- Email: [email protected]
Standardization of a method for diagnostic biomarker validation for neurodegenerative diseases: App assays as example
Poster Presentations: P1
acceptable range in 144 out of 146 runs. Average values for each reagent lot are within 10% of the training set mean values. The plot shows longitudinal performance of amyloid-b results for the 2 pools. Conclusions: Using our protocol we were able to maintain acceptable performance of Ab1-42 throughout 17 months and 4 different lots of reagents. References: LM Shaw, H. Vanderstichele, M. Knapik-Czajka, et al. Acta Neuropathol. 2011 May;121(5):597-609.
P1-120
STANDARDIZATION OF A METHOD FOR DIAGNOSTIC BIOMARKER VALIDATION FOR NEURODEGENERATIVE DISEASES: APP ASSAYS AS EXAMPLE
Linda Josephine Christine van Waalwijk van Doorn1, Marleen J. KoelSimmelink2, Ute Hausmann3, Hans Klafki3,4, Hanne Struyfs5, Philipp Linning6, Hans-Joachim Knoelker6, Harry Twaalfhoven2, H. Bea Kuiperij1, Eugeen Vanmechelen7, Marcel Verbeek1, Sebastiaan Engelborghs8, Jens Wiltfang4, Charlotte E. Teunissen2, 1 Radboud University Medical Center, Radboud Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands; 2VU University Medical Center, Alzheimer Center VUmc, Neurocampus, Amsterdam, Netherlands; 3LVR-Hospital Essen, University of Duisburg-Essen, Essen, Germany; 4University Medical Center Goettingen, Georg-August-University, Goettingen, Germany; 5University of Antwerp, Antwerp, Belgium; 6Technische Universitat Dresden, Dresden, Germany; 7 ADx NeuroSciences, Ghent, Belgium; 8Institute Born-Bunge, University of Antwerp, Antwerp, Belgium. Contact e-mail: Linda. [email protected] Background: Biomarker assays need to be thoroughly analytically validated before they can be implemented in clinical practice. For this purpose, the BIOMARKAPD consortium developed two standard operation procedures (SOPs) for evaluation of biomarker assays based on international guidelines. The aim of the present study was to analytically validate the performance of two different assays detecting soluble Ab precursor protein (sAPP) in CSF using these SOPs. Methods: Two different biomarker assays for the quantification of sAPPa and sAPPb concentrations were validated in three different laboratories: the duplex immunoassay kit from MSD and the sAPPa and b ELISA kit from IBL-international. The tested performance parameters included precision, sensitivity, dilutional linearity, recovery, parallelism. Both inter-assay and inter-laboratory variation for n¼60 clinical samples were analyzed. Results: Performance parameters of the MSD and IBL assays were similar in two laboratories when performed according to the SOPs. In this, precision evaluation revealed intra-assay variations <5% and inter-assay variations <11%. Sensitivity showed limit of detections of less than 3ng/mL. Dilutional lineary did not show any hook effect. All assays demonstrated a good recovery (85-110%) for one laboratory, but only for the IBL sAPPa in the other laboratory. Parallelism results from one laboratory showed that the measured concentrations in clinical samples was directly comparable with the calibrator concentration (97%). Inter-assay variation showed a good correlation between two out of three laboratories for the quantification of both assays (MSD: r2 ¼ 0.950.97, IBL: r2 ¼ 0.94-0.96). With regards to the inter-laboratory variation for sAPPa two out of three laboratories showed a good inter-laboratory correlation for the MSD assay (r2 ¼ 0.70) and IBL assay (r2 ¼ 0.92). For sAPPb similar results were found (MSD: r2 ¼ 0.80, IBL: r2¼ 0.94). Based on these experiences, the SOP is further optimized and a standard data analysis template is devel-
P387
oped. Conclusions: Both MSD and IBL assays are of sufficient quality and perform well when applied properly. Multicenter evaluation of our SOPs show that these are convenient and useful tools for the validation of new biomarker assays.
P1-121
COMPARISON OF DIFFERENT ß-AMYLOID ISOFORMS IN CSF TO DETECT AMYLOID PATHOLOGY IN COGNITIVELY NORMAL SUBJECTS AND PATIENTS WITH DEMENTIA
Alberto Lleo1, Erik Stoops2, Daniel Andres Alcolea1, Leentje Demeyer2, Kimberley Mauroo2, Victor Herbst3, Valle Camacho4, Estrella Morenas4, Jordi Clarimon4, Marıa Carmona4, Rafael Blesa4, Juan Fortea4, Hugo Vanderstichele2, 1Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; 2ADx NeuroSciences, Gent, Belgium; 3EUROIMMUN, L€ubeck, Germany; 4Hospital de Sant Pau, Barcelona, Spain. Contact e-mail: Hugo. [email protected] Background: CSF biomarkers are used to support the diagnosis of
Alzheimer’s disease. The extensive implementation of CSF biomarkers in clinical routine has been hampered by a lack standardization of test procedures and performance issues (precision, parallelism, interlab accuracy). Hence, there is an urgent need for approved immunoassays with high diagnostic performance for use in routine laboratories or inclusion into clinical trials. Methods: We evaluated the performance of a novel series of ELISAs (EUROIMMUN) for Ab isoforms (Ab1-42, Ab1-40, AbN-42, Ab1-38) and total tau compared to currently used assays. The diagnostic accuracy was determined for single or combination of Ab peptides and the correlation with imaging findings (PIB or Florbetapir) was established. All assays were harmonized with respect to test procedures and components. We tested CSF samples from cognitively normal controls (n¼50) and patients with AD dementia (n¼50), amnestic mild cognitive impairment (MCI, n¼50) and dementia with Lewy bodies (n¼32) using one kit lot. We analyzed the correlation of Aß peptide concentrations in CSF with presence or absence of amyloid pathology in imaging tests (PIB or Florbetapir PET; n¼60). Results: The novel assays showed a good performance to differentiate between patient groups. Discrimination of patient groups, as well as correlation with imaging was higher using the ratios Ab1-42/Ab1-40, Ab1-42/Ab1-38 or Ab1-42/tau compared to any single analyte. No CSF dilution was required in the assay to quantify Ab1-38. Analysis of Ab1-42 or AbN-42 revealed no major differences to discriminate between patient groups. Conclusions: The diagnostic performance of the EUROIMMUN assays for Ab1-42 and tau proteins to identify subjects with AD was confirmed. The ratios Ab1-42/Ab1-40, Ab1-42/Ab1-38 or Ab142/tau outperformed the single peptides to discriminate AD dementia patients from controls. The correlation with imaging was higher when using the ratio Ab1-42/Ab1-40 than with single Ab peptides.
P1-122
A 24-WEEK, RANDOMIZED, CONTROLLED TRIAL OF 13.3 MG/24 H VERSUS 4.6 MG/24 H RIVASTIGMINE PATCH IN PATIENTS WITH SEVERE ALZHEIMER’S DISEASE: ANALYSIS OF NEUROPSYCHIATRIC INVENTORY ITEMS
George Grossberg1, Xiangyi Meng2, Drew Velting2, 1St. Louis University School of Medicine, St. Louis, MO, USA; 2Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA. Contact e-mail: [email protected]
acceptable range in 144 out of 146 runs. Average values for each reagent lot are within 10% of the training set mean values. The plot shows longitudinal performance of amyloid-b results for the 2 pools. Conclusions: Using our protocol we were able to maintain acceptable performance of Ab1-42 throughout 17 months and 4 different lots of reagents. References: LM Shaw, H. Vanderstichele, M. Knapik-Czajka, et al. Acta Neuropathol. 2011 May;121(5):597-609.
P1-120
STANDARDIZATION OF A METHOD FOR DIAGNOSTIC BIOMARKER VALIDATION FOR NEURODEGENERATIVE DISEASES: APP ASSAYS AS EXAMPLE
Linda Josephine Christine van Waalwijk van Doorn1, Marleen J. KoelSimmelink2, Ute Hausmann3, Hans Klafki3,4, Hanne Struyfs5, Philipp Linning6, Hans-Joachim Knoelker6, Harry Twaalfhoven2, H. Bea Kuiperij1, Eugeen Vanmechelen7, Marcel Verbeek1, Sebastiaan Engelborghs8, Jens Wiltfang4, Charlotte E. Teunissen2, 1 Radboud University Medical Center, Radboud Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands; 2VU University Medical Center, Alzheimer Center VUmc, Neurocampus, Amsterdam, Netherlands; 3LVR-Hospital Essen, University of Duisburg-Essen, Essen, Germany; 4University Medical Center Goettingen, Georg-August-University, Goettingen, Germany; 5University of Antwerp, Antwerp, Belgium; 6Technische Universitat Dresden, Dresden, Germany; 7 ADx NeuroSciences, Ghent, Belgium; 8Institute Born-Bunge, University of Antwerp, Antwerp, Belgium. Contact e-mail: Linda. [email protected] Background: Biomarker assays need to be thoroughly analytically validated before they can be implemented in clinical practice. For this purpose, the BIOMARKAPD consortium developed two standard operation procedures (SOPs) for evaluation of biomarker assays based on international guidelines. The aim of the present study was to analytically validate the performance of two different assays detecting soluble Ab precursor protein (sAPP) in CSF using these SOPs. Methods: Two different biomarker assays for the quantification of sAPPa and sAPPb concentrations were validated in three different laboratories: the duplex immunoassay kit from MSD and the sAPPa and b ELISA kit from IBL-international. The tested performance parameters included precision, sensitivity, dilutional linearity, recovery, parallelism. Both inter-assay and inter-laboratory variation for n¼60 clinical samples were analyzed. Results: Performance parameters of the MSD and IBL assays were similar in two laboratories when performed according to the SOPs. In this, precision evaluation revealed intra-assay variations <5% and inter-assay variations <11%. Sensitivity showed limit of detections of less than 3ng/mL. Dilutional lineary did not show any hook effect. All assays demonstrated a good recovery (85-110%) for one laboratory, but only for the IBL sAPPa in the other laboratory. Parallelism results from one laboratory showed that the measured concentrations in clinical samples was directly comparable with the calibrator concentration (97%). Inter-assay variation showed a good correlation between two out of three laboratories for the quantification of both assays (MSD: r2 ¼ 0.950.97, IBL: r2 ¼ 0.94-0.96). With regards to the inter-laboratory variation for sAPPa two out of three laboratories showed a good inter-laboratory correlation for the MSD assay (r2 ¼ 0.70) and IBL assay (r2 ¼ 0.92). For sAPPb similar results were found (MSD: r2 ¼ 0.80, IBL: r2¼ 0.94). Based on these experiences, the SOP is further optimized and a standard data analysis template is devel-
P387
oped. Conclusions: Both MSD and IBL assays are of sufficient quality and perform well when applied properly. Multicenter evaluation of our SOPs show that these are convenient and useful tools for the validation of new biomarker assays.
P1-121
COMPARISON OF DIFFERENT ß-AMYLOID ISOFORMS IN CSF TO DETECT AMYLOID PATHOLOGY IN COGNITIVELY NORMAL SUBJECTS AND PATIENTS WITH DEMENTIA
Alberto Lleo1, Erik Stoops2, Daniel Andres Alcolea1, Leentje Demeyer2, Kimberley Mauroo2, Victor Herbst3, Valle Camacho4, Estrella Morenas4, Jordi Clarimon4, Marıa Carmona4, Rafael Blesa4, Juan Fortea4, Hugo Vanderstichele2, 1Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; 2ADx NeuroSciences, Gent, Belgium; 3EUROIMMUN, L€ubeck, Germany; 4Hospital de Sant Pau, Barcelona, Spain. Contact e-mail: Hugo. [email protected] Background: CSF biomarkers are used to support the diagnosis of
Alzheimer’s disease. The extensive implementation of CSF biomarkers in clinical routine has been hampered by a lack standardization of test procedures and performance issues (precision, parallelism, interlab accuracy). Hence, there is an urgent need for approved immunoassays with high diagnostic performance for use in routine laboratories or inclusion into clinical trials. Methods: We evaluated the performance of a novel series of ELISAs (EUROIMMUN) for Ab isoforms (Ab1-42, Ab1-40, AbN-42, Ab1-38) and total tau compared to currently used assays. The diagnostic accuracy was determined for single or combination of Ab peptides and the correlation with imaging findings (PIB or Florbetapir) was established. All assays were harmonized with respect to test procedures and components. We tested CSF samples from cognitively normal controls (n¼50) and patients with AD dementia (n¼50), amnestic mild cognitive impairment (MCI, n¼50) and dementia with Lewy bodies (n¼32) using one kit lot. We analyzed the correlation of Aß peptide concentrations in CSF with presence or absence of amyloid pathology in imaging tests (PIB or Florbetapir PET; n¼60). Results: The novel assays showed a good performance to differentiate between patient groups. Discrimination of patient groups, as well as correlation with imaging was higher using the ratios Ab1-42/Ab1-40, Ab1-42/Ab1-38 or Ab1-42/tau compared to any single analyte. No CSF dilution was required in the assay to quantify Ab1-38. Analysis of Ab1-42 or AbN-42 revealed no major differences to discriminate between patient groups. Conclusions: The diagnostic performance of the EUROIMMUN assays for Ab1-42 and tau proteins to identify subjects with AD was confirmed. The ratios Ab1-42/Ab1-40, Ab1-42/Ab1-38 or Ab142/tau outperformed the single peptides to discriminate AD dementia patients from controls. The correlation with imaging was higher when using the ratio Ab1-42/Ab1-40 than with single Ab peptides.
P1-122
A 24-WEEK, RANDOMIZED, CONTROLLED TRIAL OF 13.3 MG/24 H VERSUS 4.6 MG/24 H RIVASTIGMINE PATCH IN PATIENTS WITH SEVERE ALZHEIMER’S DISEASE: ANALYSIS OF NEUROPSYCHIATRIC INVENTORY ITEMS
George Grossberg1, Xiangyi Meng2, Drew Velting2, 1St. Louis University School of Medicine, St. Louis, MO, USA; 2Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA. Contact e-mail: [email protected]