Leah Burns

Injury markers predict time to dementia in subjects with MCI and amyloid pathology

Objectives: Alzheimer disease (AD) can now be diagnosed in subjects with mild cognitive impairment (MCI) using biomarkers. However, little is known about the rate of decline in those subjects. In this cohort study, we aimed to assess the conversion rate to dementia and identify prognostic markers in subjects with MCI and evidence of amyloid pathology. Methods: We pooled subjects from the VU University Medical Center Alzheimer Center and the Development of Screening Guidelines and Criteria for Predementia Alzheimers Disease (DESCRIPA) study. We included subjects with MCI, an abnormal level of β-amyloid1−42 (Aβ1–42) in the CSF, and at least one diagnostic follow-up visit. We assessed the effect of APOE genotype, CSF total tau (t-tau) and tau phosphorylated at threonine 181 (p-tau) and hippocampal volume on time to AD-type dementia using Cox proportional hazards models and on decline on the Mini-Mental State Examination (MMSE) using linear mixed models. Results: We included 110 subjects with MCI with abnormal CSF Aβ1–42 and a mean MMSE score of 26.3 ± 2.8. During a mean follow-up of 2.2 ± 1.0 (range 0.4–5.0) years, 63 subjects (57%) progressed to AD-type dementia. Abnormal CSF t-tau (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.1–4.6, p = 0.03) and CSF p-tau (HR 3.5, 95% CI 1.3–9.2, p = 0.01) concentration and hippocampal atrophy (HR 2.5, 95% CI 1.1–5.6, p = 0.02) predicted time to dementia. For subjects with both abnormal t-tau concentration and hippocampal atrophy, HR was 7.3 (95% CI 1.0–55.9, p = 0.06). Furthermore, abnormal CSF t-tau and p-tau concentrations and hippocampal atrophy predicted decline in MMSE score. Conclusions: In subjects with MCI and evidence of amyloid pathology, the injury markers CSF t-tau and p-tau and hippocampal atrophy can predict further cognitive decline.

Test sequence of CSF and MRI biomarkers for prediction of AD in subjects with MCI

Our aim was to identify the best diagnostic test sequence for predicting Alzheimers disease (AD)-type dementia in subjects with mild cognitive impairment (MCI) using cerebrospinal fluid (CSF) and magnetic resonance imaging (MRI) biomarkers. We selected 153 subjects with mild cognitive impairment from a multicenter memory clinic-based cohort. We tested the CSF beta amyloid (Aβ)1-42/tau ratio using enzyme-linked immunosorbent assay (ELISA) and hippocampal volumes (HCVs) using the atlas-based learning embeddings for atlas propagation (LEAP) method. Outcome measure was progression to AD-type dementia in 2 years. At follow-up, 48 (31%) subjects converted to AD-type dementia. In multivariable analyses, CSF Aβ1-42/tau and HCV predicted AD-type dementia regardless of apolipoprotein E (APOE) genotype and cognitive scores. Test sequence analyses showed that CSF Aβ1-42/tau increased predictive accuracy in subjects with normal HCV (p < 0.001) and abnormal HCV (p = 0.025). HCV increased predictive accuracy only in subjects with normal CSF Aβ1-42/tau (p = 0.014). Slope analyses for annual cognitive decline yielded similar results. For selection of subjects for a prodromal AD trial, the best balance between sample size and number of subjects needed to screen was obtained with CSF markers. These results provide further support for the use of CSF and magnetic resonance imaging biomarkers to identify prodromal AD.

Screening for predementia AD: Time-dependent operating characteristics of episodic memory tests

Objective: Data from the Einstein Aging Study (EAS) were used to prospectively evaluate the free recall score from the Free and Cued Selective Reminding Test (FCSRT-FR) and Logical Memory I immediate recall (LM-IR) subtest of the Wechsler Memory Scale–Revised for prediction of incident Alzheimer disease (AD) dementia among individuals from a community-based cohort with memory complaints. Methods: Analyses included 854 participants, age ≥70 years, who initially had no dementia, and had memory complaints. Clinic evaluations were completed annually and AD dementia was diagnosed using standard criteria (n = 86 cases; average follow-up 4.1 years). Time-dependent receiver operating characteristic analysis was used to evaluate the prognostic ability of FCSRT-FR and LM-IR for incident AD over various durations of follow-up. Results: For identifying those with memory complaints who will develop incident AD dementia over 2–4 years, the FCSRT-FR had better operating characteristics than LM-IR. APOE ε4 status, age, and education did not affect cut points; however, positive predictive values were higher among APOE ε4-positive individuals. Conclusions: For follow-up intervals of 2–4 years, the FCSRT-FR is more predictive than the LM-IR for identifying individuals with memory complaints who will develop incident AD. APOE ε4 status improves positive predictive value, but does not affect the choice of optimal cuts.

The epidemiology of Alzheimer’s disease: Laying the foundation for drug design, conduct, and analysis of clinical trials

Epidemiological studies increasingly inform Alzheimers disease (AD) public health impact, prevention strategies, drug targets, therapeutic interventions, and clinical trial design. For this reason, the Alzheimers Association Research Roundtable convened an international group of AD experts with experience in conducting both observational and clinical trials for a meeting on October 19 and 20, 2010, in Washington, DC, to discuss the role of epidemiologic studies in AD research and therapeutic advances. Topics included wellness markers and risk factors, with a focus on special populations such as those at elevated risk, super agers, and underserved populations. Discussions also highlighted lessons learned from observational studies of aging, cardiovascular disease, and other disease areas, as well as how new technologies have enabled the gathering of data relevant to drug development and clinical trial conduct.

Impact of early intervention and disease modification in patients with predementia Alzheimer’s disease: a Markov model simulation

Background: Early screenings involving biomarkers and use of potential disease-modifying therapies (DMTs) may have significant humanistic implications for treatment strategies in Alzheimer’s disease. Methods: Markov models simulated transitions of patient cohorts beginning in predementia, a hypothetical early stage of Alzheimer’s disease marked by objective cognitive impairment/memory complaints without functional impairment, and followed for 10 years. Hypothetical cohorts of 10,000 patients included those who were treated with standard of care (donepezil) upon reaching mild–moderate Alzheimer’s disease, a DMT in predementia, and a DMT in mild-moderate Alzheimer’s disease. Transition probabilities were based on data from the Alzheimer’s Disease Neuroimaging Initiative and published clinical data, and estimated for the hypothetical DMT. In each disease stage (predementia, mild, moderate, or severe), time was computed and costs were estimated using literature review and published data, and published data provided mortality rates. The impact of screening was evaluated using positive predictive value (patients identified as predementia truly at risk for transition to dementia). Results: Earlier treatment yielded modest gains in total life-years; however, the distribution was skewed towards milder disease. Assuming a 25% reduction in the annual risk of progression, treating predementia patients with DMT increased life-years in predementia to mild states on average from 3.2 to 4.2, while life-years spent in moderate-to-severe Alzheimer’s disease decreased from 2.6 to 2.2. Average time in the community increased from 4.4 to 5.4 years, while time in long-term care declined from 1.3 to 0.9 years. This impact grows as the advantage of the novel agent increases. Screening accuracy had significant implications for cost-effectiveness. Conclusion: If screening can accurately identify predementia patients at risk for progression, earlier treatment with DMTs has the potential benefit to patients of prolonging time in milder disease, reducing time spent with more severe disease, increasing time in the community, and reducing time in long-term care.

Comparison of "Word" vs. "Picture" version of the Free and Cued Selective Reminding Test (FCSRT) in older adults

This study examined the psychometric relationship between the Word and Picture versions of the Free and Cued Selective Reminding Test (FCSRT) and developed an equation for score conversion.

Value-based assessment of pharmacodiagnostic testing from early stage development to real-world use.

Disease etiology may be regarded as a consequence of both genotypic and biochemical phenomena, which impact individual patients in different ways. Disease prognosis, beneficial treatment response, and susceptibility to adverse drug effects are often intimately tied to individual biology. Clinical and genetic biomarkers applied individually or in concert are increasingly used to stratify patient populations in terms of prognosis, therapeutic benefit, or safety. As a result, clinical trialists are challenged to design studies that reflect these determinants of outcome, to optimize the patients eventual clinical course both in the trial and in actual practice. These designs are informed both by preclinical studies and by real-world research that can establish proof of concept for a novel biomarker and provide a basic understanding of the relationship between biomarker and clinical outcome. As clinical and real-world studies unfold, a deeper understanding of the nature of the biomarker and its potential uses in drug development is gained. Specifically, one can eventually define the biomarker as prognostic (i.e., predicts disease progression), predictive (predicts treatment response or adverse outcome(s)), or exhibiting both prognostic and predictive properties. One must further validate the performance of these emerging biomarkers, again in both the trial and real-world environments. The eventual adoption of the biomarker as a useful pharmacodiagnostic test is premised upon this early translational research. In this article, the development and validation of predictive and prognostic biomarkers is discussed by using selected examples that highlight factors contributing to the valuation of biomarkers and their application to personalized medicine in the real world.

Treatment patterns in patients with advanced breast cancer who were exposed to an anthracycline, a taxane, and capecitabine: A descriptive report

OBJECTIVE The aim of this work was to analyze chemotherapy treatment patterns in patients with advanced breast cancer who had been previously exposed to an anthracycline, a taxane, and capecitabine. METHODS This retrospective cohort study used medical and pharmacy administrative claims with health-plan enrollment data and medical-record review from a large, US-based health insurer database, the HealthCore Integrated Research Database. Women were included if they were aged > or =18 years at the initial breast cancer diagnosis between January 1999 and July 2005 and had received all 3 drug classes of interest, as well as an initial diagnosis of American Joint Committee on Cancer stage I to III breast cancer with metastatic recurrence or an initial diagnosis of stage IV disease. Information about demographics, clinical and pathologic characteristics, survival, and treatments were obtained from computerized data and medical record review. Descriptive analyses were conducted to characterize the treatment patterns. RESULTS One hundred forty-four women with advanced breast cancer were identified. Patients ranged in age from 28 to 76 years, with a mean (SD) age of 48.2 (9.1) years, and with 54 patients (37.5%) aged 40 to 49 years and 48 patients (33.3%) aged 50 to 59 years at the time of initial diagnosis. Ninety-three patients (64.6%) were white, 15 (10.4%) were black, 7 (4.9%) were Hispanic, and 4 (2.8%) were Asian. Overall, 89 patients (61.8%) received > or =1 additional chemotherapy regimen after exposure to all 3 chemotherapy agents of interest; 55 (38.2%) received > or =2 additional regimens. A variety of chemotherapeutic regimens were prescribed; 14 monotherapy regimens and 37 combination therapy regimens were used. The most common regimens (both as single agents and combination therapy) included gemcitabine, vinorelbine, or retreatment with a taxane. Of the 89 patients who received > or =1 retreatment, 7 (7.9%) were retreated with anthracycline, 12 (13.5%) with a taxane, and 9 (10.1%) with capecitabine. For first and second treatment after exposure to all 3 agents of interest, the most common single-agent regimens were gemcitabine (first: 17 patients [19.1%]; second: 9 patients [16.4%]) and vinorelbine (first: 14 patients [15.7%]; second: 9 patients [16.4%]). The most common combination therapies for first retreatment were carboplatin based (6 patients [6.7%]). CONCLUSIONS Of these patients with advanced breast cancer, 61.8% received > or =1 additional chemotherapy regimen after previous treatment with an anthracycline, a taxane, and capecitabine. The variety of agents prescribed suggests a lack of standard of care. Rigorous clinical effectiveness studies of common regimens in heavily pretreated and chemotherapy-resistant populations with breast cancer are warranted.

Effectiveness and Safety of Apixaban versus Warfarin as Outpatient Treatment of Venous Thromboembolism in U.S. Clinical Practice

In the AMPLIFY clinical trial, apixaban was non-inferior to warfarin plus subcutaneous enoxaparin bridge therapy in the treatment of acute venous thromboembolism (VTE) and was associated with significantly less bleeding. This study evaluated their comparative effectiveness and safety in routine clinical practice. A matched-cohort design and data from four U.S. private health care claims databases were employed. Study population comprised patients who initiated outpatient treatment with apixaban versus warfarin (plus parenteral anticoagulant bridge therapy) within 30 days of their initial VTE episode; apixaban and warfarin patients were matched on age, characteristics of VTE episode, study database and propensity score. Major bleeding, clinically relevant non-major (CRNM) bleeding and recurrent VTE during the 180-day (maximum) follow-up period were compared using shared frailty models. During mean follow-up of 143 days among apixaban patients ( n  = 17,878) and 152 days among warfarin patients ( n  = 17,878), incidence proportions for apixaban versus warfarin, respectively, were 1.7% versus 2.3% for major bleeding, 7.0% versus 9.4% for CRNM bleeding and 2.3% versus 2.9% for recurrent VTE. In shared frailty models, risks of major bleeding (hazard ratio [HR] = 0.75, 95% confidence interval [CI] = 0.64–0.87), CRNM bleeding (HR = 0.77, 95% CI = 0.71–0.83) and recurrent VTE (HR = 0.80, 95% CI = 0.70–0.91) were lower for apixaban versus warfarin. In this large-scale evaluation of VTE patients receiving outpatient treatment with apixaban or warfarin in U.S. clinical practice, risks of major bleeding, CRNM bleeding and recurrent VTE were significantly lower among patients who received apixaban.

The Gamma Secretase Inhibitor, BMS-708163 Increases Alpha Secretase Abeta Peptide Cleavage Fragments and Decreases the Gamma Secretase Abeta Peptide 1-34 Fragment in Cerebrospinal Fluid

to investigate the role of the innate immune system inAlzheimer’s disease (AD) bymeasuring complement factors in cerebrospinal fluid (CSF) of subjects with mild cognitive impairment (MCI), AD and other dementias (oDem).Methods: We selected healthy controls (n1⁄4 19, age1⁄4 63, MMSE1⁄4 29.1), subjects with MCI (n 1⁄4 56, age 1⁄4 70, MMSE 1⁄4 26.9), AD (n 1⁄4 45, age 1⁄4 72, MMSE 1⁄4 22.9) and oDem (n 1⁄4 31, age 1⁄4 69 MMSE 1⁄4 24.1) from the EDAR study (www.edarstudy.eu). We measured C3a, central to the classical, alternative and lectin complement pathways, C5a involved in the lytic complement pathway, and the soluble C5b-9 terminal complement complex (TCC). We also measured in CSF abeta 1-42, total tau, and serum amyloid P (SAP, an acute response protein which activates complement). We compared groups and correlated complement markers with other biomarkers, neuropsychological markers, andmarkers of functional impairment using non-parametric tests.Results: Complement data are shown in the table. C3a was decreased by 50-60% in subjects with MCI, AD, and oDem relative to controls (p < 0.003 all comparisons). C5a was increased 3-6 fold in AD relative to controls (p 1⁄4 0.077), MCI (p1⁄4 0.016), and oDem(p1⁄4 0.07). TCCdid not differ between the groups, although subjects with AD had higher concentrations than the other groups. In the combined sample of subjects with MCI, AD, and oDem, higher levels of C3a correlated with higher levels of TCC (r 1⁄4 0.51, p < 0.001), SAP (r 1⁄4 0.40, p< 0.001), and tau (r1⁄4 0.18, p1⁄4 0.048). Higher levels of C5a correlated with more impairment on memory, executive functioning, and the MMSE (r1⁄4 0.22-0.30, p 1⁄4 0.05-0.002). Higher levels of TCC correlated with higher SAP levels (r 1⁄4 0.41, p < 0.001) and more functional impairment (r 1⁄4 0.25, p 1⁄4 0.018).Conclusions: The innate immune system is actively involved in neurodegeneration and may provide diagnostic and prognostic information for AD. The large reduction of C3a in subjects with MCI, AD and oDem, suggests increased use of this factor, regardless of the cause of neurodegeneration. Alternatively, increased C3a levels may protect against neurodegeneration. The increase of C5a in AD suggests a disease specific activation of the lytic complement pathway. Since this measure correlated with clinical measures of severity, C5a activation may be a relatively late event in the disease process.