Elecsys CSF biomarker assays may provide reliable alternatives to PET in Alzheimer's disease diagnosis.

Biomarker discovery and development for clinical research, diagnostics and therapy monitoring in clinical trials have advanced rapidly in key areas of medicine, notably oncology and cardiovascular diseases, allowing for rapid early detection and supporting the evolution of biomarker-guided precision medicine-based targeted therapies. In Alzheimer’s disease (AD), breakthroughs in biomarker identification and validation include the cerebrospinal fluid (CSF) and positron emission tomography (PET) markers of amyloid β (Aβ) and tau proteins, which are highly accurate in detecting the presence of pathophysiological and neuropathological changes of AD. However, their high cost, insufficient accessibility, or invasiveness may limit their use as viable first-line tools for detecting patterns of pathophysiology. Therefore, a multi-stage, tiered approach is needed, prioritizing development of an initial screen to exclude from these tests the high numbers of people with cognitive deficits who do not demonstrate evidence of underlying AD pathophysiology. This perspective summarizes the efforts of a working group that aimed to survey the current landscape of blood-based AD biomarkers, and outlines operational steps for an effective academic-industry co-development and path forward from identification and assay development to validation for clinical use.

We investigated the relationship between hepatitis B virus surface antigen (HBsAg) serum level decline and posttreatment response in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B from a large multinational study of pegylated interferon alfa-2a (peginterferon alfa-2a), with or without lamivudine, versus lamivudine alone. Serum HBsAg was quantified using the Architect assay (Abbott Diagnostics) at pretreatment, end of treatment (week 48), and 6 months after the end of treatment (week 72) in sera from 386 of the 537 patients who participated in the multinational study (peginterferon alfa-2a, 127; peginterferon alfa-2a plus lamivudine, 137; lamivudine monotherapy, 122). Pretreatment HBsAg levels varied according to genotype, with the highest levels present in patients infected with genotypes A (median, 4.11 log 10 IU/mL) and D (median, 3.85 log 10 IU/mL). Significant on-treatment decline in HBsAg was observed during treatment with peginterferon alfa-2a (alone or combined with lamivudine; mean decline at week 48, ؊0.71 and ؊0.67 log 10 IU/mL, respectively, P < 0.001), but not during treatment with lamivudine alone (؊0.02 log 10 IU/mL). Significantly more patients treated with peginterferon alfa-2a (21%) or peginterferon alfa-2a plus lamivudine (17%) achieved HBsAg levels <100 IU/mL at the end of treatment compared with lamivudine (1%) (both P < 0.001 versus lamivudine). End-of-treatment HBsAg level correlated strongly with HBV DNA suppression to <400 copies/mL 6 months posttreatment. An HBsAg level <10 IU/mL at week 48 and on-treatment decline >1 log 10 IU/mL were significantly associated with sustained HBsAg clearance 3 years after treatment (both P < 0.0001). Conclusion: On-treatment quantification of HBsAg in patients with HBeAg-negative chronic hepatitis B treated with peginterferon alfa-2a may help identify those likely to be cured by this therapy and optimize treatment strategies. C hronic hepatitis B is a global health problem accounting for 1 million deaths each year. 1 Ageadjusted death rates are 3 to 3.6 times higher in carriers of hepatitis B virus (HBV) surface antigen (HBsAg) than in persons without HBV infection. 2 The aim of treatment for patients with chronic hepatitis B (CHB) is to decrease progression of liver disease to cirrhosis and hepatocellular carcinoma, with the ultimate aim of improving survival. This can be pursued by maintaining constant inhibition of viral replication through a longterm treatment with nucleos(t)ide analogs or by inducing, through the combined antiviral and immunomodulatory Abbreviations: ALT, alanine aminotransferase; CART, classification and regression tree; CHB, chronic hepatitis B; HBeAg, hepatitis B e antigen; HBsAg, hepatitis B virus surface antigen; HBV, hepatitis B virus;

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with a complex and heterogeneous pathophysiology. The number of people living with AD is predicted to increase; however, there are no disease-modifying therapies currently available and none have been successful in late-stage clinical trials. Fluid biomarkers measured in cerebrospinal fluid (CSF) or blood hold promise for enabling more effective drug development and establishing a more personalized medicine approach for AD diagnosis and treatment. Biomarkers used in drug development programmes should be qualified for a specific context of use (COU). These COUs include, but are not limited to, subject/patient selection, assessment of disease state and/or prognosis, assessment of mechanism of action, dose optimization, drug response monitoring, efficacy maximization, and toxicity/adverse reactions identification and minimization. The core AD CSF biomarkers Aβ42, t-tau, and p-tau are recognized by research guidelines for their diagnostic utility and are being considered for qualification for subject selection in clinical trials. However, there is a need to better understand their potential for other COUs, as well as identify additional fluid biomarkers reflecting other aspects of AD pathophysiology. Several novel fluid biomarkers have been proposed, but their role in AD pathology and their use as AD biomarkers have yet to be validated. In this review, we summarize some of the pathological mechanisms implicated in the sporadic AD and highlight the data for several established and novel fluid biomarkers (including BACE1, TREM2, YKL-40, IP-10, neurogranin, SNAP-25, synaptotagmin, α-synuclein, TDP-43, ferritin, VILIP-1, and NF-L) associated with each mechanism. We discuss the potential COUs for each biomarker.

Introduction This study examines the utility of a multipanel of cerebrospinal fluid (CSF) biomarkers complementing Alzheimer's disease (AD) biomarkers in a clinical research sample. We compared biomarkers across groups defined by clinical diagnosis and pTau181/Aβ42 status (+/−) and explored their value in predicting cognition. Methods CSF biomarkers amyloid beta (Aβ)42, pTau181, tTau, Aβ40, neurogranin, neurofilament light (NfL), α‐synuclein, glial fibrillary acidic protein (GFAP), chitinase‐3‐like protein 1 (YKL‐40), soluble triggering receptor expressed on myeloid cells 2 (sTREM2), S100 calcium binding protein B (S100B), and interleukin 6 (IL6), were measured with the NeuroToolKit (NTK) for 720 adults ages 40 to 93 years (mean age = 63.9 years, standard deviation [SD] = 9.0; 50 with dementia; 54 with mild cognitive impairment [MCI], 616 unimpaired). Results Neurodegeneration and glial activation biomarkers were elevated in pTau181/Aβ42+ MCI/dementia participants relative to all pTau181/Aβ42‐ participants. Neurodegeneration biomarkers increased with clinical severity among pTau181/Aβ42+ participants and predicted worse cognitive performance. Glial activation biomarkers were unrelated to cognitive performance. Discussion The NTK contains promising markers that improve the pathophysiological characterization of AD. Neurodegeneration biomarkers beyond tTau improved statistical prediction of cognition and disease stages.