A large number of promising candidate disease-modifying treatments for Alzheimer disease (AD) continue to advance into phase II and phase III testing. However, most completed trials have failed to ...demonstrate efficacy, and there is growing concern that methodologic difficulties may contribute to these clinical trial failures. The optimal time to intervene with such treatments is probably in the years prior to the onset of dementia, before the neuropathology has progressed to the advanced stage corresponding to clinical dementia.
An international task force of individuals from academia, industry, nonprofit foundations, and regulatory agencies was convened to discuss optimal trial design in early (predementia) AD.
General consensus was reached on key principles involving the scope of the AD diagnosis, the selection of subjects for trials, outcome measures, and analytical methods.
A consensus has been achieved in support of the testing of candidate treatments in the early (predementia) AD population.
To identify a cognitive composite that is sensitive to tracking preclinical Alzheimer's disease decline to be used as a primary end point in treatment trials.
We capitalized on longitudinal data ...collected from 1995 to 2010 from cognitively unimpaired presenilin 1 (PSEN1) E280A mutation carriers from the world's largest known early-onset autosomal dominant Alzheimer's disease kindred to identify a composite cognitive test with the greatest statistical power to track preclinical Alzheimer's disease decline and estimate the number of carriers age 30 years and older needed to detect a treatment effect in the Alzheimer's Prevention Initiative's (API) preclinical Alzheimer's disease treatment trial. The mean-to-standard-deviation ratios (MSDRs) of change over time were calculated in a search for the optimal combination of 1 to 7 cognitive tests/subtests drawn from the neuropsychological test battery in cognitively unimpaired mutation carriers during a 2- and 5-year follow-up period (n = 78 and 57), using data from noncarriers (n = 31 and 56) during the same time period to correct for aging and practice effects. Combinations that performed well were then evaluated for robustness across follow-up years, occurrence of selected items within top-performing combinations, and representation of relevant cognitive domains.
The optimal test combination included Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Recall, CERAD Boston Naming Test (high frequency items), Mini-Mental State Examination (MMSE) Orientation to Time, CERAD Constructional Praxis, and Raven's Progressive Matrices (Set A), with an MSDR of 1.62. This composite is more sensitive than using either the CERAD Word List Recall (MSDR = 0.38) or the entire CERAD-Col battery (MSDR = 0.76). A sample size of 75 cognitively normal PSEN1 E280A mutation carriers aged 30 years and older per treatment arm allows for a detectable treatment effect of 29% in a 60-month trial (80% power, P = .05).
We have identified a composite cognitive test score representing multiple cognitive domains that, compared to the most sensitive single test item, has improved power to track preclinical Alzheimer's disease decline in autosomal dominant Alzheimer's disease mutation carriers and to evaluate preclinical Alzheimer's disease treatments. This API composite cognitive test score will be used as the primary end point in the first API trial in cognitively unimpaired autosomal dominant Alzheimer's disease carriers within 15 years of their estimated age at clinical onset. We have independently confirmed our findings in a separate cohort of cognitively healthy older adults who progressed to the clinical stages of late-onset Alzheimer's disease, described in a separate report, and continue to refine the composite in independent cohorts and compared with other analytic approaches.
As research evolves in prodromal AD, the need to validate sufficiently sensitive outcome measures, e.g. the Alzheimer’s Disease Composite Score (ADCOMS) is clear. In the LipiDiDiet randomized trial ...in prodromal AD, cognitive decline in the study population was much less than expected in the timeframe studied. While the primary composite endpoint was insufficiently sensitive to detect a difference in the modified intention to treat population, the per-protocol population showed less decline in the active than the control group, indicating better treatment effects with regular product intake. These results were further strengthened by significant benefits on secondary endpoints of cognition and function, and brain atrophy. The present post-hoc analysis investigated whether ADCOMS could detect a difference between groups in the LipiDiDiet population (138 active, 140 control). The estimated mean change in ADCOMS from baseline (standard error) was 0.085 (0.018) in the active and 0.133 (0.018) in the control group; estimated mean treatment difference −0.048 (95% confidence intervals −0.090, −0.007; p=0.023), or 36% less decline in the active group. This suggests ADCOMS identified the cognitive and functional benefits observed previously, confirming the sensitivity of this composite measure.
Introduction
The LipiDiDiet trial investigates the effects of the specific multinutrient combination Fortasyn Connect on cognition and related measures in prodromal Alzheimer's disease (AD). Based on ...previous results we hypothesized that benefits increase with long‐term intervention.
Methods
In this randomized, double‐blind, placebo‐controlled trial, 311 people with prodromal AD were recruited using the International Working Group‐1 criteria and assigned to active product (125 mL once‐a‐day drink) or an isocaloric, same tasting, placebo control drink. Main outcome was change in cognition (Neuropsychological Test Battery NTB 5‐item composite). Analyses were by modified intention‐to‐treat, excluding (ie, censoring) data collected after the start of open‐label active product and/or AD medication.
Results
Of the 382 assessed for eligibility, 311 were randomized, of those 162 participants completed the 36‐month study, including 81 with 36‐month data eligible for efficacy analysis. Over 36 months, significant reductions in decline were observed for the NTB 5‐item composite (−60%; between‐group difference 0.212 95% confidence interval: 0.044 to 0.380; P = 0.014), Clinical Dementia Rating‐Sum of Boxes (−45%; P = 0.014), memory (−76%; P = 0.008), and brain atrophy measures; small to medium Cohen's d effect size (0.25–0.31) similar to established clinically relevant AD treatment.
Discussion
This multinutrient intervention slowed decline on clinical and other measures related to cognition, function, brain atrophy, and disease progression. These results indicate that intervention benefits increased with long‐term use.
Nutrition is an important modifiable risk factor in Alzheimer's disease. Previous trials of the multinutrient Fortasyn Connect showed benefits in mild Alzheimer's disease dementia. LipiDiDiet ...investigated the effects of Fortasyn Connect on cognition and related measures in prodromal Alzheimer's disease. Here, we report the 24-month results of the trial.
LipiDiDiet was a 24-month randomised, controlled, double-blind, parallel-group, multicentre trial (11 sites in Finland, Germany, the Netherlands, and Sweden), with optional 12-month double-blind extensions. The trial enrolled individuals with prodromal Alzheimer's disease, defined according to the International Working Group (IWG)-1 criteria. Participants were randomly assigned (1:1) to active product (125 mL once-a-day drink containing Fortasyn Connect) or control product. Randomisation was computer-generated centrally in blocks of four, stratified by site. All study personnel and participants were masked to treatment assignment. The primary endpoint was change in a neuropsychological test battery (NTB) score. Analysis was by modified intention to treat. Safety analyses included all participants who consumed at least one study product dose. This trial is registered with the Dutch Trial Register, number NTR1705.
Between April 20, 2009, and July 3, 2013, 311 of 382 participants screened were randomly assigned to the active group (n=153) or control group (n=158). Mean change in NTB primary endpoint was −0·028 (SD 0·453) in the active group and −0·108 (0·528) in the control group; estimated mean treatment difference was 0·098 (95% CI −0·041 to 0·237; p=0·166). The decline in the control group was less than the prestudy estimate of −0·4 during 24 months. 66 (21%) participants dropped out of the study. Serious adverse events occurred in 34 (22%) participants in the active group and 30 (19%) in control group (p=0·487), none of which were regarded as related to the study intervention.
The intervention had no significant effect on the NTB primary endpoint over 2 years in prodromal Alzheimer's disease. However, cognitive decline in this population was much lower than expected, rendering the primary endpoint inadequately powered. Group differences on secondary endpoints of disease progression measuring cognition and function and hippocampal atrophy were observed. Further study of nutritional approaches with larger sample sizes, longer duration, or a primary endpoint more sensitive in this pre-dementia population, is needed.
European Commission 7th Framework Programme.
Antiretroviral medications that are used as prophylaxis can prevent acquisition of human immunodeficiency virus type 1 (HIV-1) infection. However, in clinical trials among African women, the ...incidence of HIV-1 infection was not reduced, probably because of low adherence. Longer-acting methods of drug delivery, such as vaginal rings, may simplify use of antiretroviral medications and provide HIV-1 protection.
We conducted a phase 3, randomized, double-blind, placebo-controlled trial of a monthly vaginal ring containing dapivirine, a non-nucleoside HIV-1 reverse-transcriptase inhibitor, involving women between the ages of 18 and 45 years in Malawi, South Africa, Uganda, and Zimbabwe.
Among the 2629 women who were enrolled, 168 HIV-1 infections occurred: 71 in the dapivirine group and 97 in the placebo group (incidence, 3.3 and 4.5 per 100 person-years, respectively). The incidence of HIV-1 infection in the dapivirine group was lower by 27% (95% confidence interval CI, 1 to 46; P=0.046) than that in the placebo group. In an analysis that excluded data from two sites that had reduced rates of retention and adherence, the incidence of HIV-1 infection in the dapivirine group was lower by 37% (95% CI, 12 to 56; P=0.007) than that in the placebo group. In a post hoc analysis, higher rates of HIV-1 protection were observed among women over the age of 21 years (56%; 95% CI, 31 to 71; P<0.001) but not among those 21 years of age or younger (-27%; 95% CI, -133 to 31; P=0.45), a difference that was correlated with reduced adherence. The rates of adverse medical events and antiretroviral resistance among women who acquired HIV-1 infection were similar in the two groups.
A monthly vaginal ring containing dapivirine reduced the risk of HIV-1 infection among African women, with increased efficacy in subgroups with evidence of increased adherence. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01617096 .).
Atmospheric CO2 concentration (C(a)) continues to rise. An imperative exists, therefore, to elucidate the interactive effects of elevated C(a) and drought on plant water relations of wheat (Triticum ...aestivum L.). A spring wheat (cv. Yecora Rojo) crop was exposed to ambient (Control: 370 micromol mol(-1)) and free-air CO2 enrichment (FACE: ambient + 180 micromol mol(-1)) under ample (Wet), and reduced (Dry), water supplies (100 and 50% replacement of evapotranspiration, respectively) over a 2-yr study. Our objective was to characterize and quantify the responses of 26 edaphic, gas exchange, water relations, carbohydrate pool dynamics, growth, and development parameters to rising C(a) and drought. Increasing C(a) minimized the deleterious effects of soil-water depletion by increasing drought avoidance (i.e., lower stomatal conductance and transpiration rate, and growth and development of a more robust root system) and drought tolerance (i.e., enhanced osmoregulation and adaptation of tissue) mechanisms, resulting in a 30% reduction in water stress-induced midafternoon depressions in net assimilation rate. An elevated C(a)-based increase in daily and seasonal carbon gain resulted in a positive feedback between source capacity (shoots) and sink demand (roots). Devoid of a concomitant rise in global temperature resulting from the rise in C(a), improved water relations for a herbaceous, cool-season, annual, C3 cereal monocot grass (i.e., wheat) are anticipated in a future high-CO2 world. These findings are applicable to other graminaceous species of a similar function-type as wheat common to temperate zone grassland prairies and savannas, especially under dryland conditions.
Summary Background The amyloid-β peptide Aβ42 has been implicated in the pathogenesis of Alzheimer's disease (AD). We aimed to test the effects of tarenflurbil, a selective Aβ42 -lowering agent ...(SALA), on cognition and function in patients with mild to moderate AD. Methods 210 patients living in the community who had a mini-mental state examination (MMSE) score of 15–26 were randomly assigned to receive tarenflurbil twice per day (400 mg n=69 or 800 mg n=70) or placebo (n=71) for 12 months in a phase II, multicentre, double-blind study. Primary efficacy outcomes were the AD assessment scale cognitive subscale (ADAS-cog), the Alzheimer's Disease Cooperative Study activities of daily living scale (ADCS-ADL), and the clinical dementia rating sum of boxes (CDR-sb). In a 12-month extended treatment phase, patients who had received tarenflurbil continued to receive the same dose, and patients who had received placebo were randomly assigned to tarenflurbil at 800 mg or 400 mg twice per day. Primary efficacy analyses were done by intention to treat. This trial is registered with Health Canada (084527) and the Medicines and Healthcare products Regulatory Agency in the UK (20365/0001/A 69316). Findings A prespecified interaction analysis revealed that patients with mild AD (baseline MMSE 20–26) and moderate AD (baseline MMSE 15–19) responded differently to tarenflurbil in the ADAS-cog and the ADCS-ADL (p≥0·10); therefore, these groups were analysed separately. Patients with mild AD in the 800 mg tarenflurbil group had lower rates of decline than did those in the placebo group in activities of daily living (ADCS-ADL difference in slope 3·98 95% CI 0·33 to 7·62 points per year, effect size reduction from placebo decline rate 46·4%, Cohen's d 0·45; p=0·033) and global function (CDR-sb difference −0·80 −1·57 to −0·03 points per year, effect size 35·7%, Cohen's d 0·42; p=0·042); slowing of cognitive decline did not differ significantly (ADAS-cog difference −1·36 −4·07 to 1·36 points per year, effect size 33·7%, Cohen's d 0·20; p=0·327). In patients with moderate AD, 800 mg tarenflurbil twice per day had no significant effects on ADCS-ADL and ADAS-cog and had a negative effect on CDR-sb (−52%, Cohen's d −1·08; p=0·003). The most common adverse events were diarrhoea (in seven, nine, and five patients in the 800 mg, 400 mg, and placebo groups, respectively), nausea (in seven, seven, and four patients), and dizziness (in five, nine, and four patients). Patients with mild AD who were in the 800 mg tarenflurbil group for 24 months had lower rates of decline for all three primary outcomes than did patients who were in the placebo group for months 0–12 and a tarenflurbil group for months 12–24 (all p<0·001), and had better outcomes than did patients who were in the placebo group for months 0–12 and the 800 mg tarenflurbil group for months 12–24 (all p<0·05). Interpretation 800 mg tarenflurbil twice per day was well tolerated for up to 24 months of treatment, with evidence of a dose-related effect on measures of daily activities and global function in patients with mild AD. Funding Myriad Pharmaceuticals.
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