Richard Batrla

Hepatitis B virus surface antigen levels: A guide to sustained response to peginterferon alfa‐2a in HBeAg‐negative chronic hepatitis B

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 log10 IU/mL) and D (median, 3.85 log10 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 log10 IU/mL, respectively, P < 0.001), but not during treatment with lamivudine alone (−0.02 log10 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 log10 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. (HEPATOLOGY 2009;49:1141–1150.)

Hepatitis B surface antigen serum level is associated with fibrosis severity in treatment-naïve, e antigen-positive patients

BACKGROUND & AIMS Little is currently known about the association between serum HBsAg or HBV DNA levels and the severity of liver disease in chronic hepatitis B (CHB) patients. Therefore, we investigated these relationships in a large cohort of unselected, well-characterized, treatment-naïve CHB patients. METHODS CHB patients were assessed at the Hôpital Beaujon in Paris, France, between 2000 and 2008. Serum samples and liver biopsies were obtained on the same day. HBsAg, HBV DNA, and HBV genotype were investigated using commercial diagnostic assays and liver histology was scored using the METAVIR system. RESULTS 406 patients were included in this cross-sectional study. Serum HBsAg and HBV DNA levels in hepatitis B e antigen-positive (HBeAg[+]) patients showed strong correlation (r=0.44, p<0.0001), as did serum HBsAg levels and fibrosis severity (r=0.43, p<0.0001). HBeAg(+) patients with moderate to severe fibrosis exhibited significantly lower serum HBsAg and HBV DNA levels compared with patients with no or mild fibrosis. Modeling analysis suggested a serum HBsAg cut-off of 3.85 logIU/ml would provide a theoretical sensitivity of 100% (95% CI: 0-100), theoretical specificity of 86% (95% CI: 50-100), and a negative predictive value of 100% (95% CI: 67-100) in HBeAg(+) patients infected with HBV genotype B or C. CONCLUSIONS We found an association between low serum HBsAg levels and moderate to severe fibrosis in HBeAg(+) CHB patients. Furthermore, we described a serum HBsAg cut-off for the prediction of fibrosis severity in CHB patients infected with HBV genotype B or C.

Serum Levels of Hepatitis B Surface Antigen Predict Severity of Fibrosis in Patients With E Antigen-Positive Chronic Hepatitis B

BACKGROUND & AIMS Noninvasive techniques are needed to assess hepatic fibrosis in patients with chronic hepatitis B. We developed a scoring system to determine the degree of fibrosis in patients with genotype B or genotype C hepatitis B virus (HBV) infection and positive for the hepatitis B e antigen. METHODS We performed a retrospective study to identify baseline variables associated with the severity of fibrosis (METAVIR scores, F0-F4) in a large phase 3 clinical trial of predominantly Asian patients (n = 710), using multivariate logistic regression analyses. Significant variables were used to construct predictive models using optimal cut-off values. The final model was validated in similar patients from a large phase 4 clinical trial (n = 465). RESULTS We developed 2 prediction scoring systems (PSs). PS1 analyzed data on HBV genotype (B vs. C), patient age (<30 vs. ≥30 y), level of hepatitis B surface antigen (≤17,500 vs. >17,500 IU/mL), and level of alanine aminotransferase (≤3-fold vs. >3-fold the upper limit of normal). PS2 analyzed data on only age and level of hepatitis B surface antigen. PS1 identified patients with F0 to F1 vs. F2 to F4 fibrosis with more than 87% specificity and a positive predictive value greater than 75; it identified patients with F0 to F2 vs. F2 to F4 fibrosis with approximately 95% specificity and a positive predictive value (PPV) of approximately 97%. PS2 identified patients with F0 to F1 fibrosis with less accuracy than PS1, but identified patients with F0 to F2 fibrosis with an almost identical level of sensitivity and PPV. CONCLUSIONS We developed a simple scoring system to determine the severity of fibrosis in patients with genotypes B or C HBV infection who are hepatitis B e antigen positive. Our system differentiated patients with no or mild fibrosis (F0-F1) from those with marked or severe (F2-F4) fibrosis with a high PPV. The high level of specificity for the identification of nonsevere fibrosis (F0-F2) limits the risk of overlooking patients with severe fibrosis (F3-F4).

Personalized health care beyond oncology: new indications for immunoassay‐based companion diagnostics

Personalized health care (PHC) is an evolving field of medicine aimed at providing the right therapy to the right patient at the right time. This approach often incorporates the use of companion diagnostics (CDx) assays that provide information essential for the safe and effective use of the corresponding drug. In addition to oncology, many other therapy areas, such as cardiovascular, neurological, and infectious and inflammatory diseases, may benefit from PHC, owing to disease complexity and heterogeneity. Furthermore, although most U.S. Food and Drug Administration–approved CDx are based on molecular‐based technologies, immunoassays can provide a significant contribution to the evolution of CDx in patient management. In this review we discuss how the incorporation of biomarker immunoassays into routine diagnostic testing may allow early and definitive detection of Alzheimers disease and enable population enrichment in clinical trials. In addition, we will describe how biomarker‐based CDx immunoassays have potential utility for stratifying patients with asthma based on their potential response to therapy and for selecting treatment according to phenotypic profile. Continued research into the underlying disease pathology and development of accurate and reliable diagnostic assays may ensure that PHC becomes the future standard for many indications.

CSF biomarkers of Alzheimer's disease concord with amyloid-β PET and predict clinical progression: A study of fully automated immunoassays in BioFINDER and ADNI cohorts

We studied whether fully automated Elecsys cerebrospinal fluid (CSF) immunoassay results were concordant with positron emission tomography (PET) and predicted clinical progression, even with cutoffs established in an independent cohort.

A user's guide for α-synuclein biomarker studies in biological fluids: Perianalytical considerations

Parkinsons disease biomarkers are needed to increase diagnostic accuracy, to objectively monitor disease progression and to assess therapeutic efficacy as well as target engagement when evaluating novel drug and therapeutic strategies. This article summarizes perianalytical considerations for biomarker studies (based on immunoassays) in Parkinsons disease, with emphasis on quantifying total α‐synuclein protein in biological fluids. Current knowledge and pitfalls are discussed, and selected perianalytical variables are presented systematically, including different temperature of sample collection and types of collection tubes, gradient sampling, the addition of detergent, aliquot volume, the freezing time, and the different thawing methods. We also discuss analytical confounders. We identify gaps in the knowledge and delineate specific areas that require further investigation, such as the need to identify posttranslational modifications of α‐synuclein and antibody‐independent reference methods for quantification, as well as the analysis of potential confounders, such as comorbidities, medication, and phenotypes of Parkinsons disease in larger cohorts. This review could be used as a guideline for future Parkinsons disease biomarker studies and will require regular updating as more information arises in this growing field, including new technical developments as they become available. In addition to reviewing best practices, we also identify the current technical limitations and gaps in the knowledge that should be addressed to enable accurate and quantitative assessment of α‐synuclein levels in the clinical setting.

Ultra-deep sequencing reveals high prevalence and broad structural diversity of hepatitis B surface antigen mutations in a global population

The diversity of the hepatitis B surface antigen (HBsAg) has a significant impact on the performance of diagnostic screening tests and the clinical outcome of hepatitis B infection. Neutralizing or diagnostic antibodies against the HBsAg are directed towards its highly conserved major hydrophilic region (MHR), in particular towards its “a” determinant subdomain. Here, we explored, on a global scale, the genetic diversity of the HBsAg MHR in a large, multi-ethnic cohort of randomly selected subjects with HBV infection from four continents. A total of 1553 HBsAg positive blood samples of subjects originating from 20 different countries across Africa, America, Asia and central Europe were characterized for amino acid variation in the MHR. Using highly sensitive ultra-deep sequencing, we found 72.8% of the successfully sequenced subjects (n = 1391) demonstrated amino acid sequence variation in the HBsAg MHR. This indicates that the global variation frequency in the HBsAg MHR is threefold higher than previously reported. The majority of the amino acid mutations were found in the HBV genotypes B (28.9%) and C (25.4%). Collectively, we identified 345 distinct amino acid mutations in the MHR. Among these, we report 62 previously unknown mutations, which extends the worldwide pool of currently known HBsAg MHR mutations by 22%. Importantly, topological analysis identified the “a” determinant upstream flanking region as the structurally most diverse subdomain of the HBsAg MHR. The highest prevalence of “a” determinant region mutations was observed in subjects from Asia, followed by the African, American and European cohorts, respectively. Finally, we found that more than half (59.3%) of all HBV subjects investigated carried multiple MHR mutations. Together, this worldwide ultra-deep sequencing based genotyping study reveals that the global prevalence and structural complexity of variation in the hepatitis B surface antigen have, to date, been significantly underappreciated.

Blood-based biomarkers for Alzheimer disease: mapping the road to the clinic

Biomarker discovery and development for clinical research, diagnostics and therapy monitoring in clinical trials have advanced rapidly in key areas of medicine — most notably, oncology and cardiovascular diseases — allowing rapid early detection and supporting the evolution of biomarker-guided, precision-medicine-based targeted therapies. In Alzheimer disease (AD), breakthroughs in biomarker identification and validation include cerebrospinal fluid and PET markers of amyloid-β and tau proteins, which are highly accurate in detecting the presence of AD-associated pathophysiological and neuropathological changes. However, the high cost, insufficient accessibility and/or invasiveness of these assays limit their use as viable first-line tools for detecting patterns of pathophysiology. Therefore, a multistage, 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 Review summarizes the efforts of an international 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 pathway from identification and assay development to validation for clinical use.Advances in biomarker research are aiding the development of targeted therapies and prevention strategies for Alzheimer disease (AD). In this Review, an international working group assesses the current status of blood-based AD biomarkers and outlines a roadmap for future research.Key pointsCerebrospinal fluid (CSF) and PET markers of amyloid-β and tau proteins are accurate in detecting the neuropathological changes of Alzheimer disease (AD).The use of CSF and PET biomarkers is limited by invasiveness or high costs; to address these issues, blood-based AD biomarkers are eagerly awaited.An international, interdisciplinary expert working group was convened by the Alzheimer’s Precision Medicine Initiative to discuss the ideal development process for blood-based biomarkers.Nineteen blood-based biomarker assays were selected by the working group for further consideration.The working group outlined the pathway from biomarker identification and assay development to validation for clinical use and proposed clear steps for effective academic–industry co-development of blood-based AD biomarkers.The development, standardization and validation of blood-based biomarkers will be paramount to the implementation of precision medicine in AD.

Detection of in vivo hepatitis B virus surface antigen mutations-A comparison of four routine screening assays

An important requirement for a state‐of‐the‐art hepatitis B surface antigen (HBsAg) screening assay is reliable detection of mutated HBsAg. Currently, there is a striking shortage of data regarding the detection rates of in vivo HBsAg mutations for these clinically important assays. Therefore, we compared the detection rates of four commercial HBsAg screening assays using a global cohort of 1553 patients from four continents with known HBV genotypes. These samples, which represent the broadest spectrum of known and novel HBsAg major hydrophilic region (MHR) mutations to date, were analyzed for the presence of HBsAg using the Roche Elecsys® HBsAg II Qualitative, Siemens ADVIA Centaur XP HBsAg II, Abbott Architect HBsAg Qualitative II and DiaSorin Liaison® HBsAg Qualitative assays, respectively. Of the 1553 samples, 1391 samples could be sequenced; of these, 1013 (72.8%) carried at least one of the 345 currently known amino acid substitutions (distinct HBsAg mutation) in the HBsAg MHR. All 1553 patient samples were positive for HBsAg using the Elecsys® HBsAg II Qual assay, with a sensitivity (95% confidence interval) of 99.94% (99.64%‐100%), followed by the Abbott Architect 99.81% (99.44%‐99.96%), Siemens ADVIA 99.81% (99.44%‐99.96%) and DiaSorin Liaison® 99.36% (98.82%‐99.69%) assays, respectively. Our results indicate that the Elecsys® HBsAg II Qual assay exhibits the highest sensitivity among the commercial HBsAg screening assays, and demonstrate that its capacity to detect HBV infection is not compromised by HBsAg MHR mutants.

The impact of preanalytical variables on measuring cerebrospinal fluid biomarkers for Alzheimer's disease diagnosis: A review

Cerebrospinal fluid (CSF) biomarkers have the potential to improve the diagnostic accuracy of Alzheimers disease, yet there is a lack of harmonized preanalytical CSF handling protocols.