AB0199 GENES PREDICTIVE ON THE EFFICACY OF INFLIXIMAB IN THE TREATMENT OF RHEUMATOID ARTHRITIS: A PROSPECTIVE, MULTI-CENTRE, CLINICAL PERFORMANCE EVALUATION STUDY FOR AN IN-VITRO DIAGNOSTICS MEDICAL DEVICE

Background:

Approximately 30% of rheumatoid arthritis (RA) patients fail to respond to first biological therapy, thus treatment selection of biologic therapy for patients with RA is of high importance. The lack of biomarkers to predict specific biological treatment response, in the case of non-responder (NR) patients leads to unnecessary exposure, delay of adequate therapy, progression of the disease and therapy cost increase. Predicting the patient’s responsiveness to the first biological therapy is still an unmet need in the clinical setting. Predictive in vitro testing would have a significant effect on the administration of biological therapy, on the real life implementation of cost effective personalized therapy.

Objectives:

The purpose of this in vitro diagnostic medical device study was to demonstrate that particular gene expression profiles as genomic biomarkers (i.e. the IVD medical device) predict therapeutic response to infliximab, discriminate between responders and non-responders to infliximab treatment. Responders were defined if they reached DAS target value DAS28≤3.2 at 6 month (M6).

Methods:

110 bionaive patients were enrolled with moderate-high activity RA (DAS28-CRP >3.2), who have responded inadequately to DMARDs (including methotrexate), after they have been assigned to infliximab treatment. All patients received commercially available infliximab, procured according to SmPC, local guidelines and regulations in this non-interventional clinical study. The clinical response was evaluated according to the change from baseline in disease activity at M6. Clinical characteristics (RA duration, smoke, steroid treatment, etc.) and serological parameters (RF, ACPA, aCVM) were collected. A 3rdvisit scheduled around week 22 (M6) and change of DAS28-CRP value from the baseline has been evaluated. Gene expression profiling was performed from blood samples taken at month 0 (M0); - just before the first infliximab infusion. Global gene expression profiling was performed to identify differentially expressing genes using RNA sequencing. The set of differentially expressing genes were further reduced with a combination of machine learning modelling and various feature elimination methods. The expression of the reduced gene set was confirmed and further analysed using reverse-transcription and quantitative real-time PCR.

Results:

A total of 250 genes were identified by a combination of differential gene expression analyses, feature elimination techniques and various machine learning modelling methods of which 44 genes showed significant differences between NR and good responder groups. Preliminary interim analysis identified associations between gene expression and clinical response/ non-response to infliximab therapy.

Table.

Three models containing gene expression + clinical data sets illustrates some statistical characteristics

Modell building_IDAccuracySensitivitySpecificityModell VerificationAccuracySensitivitySpecificity00232100.00100.00100.00002328888.8987.5000249 98.82 96.55100.00002498477.7887.5000270 98.82 96.55100.00002708877.7893.75

Conclusion:

Our preliminary analysis shows that this set of genes and selected clinical parameters are predictive markers for infliximab specific response in RA patients. Ongoing work involves the clinical validation of these results in an independent patient cohort (n=60). This approach provides the opportunity to develop an in vitro diagnostic test method for the prediction of infliximab treatment responsiveness in bionaive rheumatod arthritis patients, hence to personalize infliximab therapy for these patients.

Disclosure of Interests:

Emese Kiss Consultant of: EK has received consultancy fees from Egis., Gyula Poór Consultant of: GyP has received consultancy fees from Egis and he was the coordinating investigator in this study, Gábor Zahuczky Grant/research support from: Egis, Katalin Tauberné Jakab Employee of: Egis., Miklós Sebeszta Employee of: Egis., Tamás Ponyi Employee of: Egis., Zsolt Holló Employee of: Egis.

Decreased apopto-phagocytic gene expression in the macrophages of systemic lupus erythematosus patients

The clearance of apoptotic cells has an important role in the maintenance of tissue homeostasis and in the protection of tissues from the inflammatory and immunogenic contents of dying cells. A defect in the recognition and phagocytosis of apoptotic cells contributes to the development of chronic inflammation and autoimmune disorders. We have observed that compared with healthy donors, differentiated macrophages from patients with untreated systemic lupus erythematosus (SLE) showed decreased phagocytosis of apoptotic neutrophils. A TaqMan Low Density Array was designed to determine the mRNA expression levels of 95 apopto-phagocytic genes in differentiated non-phagocytosing and phagocytosing macrophages. In the macrophages of clinically and immunoserologically active SLE patients, 39 genes were expressed at lower levels than in the control macrophages. When inactive patients were compared with those with minor immunoserological abnormalities or patients in an immunoserologically active state, a relationship was observed between the altered gene expression profile and the disease state. In the macrophages of patients with engulfing apoptotic cells, an upregulation of genes involved in inflammation, autophagy, and signaling was observed. These results indicate that novel immune-pathological pathways are involved in SLE and suggest targets for potential therapeutic modulation.

Peripheral blood derived gene panels predict response to infliximab in rheumatoid arthritis and Crohn's disease

Background

Biological therapies have been introduced for the treatment of chronic inflammatory diseases including rheumatoid arthritis (RA) and Crohn's disease (CD). The efficacy of biologics differs from patient to patient. Moreover these therapies are rather expensive, therefore treatment of primary non-responders should be avoided.

Method

We addressed this issue by combining gene expression profiling and biostatistical approaches. We performed peripheral blood global gene expression profiling in order to filter the genome for target genes in cohorts of 20 CD and 19 RA patients. Then RT-quantitative PCR validation was performed, followed by multivariate analyses of genes in independent cohorts of 20 CD and 15 RA patients, in order to identify sets ofinterrelated genes that can separate responders from non-responders to the humanized chimeric anti-TNFalpha antibody infliximab at baseline.

Results

Gene panels separating responders from non-responders were identified using leave-one-out cross-validation test, and a pool of genes that should be tested on larger cohorts was created in both conditions.

Conclusions

Our data show that peripheral blood gene expression profiles are suitable for determining gene panels with high discriminatory power to differentiate responders from non-responders in infliximab therapy at baseline in CD and RA, which could be cross-validated successfully. Biostatistical analysis of peripheral blood gene expression data leads to the identification of gene panels that can help predict responsiveness of therapy and support the clinical decision-making process.

The triad of success in personalised medicine: pharmacogenomics, biotechnology and regulatory issues from a Central European perspective

The population of the world has recently passed the 7 billion milestone and as the cost of human genome sequencing is rapidly declining, sequence data of billions of people should be accessible much sooner than anyone would have predicted 10 years ago. This will form the basis of personalised medicine. However it is still not clear, even in principle, whether these data, combined with data of the expression of one's genome in various cells and tissues relevant to different diseases, could be used effectively in clinical medicine and healthcare, or in predicting responses to different therapies. Therefore this is an important issue which needs to be addressed before more resources are wasted on less than informative studies and surveys simply because technologies exist. As a typical example, we have selected and summarise here key studies from the biomedical literature that focus on gene expression profiling of the response to biologic therapies in peripheral blood and biopsy samples in autoimmune diseases such as rheumatoid arthritis, spondylarthropathy, inflammatory bowel diseases and psoriasis. We also present the state of the biotechnology market from a European perspective, discuss how spin-offs leverage the power of genomic technologies and describe how they might contribute to personalised medicine. As ethical, legal and social issues are essential in the area of genomics, we analysed these aspects and present here the European situation with a special focus on Hungary. We propose that the synergy of these three issues: pharmacogenomics, biotechnology and regulatory issues should be considered a triad necessary to succeed in personalised medicine.

Expression of invasion-related extracellular matrix molecules in human glioblastoma versus intracerebral lung adenocarcinoma metastasis

Tumor cell invasion into the surrounding brain tissue is mainly responsible for the failure of radical surgical resection, with tumor recurrence in the form of microdisseminated disease. Extracellular matrix (ECM)-related molecules and their receptors predominantly participate in the invasion process, including cell adhesion to the surrounding microenvironment and cell migration. The extent of infiltration of the healthy brain by malignant tumors strongly depends on the tumor cell type. Malignant gliomas show much more intensive peritumoral invasion than do metastatic tumors. In this study, the mRNA expression of 30 invasion-related molecules (twenty-one ECM components, two related receptors, and seven ECM-related enzymes) was investigated by quantitative reverse transcriptase-polymerase chain reaction. Fresh frozen human tissue samples from glioblastoma (GBM), intracerebral lung adenocarcinoma metastasis, and normal brain were evaluated. Significant differences were established for 24 of the 30 molecules. To confirm our results at the protein level, immunohistochemical analysis of seven molecules was performed (agrin, neurocan, syndecan, versican, matrix metalloproteinase 2 [MMP-2], MMP-9, and hyaluronan). Determining the differences in the levels of invasion-related molecules for tumors of different origins can help to identify the exact molecular mechanisms that facilitate peritumoral infiltration by glioblastoma cells. These results should allow the selection of target molecules for potential chemotherapeutic agents directed against highly invasive malignant gliomas.

Clearance of dying autophagic cells of different origin by professional and non-professional phagocytes

MCF-7 cells undergo autophagic death upon tamoxifen treatment. Plated on non-adhesive substratum these cells died by anoikis while inducing autophagy as revealed by monodansylcadaverine staining, elevated light-chain-3 expression and electron microscopy. Both de novo and anoikis-derived autophagic dying cells were engulfed by human macrophages and MCF-7 cells. Inhibition of autophagy by 3-methyladenine abolished engulfment of cells dying through de novo autophagy, but not those dying through anoikis. Blocking exposure of phosphatidylserine (PS) on both dying cell types inhibited phagocytosis by MCF-7 but not by macrophages. Gene expression profiling showed that though both types of phagocytes expressed full repertoire of the PS recognition and signaling pathway, macrophages could evolve during engulfment of de novo autophagic cells the potential of calreticulin-mediated processes as well. Our data suggest that cells dying through autophagy and those committing anoikis with autophagy may engage in overlapping but distinct sets of clearance mechanisms in professional and non-professional phagocytes.

Comparison of the substrate specificity of the human T-cell leukemia virus and human immunodeficiency virus proteinases

Human T-cell leukemia virus type-1 (HTLV-1) is associated with a number of human diseases. Based on the therapeutic success of human immunodeficiency virus type 1 (HIV-1) PR inhibitors, the proteinase (PR) of HTLV-1 is a potential target for chemotherapy. To facilitate the design of potent inhibitors, the subsite specificity of HTLV-1 PR was characterized and compared to that of HIV-1 PR. Two sets of substrates were used that contained single amino-acid substitutions in peptides representing naturally occurring cleavage sites in HIV-1 and HTLV-1. The original HIV-1 matrix/capsid cleavage site substrate and most of its substituted peptides were not hydrolyzed by the HTLV-1 enzyme, except for those with hydrophobic residues at the P4 and P2 positions. On the other hand, most of the peptides representing the HTLV-1 capsid/nucleocapsid cleavage site were substrates of both enzymes. A large difference in the specificity of HTLV-1 and HIV-1 proteinases was demonstrated by kinetic measurements, particularly with regard to the S4 and S2 subsites, whereas the S1 subsite appeared to be more conserved. A molecular model of the HTLV-1 PR in complex with this substrate was built, based on the crystal structure of the S9 mutant of Rous sarcoma virus PR, in order to understand the molecular basis of the enzyme specificity. Based on the kinetics of shortened analogs of the HTLV-1 substrate and on analysis of the modeled complex of HTLV-1 PR with substrate, the substrate binding site of the HTLV-1 PR appeared to be more extended than that of HIV-1 PR. Kinetic results also suggested that the cleavage site between the capsid and nucleocapsid protein of HTLV-1 is evolutionarily optimized for rapid hydrolysis.

Cloning of the bovine leukemia virus proteinase in Escherichia coli and comparison of its specificity to that of human T-cell leukemia virus proteinase

The proteinase of bovine leukemia virus (BLV) was cloned into pMal-c2 vector with N-terminal or with N- as well as C-terminal flanking sequences, and expressed in fusion with maltose binding protein. The proteinase self-processed itself from the fusion protein during expression and formed inclusion bodies. The enzyme was purified from inclusion bodies by cation-exchange chromatography followed by gel filtration. Specificity of the enzyme was compared to that of human T-cell leukemia proteinase type 1. Although the two viruses belong to the same subfamily of retroviruses, the differences in their proteinase specificity, based on kinetics with oligopeptide substrates representing naturally occurring cleavage sites as well as on inhibition pattern, appear to be pronounced.