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Alzheimer's Association International Conference (AAIC) · 2024:Poster Tue-17 · Hendrix, Dickson et al.
Companies recently identified clinical study sites engaging in fraudulent practices, reducing success in Alzheimer's disease (AD) clinical trials. Successful trials are reliable…
When the sample size a conventional design demands is larger than the trial you can run, a Global Statistical Test lets the clinical-endpoint hypotheses be tested anyway. The paper sets out when GST applies, how it is pre-specified, and how it has been received in review.
13 publications
Sorted newest first
2015 · Alzheimer's & Dementia
Background: In patients with Alzheimer's disease (AD) either with or without stable cholinesterase inhibitor (ChEI) treatment, clinical trials have shown significant and beneficial Baseline-to-Endpoint effects following memantine (MEM) treatment in comparison with placebo. Time to meaningful levels of change on outcome measures can also provide clinically relevant information for physicians. This new post hoc analysis used a time-to-event Kaplan-Meier methodology to evaluate clinically meaningful changes in four 6-7 month studies of memantine alone or in combination with a ChEI. Methods: The populations of 4 trials were pooled (N=1,628): 3 randomized, double-blind, placebo-controlled trials of MEM IR (10 mg BID; 2 monotherapy; 1 of patients on stable donepezil) and 1 trial of MEM ER (28 mg QD; patients on stable ChEI regimen) in moderate to severe AD. Efficacy outcomes included cognition (SIB), function (ADCS-ADL19), behavior (NPI), and global status (CIBIC-Plus), and clinically meaningful events were defined as the median decline at Endpoint for placebo-only treated patients; the K-M method was used to compare median time to reach this point in the treatment groups and an unadjusted log-rank test was performed on the intent-to-treat population. Results: Meaningful events were defined as declines of ≥4 points on SIB, ≥3 points on ADCS-ADL19, NPI total score increase ≥0, and final score ≥5 for CIBIC-Plus. The median times-to-events (days) were: SIB (PBO-only: 85; PBO+ChEI: 176 [P<0.0001 vs PBO-only]; MEM-only: 188 [P=0.0001 vs PBO-only]; MEM+ChEI: >196 [P<0.0001 vs PBO-only]; all-PBO groups: 168; all-MEM groups: 193 [P=0.0037 vs all-PBO]), ADCS-ADL19 (PBO-only: 125; PBO+ChEI: 127 [P=0.9854 vs PBO-only]; MEM-only: 172 [P=0.0445 vs PBO-only]; MEM+ChEI: 168 [P=0.2390 vs PBO-only]; all-PBO: 127; all-MEM: 168 [P=0.0127 vs all-PBO]), NPI (PBO-only: 85; PBO+ChEI: 84 [P<0.0001 vs PBO-only]; MEM-only: 101 [P=0.3518 vs PBO-only]; MEM+ChEI: 87 [P=0.0333 vs PBO-only]; all-PBO: 85; all-MEM: 88 [P=0.0027 vs all-PBO]), and CIBIC-Plus (PBO-only: 126; PBO+ChEI: 126 [P=0.4567 vs PBO-only]; MEM-only: 168 [P=0.1429 vs PBO-only]; MEM+ChEI: 168 [P=0.4011 vs PBO-only]; all-PBO: 126; all-MEM: 168 [P=0.0205 vs all-PBO]). Conclusions: Time-to-event analyses support the conclusion that memantine alone or in combination with a ChEI is efficacious in delaying cognitive, functional, and behavioral declines in patients with moderate to severe AD.
2015 · Alzheimer's & Dementia: The Journal of the Alzheimer's Association
Background: The exponential growth in patient needs, the tremendous personal and societal burden, the high cost of basic and clinical research, and the enormous investments of pharmaceutical companies to develop new therapies for Alzheimer's disease (AD) remain a big challenge. Despite the considerable evidence that links a reduction in hippocampal volume (HV) in the brains of affected subjects to the pathophysiology of the disease, the role and integration of HV as a biomarker in clinical trials will only be realized on a large scale when this marker is endorsed by regulatory agencies worldwide. In 2011, the European Medicines Agency (EMA) qualified HV measured by MRI as a biomarker. The Coalition Against Major Diseases (CAMD), a consortium within the non-profit organization the Critical Path Institute, aims to qualify with FDA the use of low baseline HV biomarker for enrichment in clinical trials of patients with early AD. The team is at the Consultation and Advice Stage of biomarker qualification. We will present lessons learned. Methods: Through collaborative partnerships between industry, academia, regulatory agencies, and patient advocacy groups, CAMD focuses on the development and regulatory qualification of clinical trials tools, such as HV imaging biomarkers, to increase the efficiency and diminish the risks and costs of drug development. Results: The HV measures proposed for qualification will be applicable independent of the specific drug's mechanism of action or target, the MRI scanner that collected the imaging data, and the algorithm used to measure the HV. Our team has evaluated multiple algorithms in independent clinical cohorts that have longitudinal clinical follow-up, including ADNI. We will discuss our approach to repeatability and reproducibility issues. There is an urgent need to obtain biomarker data from relevant clinical trials to achieve regulatory success. Conclusions: The development of a robust evidentiary package to support the qualification of the HV imaging biomarker for use in clinical trials of patients with AD requires significant resources and commitment from a wide range of stakeholders. Successful qualification of this biomarker is expected to accelerate the advent of new therapies for patients at early stages of the disease.
2015 · The Journal of Prevention of Alzheimer's Disease
Background: Optimized scales and composite outcomes have been proposed as a way to more accurately measure Alzheimer's disease related decline. AFFITOPE® AD02, is an amyloid-beta (Aβ)-targeting vaccine to elicit anti-Aβ antibodies. IMM-AD04, commonly known as Alum, originally designated as a control agent, appeared to have disease-modifying activity in a multicenter, parallel group phase II study in early AD patients. Objectives: To develop adapted outcomes for cognition, function and a composite scale with improved sensitivity to decline and treatment effects in early AD (mild plus prodromal AD) based on historical data and to assess these adapted outcomes in this phase II study. Design: Data from public datasets was analyzed using a partial least squares model in order to identify an optimally weighted cognitive outcome, Adapted ADAS-cog, and an optimally weighted ADL outcome, Adapted ADCS-ADL which were prospectively defined as co-primary endpoints for the study and were also combined into a composite scale. Data from 162 patients in the placebo groups of ADCS studies and 156 mild patients in the ADNI I study were pooled for this analysis. The Adapted ADAS-cog scale considered 13 ADAS-cog items as well as several Neuropsychological test items and CogState items, the Adapted ADCS-ADL considered all ADCS-ADL items. After the pre-specified analyses were complete, additional adapted and composite scales were investigated in a post-hoc manner. Evaluation of the adapted and composite scales was performed on Phase II trial data for AFFITOPE® AD02 (AFF006, Clinical Trial Identifier: NCT01117818) and historic data in early AD. Least square means, standard deviations, and least squares mean to standard deviation ratios were compared among adapted and composite scales and traditional scales for the 5 treatment groups in the phase II study and overall for the historic data. Treatment effect sizes and p-values were also compared for the phase II study. Results: Cognitive items that were selected for the adapted cognitive scale (aADAS-cog) and had the highest weights were Word Recall, Word Recognition, and Orientation. Delayed Word Recall and Digit Cancellation were among the items excluded due to lack of improved sensitivity to decline. Highly weighted ADL items included in the adapted functional scale (aADCS-ADL) were using the telephone, traveling, preparing a meal/snack, selecting clothing, shopping and using appliances. Excluded items were primarily basic ADLs such as eating, walking, toileting and bathing. Comparisons between traditional scales and primary outcome adapted scales show improved sensitivity to group differences with the adapted scales in the phase II trial. Most of the improvement in the sensitivity of the aADAS-cog and the aADCS-ADL is due to a larger treatment difference observed rather than the improved sensitivity to decline in the comparison groups. Conclusion: To our knowledge, this is the first study to prospectively use optimized scales as primary endpoints and to demonstrate the superior power of optimized scales and composites in early disease. Although it is possible that the treatment difference between randomized groups is due to a factor other than the treatment itself, for instance baseline imbalance, the improved power to detect these differences still argues in favor of the adapted scales. The issue of oversensitivity to detect treatment effects is controlled by selection of the alpha level for significance, and in our case will happen less than 5% of the time. Clinical relevance of the treatment difference should be assessed separately from statistical significance, and in this phase II study, is supported by significant or similar sizes of effect on function, behaviour and quality of life outcomes, which are important to patients and caregivers.
2015 · The Journal of Prevention of Alzheimer's Disease
2015 · BMC microbiology
Background: Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) are Gram-negative facultative intracellular pathogens, which are the causative agents of melioidosis and glanders, respectively. Depending on the route of exposure, aerosol or transcutaneous, infection by Bp or Bm can result in an extensive range of disease - from acute to chronic, relapsing illness to fatal septicemia. Both diseases are associated with difficult diagnosis and high fatality rates. About ninety five percent of patients succumb to untreated septicemic infections and the fatality rate is 50 % even when standard antibiotic treatments are administered. Results: The goal of this study is to profile murine macrophage-mediated phenotypic and molecular responses that are characteristic to a collection of Bp, Bm, Burkholderia thailandensis (Bt) and Burkholderia oklahomensis (Bo) strains obtained from humans, animals, environment and geographically diverse locations. Burkholderia spp. (N = 21) were able to invade and replicate in macrophages, albeit to varying degrees. All Bp (N = 9) and four Bm strains were able to induce actin polymerization on the bacterial surface following infection. Several Bp and Bm strains showed reduced ability to induce multinucleated giant cell (MNGC) formation, while Bo and Bp 776 were unable to induce this phenotype. Measurement of host cytokine responses revealed a statistically significant Bm mediated IL-6 and IL-10 production compared to Bp strains. Hierarchical clustering of transcriptional data from 84 mouse cytokines, chemokines and their corresponding receptors identified 29 host genes as indicators of differential responses between the Burkholderia spp. Further validation confirmed Bm mediated Il-1b, Il-10, Tnfrsf1b and Il-36a mRNA expressions were significantly higher when compared to Bp and Bt. Conclusions: These results characterize the phenotypic and immunological differences in the host innate response to pathogenic and avirulent Burkholderia strains and provide insight into the phenotypic alterations and molecular targets underlying host-Burkholderia interactions.
2015 · The Journal of Prevention of Alzheimer's Disease
2015 · Neurology
OBJECTIVE: This subset analysis assessed the efficacy and tolerability of extended-release memantine (MemER; 28 mg/day) in patients with moderate to severe Alzheimer’s disease (AD) receiving donepezil, the most commonly used cholinesterase inhibitor (ChEI). BACKGROUND: In a 24-week randomized trial (N=677) of patients with moderate to severe AD receiving stable ChEI therapy (donepezil, galantamine, or rivastigmine), MemER-treated group significantly outperformed the placebo-treated group on measures of cognition (SIB), global clinical status (CIBIC-Plus), behavior (NPI), and semantic processing ability (VFT), but not on the measure of daily functioning (ADCS-ADL19). DESIGN/METHODS: Prospectively defined assessments in the donepezil subset (MemER/Don, 232; Placebo/Don, 224) utilized the last observation carried forward (LOCF) approach and an ANCOVA model (SIB, NPI, VFT, ADCS-ADL19: baseline-to-endpoint changes) or Cochran-Mantel-Haenszel test (CIBIC-Plus; endpoint scores). Post hoc sensitivity analyses, based on the observed cases (OC), assessed (a) changes from baseline across all visits (mixed-effects model with repeated measures [MMRM]), and (b) areas under the curve (AUC, Week0-Week24; ANCOVA). Tolerability was assessed by examining treatment-emergent adverse events (TEAEs) in the safety population (MemER/Don, 236; Placebo/Don, 227). RESULTS: The prospectively defined analyses revealed a significant endpoint advantage of MemER/Don over Placebo/Don on SIB (P=0.001), NPI (P=0.009), and VFT (P<0.001), but not on CIBIC Plus (P=0.165) or ADCS-ADL19 (P=0.894). The MMRM analysis demonstrated a significant advantage of MemER/Don over Placebo/Don across all visits for SIB (P<0.001), CIBIC-Plus (P=0.008), NPI (P=0.013), and VFT (P<0.001), but not for ADCS-ADL19 (P=0.606), which was corroborated by the AUC analysis (SIB, P=0.028; CIBIC-Plus, P=0.019; NPI, P=0.012; VFT, P=0.008; ADCS-ADL19, P=0.758). Overall TEAE rates were 61.9[percnt] (MemER/Don) and 59.9[percnt] (Placebo/Don). CONCLUSIONS: These analyses suggest that addition of memantine extended release to donepezil in patients with moderate to severe AD is associated with benefits across several clinical domains, with good tolerability. Study Supported by: Forest Laboratories, LLC, a subsidiary of Actavis, Inc.
2015 · Neurology
OBJECTIVE: We assessed the effects of adding memantine to stable cholinesterase inhibitor (ChEI) therapy on neuropsychiatric symptoms in moderate to severe Alzheimer’s disease (AD). BACKGROUND: Neuropsychiatric symptoms are common in moderate to severe AD and associated with caregiving burden; most patients experience several of them at any point in time. Antipsychotics, often used to manage individual symptoms, carry safety risks. Clinical-trial evidence indicates that memantine/ChEI combinations are superior to monotherapy with either drug. DESIGN/METHODS: Data from patients with moderate to severe AD (N=1,140) were pooled from three 24-week, randomized, placebo-controlled trials of memantine added to stable ChEI therapy. Neuropsychiatric symptoms were assessed using the 12-item Neuropsychiatric Inventory (NPI). Total and single-item score changes from baseline at week 24 in all patients and those symptomatic at baseline (total NPI score 蠅1; n=939) were analyzed via ANCOVA (intent-to-treat population, observed cases; α=0.05). Percentages of patients asymptomatic at baseline and at week 24 (total/item NPI score =0) were compared using Fisher’s exact test (α=0.05). RESULTS: At week 24, memantine/ChEI-treated patients significantly outperformed placebo/ChEI-treated patients on the NPI total score (all patients: P=0.001; symptomatic subset: P=0.003) and on the items of agitation (all: P<0.001; symptomatic: P=0.019), appetite/eating change (symptomatic: P=0.037), delusion (all: P=0.038; symptomatic: P=0.039), disinhibition (all: P=0.057; symptomatic: P=0.0497), irritability/lability (all: P=0.009; symptomatic: P=0.055), and nighttime behavior (all: P=0.0495). The percentages of patients who were asymptomatic at both baseline and week 24 on total NPI were not significantly different between groups (memantine/ChEI: 5.6[percnt]; placebo/ChEI: 3.5[percnt], P=0.119). CONCLUSIONS: These results suggest that adding memantine to stable ChEI therapy in individuals with moderate to severe AD may confer benefits in various neuropsychiatric symptoms. Study Supported by: Forest Laboratories, LLC, a subsidiary of Actavis, Inc.
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