Alzheimer's disease progression by geographical region in a clinical trial setting

Cross-sectional and longitudinal assessments of function in prodromal-to-mild Alzheimer's disease: A comparison of the ADCS-ADL and A-IADL-Q scales

Introduction

Prior observational work in a heterogeneous cohort of participants with mild cognitive impairment suggests the Amsterdam Instrumental Activities of Daily Living Questionnaire (A-IADL-Q) may have greater sensitivity for functional decline than the more established Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scale. However, the relative utility of the A-IADL-Q versus the ADCS-ADL for clinical trials in early Alzheimer's disease (AD) remains uncertain.

Methods

We compared baseline and longitudinal performance of the A-IADL-Q and ADCS-ADL in participants with biomarker-confirmed prodromal (pAD; n = 158) or mild (mAD; n = 283) AD enrolled in the 18-month Tauriel study of semorinemab (NCT03289143).

Results

The A-IADL-Q exhibited numerically stronger discrimination between pAD and mAD participants at baseline per Cohen's d analyses and similar sensitivity to longitudinal decline across cohorts over 18 months relative to the ADCS-ADL.

Discussion

The comparable performance of the ADCS-ADL and A-IADL-Q supports the utility of the A-IADL-Q in early AD clinical trials.

Highlights

The Amsterdam Instrumental Activities of Daily Living Questionnaire (A-IADL-Q) may be more sensitive than the Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale (ADCS-ADL) for distinguishing prodromal and mild Alzheimer's disease (AD).A-IADL-Q and ADCS-ADL are similarly sensitive to decline in early AD over 18 months.Comparable performance of these indices supports A-IADL-Q use in future AD trials.Additional AD clinical trial data could extend findings across more diverse cohorts.

An international, randomized, placebo-controlled, phase 2b clinical trial of intepirdine for dementia with Lewy bodies (HEADWAY-DLB)

INTRODUCTION

A phase 2b clinical trial, HEADWAY-DLB, was performed to assess treatment with intepirdine, a serotonin receptor antagonist, in patients with dementia with Lewy bodies (DLB).

METHODS

HEADWAY-DLB was a multinational, double-blind, randomized, placebo-controlled study. Two hundred sixty-nine DLB patients were randomized to receive placebo, 70 mg/day intepirdine, or 35 mg/day intepirdine over 24 weeks. The primary endpoint was change from baseline to week 24 on the Unified Parkinson's Disease Rating Scale-Part III (UPDRS-III).

RESULTS

Both intepirdine groups did not demonstrate significant benefits over placebo at 24 weeks on the UPDRS-III (35 mg/day: P = .1580, 70 mg/day: P = .6069). All other endpoints were not significant. Intepirdine was well tolerated, with a slightly higher incidence of gastrointestinal adverse events observed in the intepirdine groups versus placebo.

DISCUSSION

Intepirdine treatment did not lead to improvements over placebo in patients with DLB. As one of the largest DLB studies to date, HEADWAY-DLB demonstrates that international trials for DLB are feasible within a reasonable timeframe.

Intepirdine as adjunctive therapy to donepezil for mild-to-moderate Alzheimer's disease: A randomized, placebo-controlled, phase 3 clinical trial (MINDSET)

INTRODUCTION

A previous phase 2b study supported the use of the 5-HT6 receptor antagonist intepirdine as adjunctive therapy to donepezil for Alzheimer's disease (AD) dementia. A phase 3 study, MINDSET, was performed to test this hypothesis.

METHODS

MINDSET was a global, double-blind, randomized, placebo-controlled trial in 1315 mild-to-moderate AD dementia patients on stable donepezil. Patients received 35 mg/day intepirdine or placebo for 24 weeks. The co-primary endpoints were change from baseline to week 24 on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL).

RESULTS

There were no statistically significant differences between intepirdine and placebo groups (adjusted mean [95% confidence interval]) on the co-primary endpoints ADAS-Cog (-0.36 [-0.95, 0.22], P = 0.2249) and ADCS-ADL (-0.09 [-0.90, 0.72], P = 0.8260). Intepirdine demonstrated a favorable safety profile similar to placebo.

DISCUSSION

Intepirdine as adjunctive therapy to donepezil did not produce statistical improvement over placebo on cognition or activities of daily living in mild-to-moderate AD dementia patients.

Recruitment and retention of participant and study partner dyads in two multinational Alzheimer's disease registration trials

BACKGROUND

Early study exit is detrimental to statistical power and increases the risk for bias in Alzheimer's disease clinical trials. Previous analyses in early phase academic trials demonstrated associations between rates of trial incompletion and participants' study partner type, with participants enrolling with non-spouse study partners being at greater risk.

METHODS

We conducted secondary analyses of two multinational phase III trials of semagacestat, an oral gamma secretase inhibitor, for mild-to-moderate AD dementia. Cox's proportional hazards regression model was used to estimate the relationship between study partner type and the risk of early exit from the trial after adjustment for a priori identified potential confounding factors. Additionally, we used a random forest model to identify top predictors of dropout.

RESULTS

Among participants with spousal, adult child, and other study partners, respectively, 35%, 38%, and 36% dropped out or died prior to protocol-defined study completion, respectively. In unadjusted models, the risk of trial incompletion differed by study partner type (unadjusted p value = 0.027 for test of differences by partner type), but in models adjusting for potential confounding factors, the differences were not statistically significant (p value = 0.928). In exploratory modeling, participant age was identified as the primary characteristic to explain the relationship between study partner type and the risk of failing to complete the trial. Participant age was also the strongest predictor of trial incompletion in the random forest model.

CONCLUSIONS

After adjustment for age, no differences in the risk of incompletion were observed when comparing participants with different study partner types in these trials. Differences between our findings and the findings of previous studies may be explained by differences in trial phase, size, geographic regions, or the composition of academic and non-academic sites.

Historical Controls in Randomized Clinical Trials: Opportunities and Challenges

Randomized control trials (RCTs) with placebo are the gold standard for determining efficacy of novel pharmaceutical treatments. Since their inception, over 75 years ago, researchers have amassed a large body of underutilized data on outcomes in the placebo control arms of these trials. Although rare disease indications have used these historical placebo data as synthetic controls to reduce burden on patients and accelerate drug discovery, broad use of historical controls is in its infancy. Large-scale historical placebo data could be leveraged to benefit both drug developers and patients if warehoused and made more available to guide trial design and analysis. Here, we examine challenges in utilizing historical controls related to heterogeneity in trial design, outcome ascertainment, patient characteristics, and unmeasured pharmacogenomic effects. We then discuss the advantages and disadvantages of current approaches and propose a path forward to broader use of historical controls in RCTs.

Testing whether the progression of Alzheimer's disease changes with the year of publication, additional design, and geographical area: a modeling analysis of literature aggregate data

BACKGROUND

Our objectives were to develop a disease progression model for cognitive decline in Alzheimer's disease (AD) and to determine whether disease progression of AD is related to the year of publication, add-on trial design, and geographical regions.

METHODS

Placebo-controlled randomized AD clinical trials were systemically searched in public databases. Longitudinal placebo response (mean change from baseline in the cognitive subscale of the Alzheimer's Disease Assessment Scale [ADAS-cog]) and the corresponding demographic information were extracted to establish a disease progression model. Covariate screening and subgroup analyses were performed to identify potential factors affecting the disease progression rate.

RESULTS

A total of 134 publications (140 trials) were included in this model-based meta-analysis. The typical disease progression rate was 5.82 points per year. The baseline ADAS-cog score was included in the final model using an inverse U-type function. Age was found to be negatively correlated with disease progression rate. After correcting the baseline ADAS-cog score and the age effect, no significant difference in the disease progression rate was found between trials published before and after 2008 and between trials using an add-on design and those that did not use an add-on design. However, a significant difference was found among different trial regions. Trials in East Asian countries showed the slowest decline rate and the largest placebo effect.

CONCLUSIONS

Our model successfully quantified AD disease progression by integrating baseline ADAS-cog score and age as important predictors. These factors and geographic location should be considered when optimizing future trial designs and conducting indirect comparisons of clinical outcomes.

Current Landscape of Late-Phase Clinical Trials for Alzheimer's Disease: Comparing Regional Variation Between Subjects in Japan and North America

INTRODUCTION

Over the last few decades, numerous late-phase multi-regional clinical trials have been conducted to develop a novel treatment for Alzheimer's disease (AD), with no effective results.

OBJECTIVE

To inform the design and interpretation of future clinical trials, the aim of this study was first to examine the current landscape of late-phase clinical trials to determine key study design characteristics, and then assess the regional variation between Japan and North America for the most utilized clinical efficacy endpoint in the most targeted stage of the disease.

METHODS

The study design and the mechanism of action of the interventional drugs tested in the late-phase clinical trials initiated in the last 5 years (2014-2018) were assessed based on the records in ClinicalTrials.gov database. The regional variation of the most utilized clinical efficacy endpoint in the most targeted population was assessed using data from two similarly designed observational studies conducted in Japan (Japanese Alzheimer's Disease Neuroimaging Initiative, J-ADNI) and North America (Alzheimer's Disease Neuroimaging Initiative, ADNI). For the most utilized clinical efficacy endpoint, the change from baseline (CFB) at Month 6, Year 1 and Year 2 was estimated using the growth curve model with a random intercept and slope, including gender as a fixed factor and age, apolipoprotein E ε4 genotype and years of education as covariates.

RESULTS

Of 48 Phase III trials that were initiated during the study period, 25 were disease-modifying treatment trials in which individuals with early AD were the most studied (56%) and Clinical Dementia Rating-Sum of Boxes (CDR-SB) was the most frequently utilized primary clinical efficacy endpoint (64%). The baseline characteristics of the early AD population between J-ADNI and ADNI were generally comparable, except for years of education. When comparing CDR-SB in early AD, J-ADNI had generally better baseline scores and the overall progression was similar (CFB at Year 2, ADNI 2.7 and J-ADNI 2.3, p = 0.190), despite slower progression in functional domains (CFB at Year 2, ADNI 1.4 and J-ADNI 1.0, p = 0.031).

CONCLUSION

Over the years, the target population has shifted toward early stage of the disease, wherein the clinical progression is slower and difficult to measure. Moreover, our results suggest that regional variation could have an impact on functional measurements due to cultural differences in pivotal clinical trials. Therefore, caution should be exercised according to the characteristics of the endpoint used.

The "rights" of precision drug development for Alzheimer's disease

There is a high rate of failure in Alzheimer's disease (AD) drug development with 99% of trials showing no drug-placebo difference. This low rate of success delays new treatments for patients and discourages investment in AD drug development. Studies across drug development programs in multiple disorders have identified important strategies for decreasing the risk and increasing the likelihood of success in drug development programs. These experiences provide guidance for the optimization of AD drug development. The "rights" of AD drug development include the right target, right drug, right biomarker, right participant, and right trial. The right target identifies the appropriate biologic process for an AD therapeutic intervention. The right drug must have well-understood pharmacokinetic and pharmacodynamic features, ability to penetrate the blood-brain barrier, efficacy demonstrated in animals, maximum tolerated dose established in phase I, and acceptable toxicity. The right biomarkers include participant selection biomarkers, target engagement biomarkers, biomarkers supportive of disease modification, and biomarkers for side effect monitoring. The right participant hinges on the identification of the phase of AD (preclinical, prodromal, dementia). Severity of disease and drug mechanism both have a role in defining the right participant. The right trial is a well-conducted trial with appropriate clinical and biomarker outcomes collected over an appropriate period of time, powered to detect a clinically meaningful drug-placebo difference, and anticipating variability introduced by globalization. We lack understanding of some critical aspects of disease biology and drug action that may affect the success of development programs even when the "rights" are adhered to. Attention to disciplined drug development will increase the likelihood of success, decrease the risks associated with AD drug development, enhance the ability to attract investment, and make it more likely that new therapies will become available to those with or vulnerable to the emergence of AD.

The rare and the common: scale and the genetic imaginary in Alzheimer's disease drug development

In this paper I examine how the promissory value of genetics is constituted through processes of scale and scaling, focussing on the relationship between "rare" and "common" forms of disease. I highlight the bodies and spaces involved in the production of post-genomic knowledge and technologies of Alzheimer's disease and the development of new disease-modifying drugs. I focus on the example of the development of a monoclonal antibody therapy for Alzheimer's disease. I argue that the process of therapeutic innovation, from genetic studies and animal models to phase III clinical trials, reflects the persistent importance of a genetic imaginary and a mutually constitutive relationship between the rare and the common in in shaping visions of Alzheimer's disease medicine. Approaching this relationship as a question of scale, I suggest the importance of attending to how and where genomic knowledge is "scaled" or proves resistant to scaling.

Incident cognitive impairment: longitudinal changes in molecular, structural and cognitive biomarkers

Longer periods are needed to examine how biomarker changes occur relative to incident sporadic cognitive impairment. We evaluated molecular (CSF and imaging), structural, and cognitive biomarkers to predict incident cognitive impairment and examined longitudinal biomarker changes before and after symptomatic onset. Data from participants who were cognitively normal, underwent amyloid imaging using Pittsburgh compound B and/or CSF studies, and at least two clinical assessments were used. Stepwise Cox proportional hazards models tested associations of molecular (Pittsburgh compound B; CSF amyloid-β42, tau, ptau181, tau/amyloid-β42, ptau181/amyloid-β42), structural (normalized hippocampal volume, normalized whole brain volume), and cognitive (Animal Naming, Trail Making A, Trail Making B, Selective Reminding Test - Free Recall) biomarkers with time to Clinical Dementia Rating (CDR) > 0. Cognitively normal participants (n = 664), aged 42 to 90 years (mean ± standard deviation = 71.4 ± 9.2) were followed for up to 16.9 years (mean ± standard deviation = 6.2 ± 3.5 years). Of these, 145 (21.8%) participants developed a CDR > 0. At time of incident cognitive impairment, molecular, structural, and cognitive markers were abnormal for CDR > 0 compared to CDR = 0. Linear mixed models indicated rates of change in molecular biomarkers were similar for CDR = 0 and CDR > 0, suggesting that the separation in values between CDR = 0 and CDR > 0 must have occurred prior to the observation period. Rate of decline for structural and cognitive biomarkers was faster for CDR > 0 compared to CDR = 0 (P < 0.0001). Structural and cognitive biomarkers for CDR > 0 diverged from CDR 0 at 9 and 12 years before incident cognitive impairment, respectively. Within those who developed CDR > 0, a natural separation occurred for Pittsburgh compound B values. In particular, CDR > 0 who had at least one APOE ɛ4 allele had higher, and more rapid increase in Pittsburgh compound B, while APOE ɛ2 was observed to have slower increases in Pittsburgh compound B. Of molecular biomarker-positive participants followed for at least 10 years (n = 16-23), ∼70% remained CDR = 0 over the follow-up period. In conclusion, conversion from cognitively normal to CDR > 0 is characterized by not only the magnitude of molecular biomarkers but also rate of change in cognitive and structural biomarkers. Findings support theoretical models of biomarker changes seen during transition to cognitive impairment using longitudinal data and provide a potential time for changes seen during this transition. These findings support the use of molecular biomarkers for trial inclusion and cognitive/structural biomarkers for evaluating trial outcomes. Finally, results support a potential role for APOE ɛ in modulating amyloid accumulation in CDR > 0 with APOE ɛ4 being deleterious and APOE ɛ2 protective.

Clinical Trials for Disease-Modifying Therapies in Alzheimer's Disease: A Primer, Lessons Learned, and a Blueprint for the Future

Alzheimer’s disease (AD) has no currently approved disease-modifying therapies (DMTs), and treatments to prevent, delay the onset, or slow the progression are urgently needed. A delay of 5 years if available by 2025 would decrease the total number of patients with AD by 50% in 2050. To meet the definition of DMT, an agent must produce an enduring change in the course of AD; clinical trials of DMTs have the goal of demonstrating this effect. AD drug discovery entails target identification followed by high throughput screening and lead optimization of drug-like compounds. Once an optimized agent is available and has been assessed for efficacy and toxicity in animals, it progresses through Phase I testing with healthy volunteers, Phase II learning trials to establish proof-of-mechanism and dose, and Phase III confirmatory trials to demonstrate efficacy and safety in larger populations. Phase III is followed by Food and Drug Administration review and, if appropriate, market access. Trial populations include cognitively normal at-risk participants in prevention trials, mildly impaired participants with biomarker evidence of AD in prodromal AD trials, and subjects with cognitive and functional impairment in AD dementia trials. Biomarkers are critical in trials of DMTs, assisting in participant characterization and diagnosis, target engagement and proof-of-pharmacology, demonstration of disease-modification, and monitoring side effects. Clinical trial designs include randomized, parallel group; delayed start; staggered withdrawal; and adaptive. Lessons learned from completed trials inform future trials and increase the likelihood of success.

Insights into globalization: comparison of patient characteristics and disease progression among geographic regions in a multinational Alzheimer's disease clinical program

BACKGROUND

Globalization of clinical trials has important consequences for trial planning and interpretation. This study investigated heterogeneity in patient characteristics and outcomes among world regions in the global idalopirdine Phase 3 clinical program.

METHODS

Data were pooled from three 24-week randomized controlled trials in patients aged ≥ 50 years with mild-to-moderate Alzheimer's disease (AD) (n = 2506). Patients received idalopirdine (10, 30, or 60 mg/day) or placebo, added to cholinesterase inhibitor treatment. Patients were categorized into the following regions: Eastern Europe/Turkey (n = 759), Western Europe/Israel (n = 709), USA/Canada (n = 444), South America/Mexico (n = 361), Asia (n = 134), and Australia/South Africa (n = 99). For each region, operational characteristics, baseline demographic and clinical characteristics, adverse events, and mean change from baseline to week 24 in clinical rating scale scores (placebo group only) were summarized using descriptive statistics.

RESULTS

Completion rates were 0.86-0.90 in all regions. Heterogeneity among global regions was evident. Protocol deviations were twice as common in South America/Mexico as in USA/Canada (2.64 vs 1.35 per patient screened). Educational level ranged from 9.2 years in South America/Mexico to 13.4 years in USA/Canada. APOE ε4 carriage was 80.6% in Australia/South Africa, 63.1% in Western Europe/Israel, and < 60% in other regions. Screening Mini-Mental State Examination scores were higher in Eastern Europe/Turkey (18.0) and USA/Canada (17.5) than in other regions (16.9-17.1). Baseline AD Assessment Scale-Cognitive subscale (ADAS-Cog) scores ranged from 24.3 in USA/Canada to 27.2 in South America/Mexico. Baseline AD Cooperative Study-Activities of Daily Living, 23-item version (ADCS-ADL23) scores ranged from 58.5 in USA/Canada to 53.5 in Eastern Europe/Turkey. In the placebo group, adverse events were 1.6-1.7 times more common in Western Europe/Israel, USA/Canada, and Australia/South Africa than in Eastern Europe/Turkey. On the ADAS-Cog, Australia/South Africa and Western Europe/Israel showed the most worsening among patients receiving placebo (1.56 and 1.40 points, respectively), whereas South America/Mexico showed an improvement (-0.71 points). All regions worsened on the ADCS-ADL23, from -3.21 points in Western Europe/Israel to -0.59 points in Eastern Europe/Turkey.

CONCLUSIONS

Regional heterogeneity-in terms of study conduct, patient characteristics, and outcomes-exists, and should be accounted for, when planning and conducting multinational AD clinical trials.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01955161 . Registered on 27 September 2013. ClinicalTrials.gov, NCT02006641 . Registered on 5 December 2013. ClinicalTrials.gov, NCT02006654 . Registered on 5 December 2013.

Representativeness of European clinical trial populations in mild Alzheimer's disease dementia: a comparison of 18-month outcomes with real-world data from the GERAS observational study

Background

Comparison of disease progression between placebo-group patients from randomised controlled trials (RCTs) and real-world patients can aid in assessing the generalisability of RCT outcomes. This analysis compared outcomes between community-dwelling patients with mild Alzheimer’s disease (AD) dementia from two RCTs (pooled European (EU) data from EXPEDITION and EXPEDITION 2) and similar patients from the EU GERAS observational study.

Methods

Data from placebo-group patients with mild AD dementia from the RCTs (EU countries only) were compared with data from GERAS patients with mild AD dementia. Between-group differences for changes over 18 months were analysed for cognition, functioning, neuropsychiatric symptoms, health-related quality of life (HRQoL) and caregiver time using propensity score-adjusted models. A sensitivity analysis compared EU/North American (EU/NA) EXPEDITION patients with GERAS patients.

Results

EU EXPEDITION patients (n = 168) were younger than GERAS patients (n = 566) (mean (standard deviation, SD) age 71.9 (7.4) versus 77.3 (6.9) years; p < 0.001) and were more likely to use AD treatment (95% versus 84%; p < 0.001). Cognitive performance was similar at baseline in both populations, although GERAS patients showed greater functional impairment (p = 0.005) and lower HRQoL (p < 0.05). At 18 months, no statistically significant differences between EXPEDITION (n = 133) and GERAS (n = 417) patients were observed for changes in cognitive, functional, neuropsychiatric and HRQoL outcomes. Least squares mean (95% confidence interval) change in caregiver time (hours/month) spent on instrumental activities of daily living (iADL; 29.22 (19.16, 39.27) versus 3.20 (−11.89, 18.28), p = 0.001) and supervision (66.59 (47.49, 85.69) versus 3.04 (−25.39, 31.48), p < 0.001) showed greater increases in GERAS than EXPEDITION. In the sensitivity analysis, changes in neuropsychiatric and HRQoL scores and caregiver time spent on basic ADL were also significantly greater in GERAS than in EU/NA EXPEDITION patients.

Conclusions

Patients with mild AD dementia participating in the EU EXPEDITION RCTs and the GERAS observational study showed a similar decline in cognitive, functional and neuropsychiatric symptoms over 18 months, whereas changes in caregiver time measures were significantly greater in GERAS. Results indicate the importance of using similar regions when comparing real-world and RCT data.

Trial registration

ClinicalTrials.gov NCT00905372 EXPEDITION. Registered 18 May 2009.

ClinicalTrials.gov NCT00904683 EXPEDITION 2. Registered 18 May 2009.

Experimental study on the neurotoxic effect of β-amyloid on the cytoskeleton of PC12 cells

The aim of the present study was to establish a cell model of Alzheimer's disease (AD) and investigate the neurotoxic effects of β-amyloid (Aβ) on the cytoskeleton. PC12 cells were cultured and treated with Aβ_25-35, and cell survival was analyzed with the MTT assay. Cell apoptosis was visualized using 4′,6-diamidino-2-phenylindole staining and the terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. Immunocytochemistry and phalloidin staining were used to label the cytoskeleton of PC12 cells. Aβ_25-35 was found to induce PC12 cell apoptosis in a dose-dependent manner (P<0.05). Moreover, Aβ_25-35 also caused dose-dependent disintegration of the cytoskeleton (P<0.05). Therefore, the PC12 cell cytoskeleton was found to be sensitive to Aβ_25-35 neurotoxicity. The disintegration of the cytoskeleton is likely an important pathological alteration in AD, and Aβ is a key molecule involved in AD pathogenesis.

The Alzheimer's Disease Neuroimaging Initiative 3: Continued innovation for clinical trial improvement

INTRODUCTION

The overall goal of the Alzheimer's Disease Neuroimaging Initiative (ADNI) is to validate biomarkers for Alzheimer's disease (AD) clinical trials. ADNI-3, which began on August 1, 2016, is a 5-year renewal of the current ADNI-2 study.

METHODS

ADNI-3 will follow current and additional subjects with normal cognition, mild cognitive impairment, and AD using innovative technologies such as tau imaging, magnetic resonance imaging sequences for connectivity analyses, and a highly automated immunoassay platform and mass spectroscopy approach for cerebrospinal fluid biomarker analysis. A Systems Biology/pathway approach will be used to identify genetic factors for subject selection/enrichment. Amyloid positron emission tomography scanning will be standardized using the Centiloid method. The Brain Health Registry will help recruit subjects and monitor subject cognition.

RESULTS

Multimodal analyses will provide insight into AD pathophysiology and disease progression.

DISCUSSION

ADNI-3 will aim to inform AD treatment trials and facilitate development of AD disease-modifying treatments.

Sex and gender differences in the treatment of Alzheimer's disease: A systematic review of randomized controlled trials

In recent years, epidemiological, clinical, and biological evidence has drawn the attention on the influence of sex and gender on Alzheimer's disease (AD). Nevertheless, not enough attention has been paid to their impact on treatment outcomes. The present study is aimed at systematically retrieve, review and discuss data coming from available randomized placebo-controlled trials (RCTs) on currently marketed treatments for AD (i.e., cholinesterase inhibitors [ChEIs] and memantine) in order to describe possible sex and gender differences in their efficacy, safety and tolerability. A systematic review of literature was performed. None of the retrieved studies reported data on the efficacy, safety and tolerability of considered medications separately in male and female patients with AD. We thus analyzed 48 excluded studies of potential interest, that is, almost all of the currently available trials on the four considered drugs. Nearly all the considered RCTs recruited a larger number of female participants to mirror the sexually unbalanced prevalence of AD. Only two studies took into account the potential influence of sex and gender on treatment efficacy, reporting no significant differences between men and women. None of the studies investigated potential sex and gender differences in the safety and tolerability of the four considered treatments. The existence of sex and gender differences in the efficacy and tolerability of ChEIs and memantine in AD has, to date, drawn limited to no attention. However, a considerable amount of data, with an adequate representativeness in terms of sex/gender distribution, seem to be already available for dedicated analyses on this topic. A greater effort should be made to collect and report data on those factors interacting with sex and gender that may significantly influence clinical manifestations, outcomes, and trajectories over time of AD patients.

Re-Engineering Alzheimer Clinical Trials: Global Alzheimer's Platform Network

Alzheimer's disease (AD) drug development is costly, time-consuming, and inefficient. Trial site functions, trial design, and patient recruitment for trials all require improvement. The Global Alzheimer Platform (GAP) was initiated in response to these challenges. Four GAP work streams evolved in the US to address different trial challenges: 1) registry-to-cohort web-based recruitment; 2) clinical trial site activation and site network construction (GAP-NET); 3) adaptive proof-of-concept clinical trial design; and 4) finance and fund raising. GAP-NET proposes to establish a standardized network of continuously funded trial sites that are highly qualified to perform trials (with established clinical, biomarker, imaging capability; certified raters; sophisticated management system. GAP-NET will conduct trials for academic and biopharma industry partners using standardized instrument versions and administration. Collaboration with the Innovative Medicines Initiative (IMI) European Prevention of Alzheimer's Disease (EPAD) program, the Canadian Consortium on Neurodegeneration in Aging (CCNA) and other similar international initiatives will allow conduct of global trials. GAP-NET aims to increase trial efficiency and quality, decrease trial redundancy, accelerate cohort development and trial recruitment, and decrease trial costs. The value proposition for sites includes stable funding and uniform training and trial execution; the value to trial sponsors is decreased trial costs, reduced time to execute trials, and enhanced data quality. The value for patients and society is the more rapid availability of new treatments for AD.