Christina Rabe

Technical performance of a novel, fully automated electrochemiluminescence immunoassay for the quantitation of β-amyloid (1-42) in human cerebrospinal fluid.

Available assays for quantitation of the Alzheimers disease (AD) biomarker amyloid‐beta 1–42 (Aβ [1–42]) in cerebrospinal fluid demonstrate significant variability and lack of standardization to reference measurement procedures (RMPs). We report analytical performance data for the novel Elecsys β‐amyloid (1–42) assay (Roche Diagnostics).

IL-6 pathway-driven investigation of response to IL-6 receptor inhibition in rheumatoid arthritis

Objectives To determine whether heterogeneity in interleukin-6 (IL-6), IL-6 receptor and other components of the IL-6 signalling pathway/network, at the gene, transcript and protein levels, correlate with disease activity in patients with rheumatoid arthritis (RA) and with clinical response to tocilizumab. Design Biomarker samples and clinical data for five phase 3 trials of tocilizumab were analysed using serum (3751 samples), genotype (927 samples) and transcript (217 samples) analyses. Linear regression was then used to assess the association between these markers and either baseline disease activity or treatment response. Results Higher baseline serum IL-6 levels were significantly associated (p<0.0001) with higher baseline DAS28, erythrocyte sedimentation rate, C reactive protein and Health Assessment Questionnaire in patients whose responses to disease-modifying antirheumatic drugs (DMARD-IR) and to antitumour necrosis factor (aTNF-IR) were inadequate and patients who were naive/responders to methotrexate (MTX). Higher baseline serum IL-6 levels were also significantly associated with better clinical response to tocilizumab (versus placebo) measured by cDAS28 in the pooled DMARD-IR (p<0.0001) and MTX-naive populations (p=0.04). However, the association with treatment response was weak. A threefold difference in baseline IL-6 level corresponded to only a 0.17-unit difference in DAS28 at week 16. IL-6 pathway single nucleotide polymorphisms and RNA levels also were not strongly associated with treatment response. Conclusions Our analyses illustrate that the biological activity of a disease-associated molecular pathway may impact the benefit of a therapy targeting that pathway. However, the variation in pathway activity, as measured in blood, may not be a strong predictor. These data suggest that the major contribution to variability in clinical responsiveness to therapeutics in RA remains unknown.

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.

Biomarker data from scarlet road: A global phase 3 study of gantenerumab in patients with prodromal Alzheimer's disease

Bruno Vellas, Isabelle Carrie, Sophie Guyonnet, Jacques Touchon, Thierry Dantoine, Jean-François Dartigues, Marie Noelle Cufi, Serge Bordes, Yves Gasnier, Philippe Robert, Lawrence Bories, Olivier Rouaud, Francoise Desclaux, Kristel Sudres, Marc Bonnefoy, Alain Pesce, Bertrand Fougere, Julien Delrieu, Catherine Faisant, Françoise Lala, Charlotte Dupuy, Christelle Cantet, Nicola Coley, Sylvie Belleville, Sherry L. Willis, Michael W. Weiner, Pierre Jean Ousset, Sandrine Andrieu, INSERM UMR 1027, Toulouse, France; University of Toulouse III, Toulouse, France; CHU Toulouse, Toulouse, France; CHU Toulouse, Toulouse, France; INSERM UMR 1027, Toulouse, France; CHU Montpellier, Montpellier, France; CHU Limoges, Limoges, France; INSERM U897, Bordeaux, France; Bordeaux University, Bordeaux, France; Memory consultation, CHU Bordeaux, Bordeaux, France; Bordeaux University Hospital, Bordeaux, France; CH Castres, Castres, France; CH Tarbes, Tarbes, France; CHU Nice, Nice, France; CH Foix, Foix, France; Hôpital General, Dijon, France; CH Lavaur, Lavaur, France; CH Montauban, Montauban, France; CHU Lyon SUD, Lyon, France; CH Princesse Grace, Monaco, Monaco; Institute of Aging, University Hospital Toulouse, Toulouse, France; Institut Universitaire de G eriatrie de Montr eal, Montr eal, QC, Canada; Universit e de Montr eal, Montr eal, QC, Canada; Indiana University, Indianapolis, IN, USA; University of California San Francisco, San Francisco, CA, USA; INSERM UMR 1027, Paul Sabatier University, Toulouse, France. Contact e-mail: vellas. b@chu-toulouse.fr

METHOD COMPARISON OF AB(1-42) MEASURED IN HUMAN CEREBROSPINAL FLUID SAMPLES BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY, THE INNO-BIA ALZBIO3 ASSAY, AND THE ELECSYS® B-AMYLOID(1-42) ASSAY

INHUMANCEREBROSPINALFLUID SAMPLESBY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY, THE INNO-BIA ALZBIO3 ASSAY, AND THE ELECSYS B-AMYLOID(1-42) ASSAY LeslieM. Shaw, Leona Fields, Magdalena Korecka, TeresaWalig orska, John Q. Trojanowski, Deirdre Allegranza, Tobias Bittner, Ying He, Kelly Morgan, Christina Rabe, University of Pennsylvania Hospital, Philadelphia, PA, USA; 2 Roche Diagnostics International AG, Rotkreuz, Switzerland; 3 Roche Diagnostics GmbH, Penzberg, Germany; 4 Roche Diagnostics Corporation, Indianapolis, IN, USA. Contact e-mail: Les. Shaw@uphs.upenn.edu

Myeloid cell biology and inhibition of anti-tumor immune responses by MPDL3280A in urothelial bladder cancer

Treatment options for metastatic urothelial bladder cancer (UBC) are limited. Mutational complexity is known to be high in UBC and may correlate with increased immunogenicity. MPDL3280A, a human PD-L1 monoclonal antibody containing an engineered Fc-domain designed to promote a Th1-driven response, has demonstrated a RECIST response rate of 43% in diagnostically selected, pretreated patients with UBC. A total of 68 patients (67 with efficacy evaluable) were enrolled in the UBC cohort of the Phase I study; 45% were PD-L1 IHC diagnostic positive as defined by expression of PD-L1 on ≥ 5% of tumor-infiltrating immune cells. In the prescreened UBC population, the prevalence of PD-L1-positive patients was 27%. Comprehensive gene expression analyses of UBC tumors were conducted to interrogate the tumor immune microenvironment in PD-L1-positive tumors and to identify potential mechanisms associated with response or resistance to MPDL3280A. In this study, PD-L1-positive tumors exhibited a high prevalence of gene expression markers associated with T-effector cells (Teff), including perforin, IFNγ, CD8A, granzyme B, granzyme A and EOMES. Additionally, a low baseline signature of genes associated with myeloid cell markers, including IL1B and IL8, appeared to be statistically significantly associated (P<0.01) with MPDL3280A response, suggesting a potential role for myeloid biology in resistance to MPDL3280A treatment in UBC. Tumor burden markers, including CA-125, CA19-9 and human chorionic gonadotropin (HCG), have been associated with chemotherapy response markers in UBC. A marked decrease in these markers, including CEA, CA19-9, CA-125 and HCG, was observed with MPDL3280A response after 1 treatment cycle, potentially enabling an on-treatment monitoring alternative for response to therapy. Similarly, evaluation of cytokines on treatment identified markers, including IL-6 and IL-10, elevated as early as Cycle 2 only in patients without response to MPDL3280A. These circulating cytokines and tumor-associated gene signatures suggest potential mechanisms associated with resistance and response to MPDL3280A in UBC and provide a rationale for informed combination strategies to further improve treatment benefit in this indication.

BASELINE RECOVERY AND LONGITUDINAL STABILITY OF CEREBROSPINAL FLUID AMYLOID-β PEPTIDES: AN EVALUATION OF COLLECTION METHODS, LONGITUDINAL ASSAY PERFORMANCE, AND BIOMARKER STABILITY OVER A 2-YEAR PERIOD

was shown to be < 0.5 pg/mL and the LoQ < 5 pg/mL. No high dose hook effect was observed for samples containing up to 30000 pg/mL of phospho-Tau181. Linearity was shown across the clinical relevant range. A method comparison study with the INNOTEST PHOSPHO-TAU-(181P) assay demonstrated a good correlation (r>0.90). Conclusions:Automation, the mono test cartridge principle, short throughput times, and instrument flexibility are key attributes of the LUMIPULSE G instrument series making it the ideal platform to fulfill today’s needs for rapid and accurate quantification of CSF biomarkers. The novel Lumipulse G pTau 181 assay (under development) shows good sensitivity and precision, correlates well with the INNOTEST assay and completes the routine CSF biomarker panel for AD on LUMIPULSE.

Abstract PR03: CD8+ T-cell distribution and immunomodulator expression in BRAF-mutant melanoma affect the response to BRAF inhibitor and chemotherapy

Although intense effort has been made in studying immune cell dynamics in tumors after treatment with targeted therapies and to recharacterize tumor stages based on their immune cell components, less is known about how baseline immune cell characteristics in tumors affect response to approved therapies. Here we describe baseline expression of immune regulators and CD8+ T-cell distribution in BRAF-mutated metastatic melanoma and their relationship with progression-free survival (PFS) on vemurafenib and chemotherapy. To our knowledge, we are the first to describe the baseline characteristics of tumor-infiltrating lymphocytes and their impact on outcomes in a large randomized, controlled trial in melanoma. Archival or baseline samples were collected from patients in 2 clinical trials (BRIM2 and BRIM3) and analyzed. A total of 252 RNA samples were prepared from formalin-fixed, paraffin-embedded (FFPE) tissue samples and profiled for expression using a panel of 96 immune genes on the Fluidigm platform (Fluidigm Corp). Additionally, for 277 patients from the BRIM3 trial, CD8+ T cells were detected by immunohistochemistry (IHC) and quantified using Definiens (Definiens AG). Patients were defined as high or low expressers based on a median cutoff, and hazard ratios (HRs) were determined by cox proportional hazards modeling of PFS. HRs refer to the comparison of high and low expressing groups, where an HR A discovery (BRIM2) – validation (BRIM3) scheme was applied to assess the prognostic value of the expression of immune-related genes. Samples from the BRIM3 dacarbazine and vemurafenib arms were compared to assess the predictive value of the markers on the treatment effect of vemurafenib. Of the genes tested, 26 met our discovery criteria in the BRIM2 trial and 2, IL7 and IL12A, were validated in BRIM3. In the vemurafenib arm of BRIM3, patients with high expression of IL7 had improved PFS compared with patients with low IL7, with an HR of 0.63 (95% confidence interval [CI]: 0.41-0.97; P=0.03); high expression of IL12A had an HR of 0.58 (0.38-0.88; P=0.01). Neither gene was associated with PFS in the dacarbazine-treated arm; however, high and low expressers of both genes benefited from vemurafenib treatment. Because immune contexture is known to be associated with outcomes, slides were stained for CD8+ T-cell content in 3 marker areas: center, peripheral, and invasive margin. In the dacarbazine arm, increased PFS was seen in patients with higher CD8+ T-cell content in the tumor center or periphery, with HRs of 0.58 (0.43-0.94; P=0.02) and 0.39 (0.25-0.59; P Based on these characterizations, tumor immune cell components seem to play important but varying roles in response to dacarbazine or vemurafenib treatment in BRAF-mutant melanoma. This abstract is also being presented as Poster B22. Citation Format: Matthew Wongchenko, Christina Rabe, Jeffrey Sosman, Grant McArthur, Yuanyuan Xiao, Houston Gilbert, Luc Andries, Mark Kockx, Hartmut Koeppen, Priti Hegde, Lukas Amler, Yibing Yan, Antoni Ribas. CD8+ T-cell distribution and immunomodulator expression in BRAF-mutant melanoma affect the response to BRAF inhibitor and chemotherapy. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Melanoma: From Biology to Therapy; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(14 Suppl):Abstract nr PR03.