET) scans at 18 to 24 months. RESULTS: CAD106 induced measurable serum Aβ immunoglobulin G titers in 41/42 participants, slower rates of Aβ plaque accumulation (mean [standard deviation] annualized change from baseline in amyloid PET Centiloid: −0.91[5.65] for CAD106 versus 8.36 [6.68] for placebo; P < 0.001), and three amyloid‐related imaging abnormality cases (one symptomatic). DISCUSSION: Despite early termination, these findings support the potential value of conducting larger prevention trials of Aβ active immunotherapies in individuals at risk for AD. Highlights: This was the first amyloid‐lowering prevention trial in persons at genetic risk of late‐onset Alzheimer's disease (AD).Active immunotherapy targeting amyloid (CAD106) was tested in this prevention trial.CAD106 significantly slowed down amyloid plaque deposition in apolipoprotein E homozygotes.CAD106 was generally safe and well tolerated, with only three amyloid‐related imaging abnormality cases (one symptomatic).Such an approach deserves further evaluation in larger AD prevention trials. [ABSTRACT FROM AUTHOR]

Abstract Mathematical models of viral dynamics in vivo provide incredible insights into the mechanisms for the nonlinear interaction between virus and host cell populations, the dynamics of viral drug resistance, and the way to eliminate virus infection from individual patients by drug treatment. The integration of these mathematical models with high-throughput genetic and genomic data within a statistical framework will raise a hope for effective treatment of infections with HIV virus through developing potent antiviral drugs based on individual patients’ genetic makeup. In this opinion article, we will show a conceptual model for mapping and dictating a comprehensive picture of genetic control mechanisms for viral dynamics through incorporating a group of differential equations that quantify the emergent properties of a system.

Abstract Background Despite our increasing recognition of the mechanisms that specify and propagate epigenetic states of gene expression, the pattern of how epigenetic modifications contribute to the overall genetic variation of a phenotypic trait remains largely elusive. Results We construct a quantitative model to explore the effect of epigenetic modifications that occur at specific rates on the genome. This model, derived from, but beyond, the traditional quantitative genetic theory that is founded on Mendel’s laws, allows questions concerning the prevalence and importance of epigenetic variation to be incorporated and addressed. Conclusions It provides a new avenue for bringing chromatin inheritance into the realm of complex traits, facilitating our understanding of the means by which phenotypic variation is generated.

We propose a new goodness-of-fit statistic for evaluating generalized linear models with binary responses on the basis of the sum of standardized residuals. We derive the asymptotic distribution of the sum of standardized residuals statistic and argue that, despite its relative simplicity, it typically outperforms many of the more sophisticated currently used goodness-of-fit statistics. [ABSTRACT FROM AUTHOR]

Background: The Alzheimer's Prevention Initiative (API) Generation Study 1 (NCT0256551) evaluated CAD106, an active immunotherapy against Aβ, in delaying the clinical onset of Alzheimer's disease in a cohort of cognitively unimpaired APOE4 homozygotes. Effect of CAD106 on brain amyloid burden after 2 years was measured by amyloid PET. Previous studies in mild AD showed that doses up to 450μg CAD106 induced sustained Aβ‐antibody response with no major safety concerns (Vandenberghe, 2017). Method: Cognitively unimpaired APOE4 homozygotes age 60‐75 were enrolled using a 5:3 randomization ratio (CAD106 450μg:placebo). Intramuscular injections were administered at 0, 6, 12 weeks and then quarterly with alum as adjuvant. PET scans were conducted at baseline and 2 years mainly with florbetapir. Standard uptake value ratios (SUVRs) were calculated using cortical composite region in reference to cerebellum and converted to centiloids. Result: Out of 65 randomized participants (42:23 CAD106:placebo) 59 were followed for 18 months or longer. Mean age at baseline was 65 years, 68% were female. Mean baseline RBANS total score was 106. Year 2 PET scans were acquired in 35 CAD106 and 16 placebo participants with centiloid mean baseline of 49.5 (38.7). CAD106 induced measurable Aβ‐specific IgG titers in all treated participants. Mean (SD) annualized centiloid change from baseline was +8.4 (6.7) on placebo without change with CAD106 ((‐0.9 (5.7), p<0.0001). The effect was more pronounced in amyloid positives: +9.4 (7.7) on placebo and ‐1.8 (6.0) with CAD106, vs in amyloid negatives: +6.7 (4.7) on placebo and +2.2 (2.8) with CAD106. In the CAD106 arm, the effect on PET correlated with antibody titers, especially for amyloid positive subgroup. Higher incidences for psychiatric (21% vs 13%) and general disorders / injection site (64% vs 22%) adverse events were reported with CAD106 vs placebo. Three cases of ARIA (2 ARIA‐H and 1 ARIA‐E) occurred on CAD106 (none on placebo). Cognition scores remained stable for 18 months in both groups. Conclusion: CAD106 is the first active immunotherapy shown to slow amyloid deposition in humans. Treatment with CAD106 might have a positive risk/benefit profile for prevention of amyloid deposition in high‐risk populations. [ABSTRACT FROM AUTHOR]

Background: Recruitment in the API Generation program and treatment with umibecestat were terminated in July 2019 after detection of an early signal of mild worsening in some measures of cognitive function with umibecestat. Participants were followed to assess the reversibility of these and other observed effects. We will summarize the key clinical results for umibecestat vs placebo during treatment and follow up. Method: Following randomization to umibecestat or placebo, clinical assessments were scheduled at month 3, month 6 and every 6 month thereafter. After discontinuation of study medication, participants underwent a full evaluation within 3 months of the last dose. Data will be presented for visits on‐ and off‐treatment. For visits off‐treatment, results will be compared for visits occurring before vs after wash‐out of umibecestat (> 31 days after last dose). Analysis of cognitive scales in relation to age, sex, genotype and amyloid status, and a safety summary will also be presented. Result: At termination about 650 participants had reached week 26. The final evaluation was performed on most of the 1561 ongoing participants (45% after wash‐out). Worsening was detected in a group‐level comparison at month 3 and month 6 in both studies for the two doses of umibecestat (effect size 0.2‐0.3 for RBANS Total, Immediate and Delayed Memory indices). Analysis from the visits conducted after wash‐out indicated that key cognitive findings seen before wash‐out were reversible: we saw no more between‐group differences in RBANS and no more imbalance in the proportion of participants having a >14‐point decrease in total RBANS or > 1‐point increase in CDR‐SB after wash‐out. Similar findings were also seen in homozygotes without elevated amyloid. Conclusion: The negative effect of umibecestat vs placebo on RBANS and CDR‐SOB was detected as early as month 3 and was detectable throughout the treatment period, but was no longer present after wash‐out of umibecestat. This effect seems to be independent of the presence of brain amyloid. Confirmation of the contemporary reversibility of worsening in measures of cognition is an important result to inform development of future prevention therapies for Alzheimer's disease (AD). [ABSTRACT FROM AUTHOR]

Background: API Generation Program evaluated the effectiveness of the BACE1 inhibitor umibecestat and the active immunotherapy CAD106 in delaying the onset of AD symptoms in APOE4 carriers. Data from imaging (vMRI and PET scans), and fluid biomarkers (blood and CSF) were collected during the 12‐week Screening phase. In this presentation, we will summarize results across the two studies and investigate the relationships between the various biomarkers and key baseline characteristics. Method: Amyloid levels were assessed via CSF and/or Amyloid PET scan in both studies for the APOE4 carriers. Generation Study 2 enrolled heterozygotes based on the following elevated amyloid inclusion criteria: Roche Elecsys® CSF p‐Tau/Abeta42 ratio > 0.024 and/or PET scans with any of the 3 amyloid F18 tracers (florbetapir, flutemetamol or florbetaben). If the centralized visual read of PET scan was negative, the SUVr was calculated (cortical composite in reference to whole cerebellum) for the three tracers in order to assess borderline cases. Thresholds for amyloid positivity equivalent to SUVR of 1.1 with florbetapir were used for the final decision on inclusion. Result: Across both studies, over 500 lumbar punctures, 2700 amyloid PET scans and about 150 tau PET scans (conducted using flortaucipir) were performed. In Generation Study 1, over 200 FDG PET scans were also performed. Participants underwent amyloid testing during screening, blood sampling (plasma and serum) and underwent MRI scans for safety and to measure brain volumes. All baseline biomarker data will be presented, including available concentrations from CSF Tau/p‐Tau/Aβ42/Aβ40 along with the eligibility ratio for pTau/ab42. In about 150 participants, concordance between elevated/non elevated amyloid status by CSF and PET (using centiloids) will be shown. Baseline brain volume (whole brain and hippocampus) will be summarized for the different co‐variates (age, sex, cognition, genotype and amyloid status). Correlations among the various fluid biomarkers and imaging will be discussed. Conclusion: These data describe the biomarker signature of the world's largest cohort of cognitively unimpaired APOE4 carriers with and without elevated amyloid. The anonymized study data, biomarker samples as well as images collected will be shared with the scientific community after study completion and reporting. ELECSYS is a registered trademark of Roche. [ABSTRACT FROM AUTHOR]

Background: In addition to early mild non‐progressive cognitive worsening, BACE inhibitors have been associated with early non‐progressive reductions in hippocampal and whole brain volume in trial participants with elevated amyloid (A+, Egan et al, 2019). We have begun to evaluate the effects of umibecestat treatment and discontinuation on cognitively unimpaired amyloid‐positive (A+) and A‐ APOE4 homozygotes and A+ heterozygotes, testing the hypotheses that BACE inhibitor‐related hippocampal and whole brain shrinkage is apparent soon after treatment initiation, non‐progressive, limited to A+ participants, and reversible following discontinuation. Method: The API Generation Program had begun to evaluate umibecestat in 1,623 cognitively unimpaired 60‐75 year‐old participants including 921 A+ APOE4 heterozygotes and 702 homozygotes (A+ or A‐).Following randomization, volumetric brain MRIs were scheduled at month 6, month 12 and then annually. After discontinuation of study medication, participants continued to be assessed under double‐blind conditions, and MRIs were acquired within 3 months after the last dose. We investigated 6‐month hippocampal and whole brain volume changes and their relationship to RBANS immediate, delayed and total memory score changes; and we plan to investigate the persistence or reversibility of these changes within 3 months of discontinuation after study completion in Q2 2020. Result: Umibecestat was associated with significant 6‐month hippocampal and whole brain shrinkage in the aggregate APOE4 homozygote and A+ heterozygote group, but not in the A‐ homozygotes. While an early non‐progressive worsening in RBANS immediate, delayed, and total memory scores (Graf et al, AAIC 2020 submitted) was seen in the overall population as well as in A‐ HMs, we failed to demonstrate any significant association between brain shrinkage and cognitive worsening in the overall group (R2 coefficient <0.1) in the active treatment group for any of the visits (on‐ and off‐ treatment). Conclusion: BACE inhibitor‐related brain shrinkage appears to be early, non‐progressive, related to pre‐existing amyloid plaque burden, and unrelated to its cognitive worsening. Pending findings will help to clarify the extent to which it is also reversible. Together, our cognitive and MRI findings could help to assess potential benefits versus risks of BACE inhibitors in future prevention trials. [ABSTRACT FROM AUTHOR]

Background: The Alzheimer Prevention Initiative (API) Generation Program evaluated the effectiveness of the BACE1 inhibitor, umibecestat, and the active immunotherapy, CAD106, in delaying the onset of AD symptoms in APOE4 carriers. The Generation Program included two studies implemented in 23 countries at 207 sites. Recruitment in the program and treatment with umibecestat was terminated in July 2019 after detecting an early signal of mild worsening in some measures of cognitive function with umibecestat. We will summarize the baseline characteristics of participants in the Generation Program. Method: Treatment duration was planned for 5‐8 years in two double‐blind, placebo‐controlled, parallel design studies (Lopez Lopez et al., 2019) in cognitively unimpaired participants aged 60‐75 years, at risk for onset of clinical symptoms due to AD. Generation Study 1 (NCT0256551) recruited APOE4 homozygotes (HMs) while Generation Study 2 (NCT03131453) enrolled both HMs as well as APOE4 heterozygotes (HTs) if they also had elevated brain amyloid (assessed by either PET and/or CSF). Both studies included a 12‐week screening phase starting with genotyping. Amyloid testing was the last screening assessment performed before randomization. Result: Among the 9623 participants recruited, more than 2700 completed the 12‐week Screening phase with amyloid testing. Approximately 27% were HMs. About 60% of HMs and 35% of HTs had elevated brain amyloid. A total of 1623 participants were randomized: 478 to Generation Study 1 (all HMs) and 1145 to Generation Study 2 (including 20% HMs and 80% HTs with elevated amyloid). Education, sex, family history of AD, clinical scales (including MMSE, RBANS total score and indices, CDR sum of boxes, and ECog), brain volumes and amyloid status will be shown. Scores from cognitive scales will be presented by sex, genotype (E4/E4, E3/E4, E2/E4), age group and amyloid status. Conclusion: The Generation program collected a broad set of parameters for the world's largest cohort of cognitively unimpaired APOE4 carriers. Baseline characteristics of participants enrolled in the Generation Program were consistent with the target population at risk for AD. Findings in relation to genotype, age, sex and amyloid status will be discussed. [ABSTRACT FROM AUTHOR]

Introduction: The Alzheimer's Prevention Initiative (API) Generation Studies evaluated the BACE inhibitor umibecestat for Alzheimer's disease (AD) prevention. The studies were terminated early, and the reversibility of umibecestat's side effects was assessed., Methods: Cognitively unimpaired 60- to 75-year-old apolipoprotein E (APOE) ε4 homozygotes and heterozygotes (the latter with elevated brain amyloid deposition) (n = 1556) received umibecestat (50 or 15 mg daily) or placebo for 7 months on average and were followed for a median (interquartile range) of 4 (3 to 6) months after washout., Results: Compared to placebo, umibecestat-treated participants had small, non-progressive, but statistically significant decline in performance on certain cognitive batteries including Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and API Preclinical Composite Cognitive test, but not Clinical Dementia Rating-Sum of Boxes. RBANS differences were no longer significant at the end of follow-up., Discussion: In people at genetic risk for AD, high-dose beta-site amyloid precursor protein cleaving enzyme (BACE) inhibition was associated with early mild cognitive worsening, which reversed shortly after washout, suggesting a symptomatic side effect not associated with neurodegeneration. Fully anonymized data, images, and samples are available upon request for further research on BACE inhibition., Highlights: This is the first trial with blinded assessment of reversibility of BACE inhibitor side effects. Umibecestat was tested in cognitively unimpaired persons at genetic risk for AD. Umibecestat led to early mild cognitive decline that reversed shortly after washout. This suggests a potentially manageable effect not associated with neurodegeneration. Further research may determine the future of BACE inhibition in AD prevention., (© 2024 Novartis Pharma AG. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Introduction: Alzheimer's Prevention Initiative Generation Study 1 evaluated amyloid beta (Aβ) active immunotherapy (vaccine) CAD106 and BACE-1 inhibitor umibecestat in cognitively unimpaired 60- to 75-year-old participants at genetic risk for Alzheimer's disease (AD). The study was reduced in size and terminated early. Results from the CAD106 cohort are presented., Methods: Sixty-five apolipoprotein E ε4 homozygotes with/without amyloid deposition received intramuscular CAD106 450 μg (n = 42) or placebo (n = 23) at baseline; Weeks 1, 7, 13; and quarterly; 51 of them had follow-up Aβ positron emission tomography (PET) scans at 18 to 24 months., Results: CAD106 induced measurable serum Aβ immunoglobulin G titers in 41/42 participants, slower rates of Aβ plaque accumulation (mean [standard deviation] annualized change from baseline in amyloid PET Centiloid: -0.91[5.65] for CAD106 versus 8.36 [6.68] for placebo; P < 0.001), and three amyloid-related imaging abnormality cases (one symptomatic)., Discussion: Despite early termination, these findings support the potential value of conducting larger prevention trials of Aβ active immunotherapies in individuals at risk for AD., Highlights: This was the first amyloid-lowering prevention trial in persons at genetic risk of late-onset Alzheimer's disease (AD). Active immunotherapy targeting amyloid (CAD106) was tested in this prevention trial. CAD106 significantly slowed down amyloid plaque deposition in apolipoprotein E homozygotes. CAD106 was generally safe and well tolerated, with only three amyloid-related imaging abnormality cases (one symptomatic). Such an approach deserves further evaluation in larger AD prevention trials., (© 2023 Novartis. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)