Biologicals used as therapeutics may induce unwanted immune responses in treated patients. Thus, the EMEA has recently issued a guideline for immunogenicity assessment. Immunogenicity testing should be part of clinical efficacy and safety studies.
Key elements of the EMEA recommendations in brief: Immunogenicity should be evaluated in all study participants and not only in symptomatic individuals. Bioassays for neutralizing antibodies need to be designed in a product-dependent manner. Clear criteria have to be defined to distinguish positive from negative findings and to confirm positive results.
FOCUS Immunology supports its clients to integrate these recommendations into their repsective clinical trial protocols. FOCUS’ services comprise assay development and validation for preclinical and clinical studies, testing under GLP conditions, implementation of confirmatory assays, development of bioassays for testing of neutralising antibodies and sample logistics in international multicenter trials.
If you have questions or want to discuss immunogenicity testing in your specific development project, please do not hesitate to contact our Head of the Immunology Laboratory Dr. Eddy Bruyns via email (eddy.bruyns@focus-cdd.com) or via telephone (+49 6221 649 35 124).
The current EMEA guideline on immunogenicity testing can be found here.
The overall intent of exploratory clinical studies is to provide information that allows assessing the clinical feasibility of new drug candidates early in the development process. Exploratory clinical trials therefore aim at early evaluation in humans of pharmacokinetic and and phamacodynamic profiles of novel compounds.
The doses applied in such studies are too low to be therapeutic or even to allow any meaningful PD assessment by conventional methods. Therefore, sensitive and specific (“surrogate”) PD markers – “biomarkers” – are required.
In an expert report, Dr. Eddy Bruyns, Dr. Matthias Baumann and Dr. Maikel Raghoebar of FOCUS have compiled information on the use of biomarkers in exploratory clinical studies and they provide a summary of the pertinent regulatory background.
They point out that PD biomarkers are feasible in many therapeutic areas, yet they are especially useful in the development of drugs for anti-inflammation and immuno-modulation. This is exemplified by several case studies.
To order a complimentary copy of the FOCUS expert report on the use of biomarkers in exploratory clinical studies enter your email address below and press the submit button:
A detailed complimentary copy of FOCUS’ expert report can be ordered by entering your email address below and pressing the submit button:
“FOCUS Immunology Laboratories Heidelberg” offer testing of biomarkers for immune cell functions tailored to the specific requirements of a given clinical trial.
For further information please contact Dr. Eddy Bruyns at eddy.bruyns@focus-cdd.com.
FOCUS used the expertise of its Heidelberg-based subsidiary FOCUS Immunology in an international multi-center clinical trial that required the isolation of immune cells from peripheral blood, their transportation and subsequent testing for cellular functions.
Patients were recruited at medical centers in different countries. FOCUS established a robust and simple protocol for standardized on-site cell preparation and organised the controlled transportation of the cells to the central testing laboratory in Heidelberg.
After appropriate quality control of in-coming samples, isolated immune cells were cultured and tested for various functions including cytokine production and proliferation.
The preparation and implementation of standardized sample generation, sample logistics and testing was completed within 6 weeks.
The studies led to further understanding of patient characteristics and the compound’s mode-of-action.
For further information contact FOCUS’ Head of Immmunology laboratory Dr. Eddy Bruyns via eddy.bruyns@focus-cdd.com or +49 (0) 649 35 124.
There is a medical need for immunostimulatory compounds. In particular novel cancer therapies aim at boosting the immune system to attack and destroy tumors in afflicted patients. CpG-oligos are one result of these research and development efforts.
FOCUS Immunology has established in vivo as well as ex vivo assays to assess the immunostimulatory capacity of compounds.
The ex vivo models provided by FOCUS Immunology allow to explore stimulatory activities at the level of proliferation, cytokine secretion and expression of activation markers in isolated lymphoid or myeloid cells. Defined cell populations may be purified from peripheral blood and used in the respective assay systems. The read-out systems may be at bulk culture level or single cell level.
FOCUS Imunology’s in vivo model for immunostimulation testing uses a suboptimal immunization schedule in mice. Animals are immunized with selected peptides in the presence or absence of the test-compound and at specified points in time the extent of the ensuing immune response is analyzed by measuring the frequency of antigen-specific responding cells upon in vitro restimulation with peptide in the EliSpot assay and by quantifying IFN-gamma from the serum of animals.
The specific or adaptive immune system comprises T and B lymphocytes. FOCUS Immunology provides assays to analyze the activity of these cells.
Cytokine secretion or proliferation is assessed in bulk cultures, or alternatively at the single cell level by single cell analysis techniques. The latter techniques offered by FOCUS Immunology are EliSpot or ICS (Intracellular Cytokine Staining) to analyze cytokine secretion on the single cell level or the flow cytometry-based CFSE assay to determine proliferation of individual T or B cells.
Prior to analysis the cells may be stimulated polyclonally by using PHA, PMA + Ionomycin, or antibodies directed against CD3 and CD28. Or the cells may be stimulated in an antigen-specific manner by using CMV (Cytomegalovirus) antigens and Tetanus Toxoid.
For many of the assays it is possible to select different cell populations to start with such as whole blood, purified peripheral blood mononuclear cells (PBMC), or selected lymphoid subpopulations such as B cells, T cells, CD4+cells or regulatory T cells and so on.
Specifically, FOCUS Immunology performs the following tests to determine effects of compounds on cells of the specific immune system:
(i) Proliferation assays to determine the proliferation rate of T or B lymphocytes. Upon antigen-specific or non-specific stimulation, cell proliferation will be determined either in bulk cultures by metabolic assays (MTS or ATP-dependent) or by measuring DNA synthesis (BrdU incorporation).
Alternatively, cell proliferation may be determined on the single cell level using the CFSE assay. Hereby, cells are labelled with CFDA-SE (carboxyfluorescein diacetate succinimidyl ester), a cell-permeable, non-fluorescent compound, which is converted by intracellular esterases to the fluorescent and non-membran-permeable CFSE (carboxyfluorescein succinimidyl ester). This molecule is highly stable and is distributed during cell division evenly to the daughter generations. Thus, flow cytometry allows to track proliferation of stimulated lymphocytes through consecutive generations.
(ii) Flow cytometry assays to analyze functional states of lymphocytes. T and B lymphocytes are not only characterized by lineage-specific markers such as CD3 for T cells and CD19 or CD20 for B cells but also by a continuously growing panel to distinguish subpopulations. CD4 and CD8 for helper and cytotoxic T cells and CD4,CD25 for regulatory T cells are just a few examples.
Additionally, cells of the lymphoid lineage acquire specific activation markers upon stimulation, which are not expressed on resting cells. Among these are CD69, CD25 and CD86.
A combination of lineage and activation markers allows analyzing the functional states of lymphoid cells on the single cell level, which thus allows analyzing the effects test-compounds on the functionality of lymphoid subpopulation.
FOCUS Immunology uses a dual-laser FACSCalibur from BD Biosciences to analyze up to four different markers in parallel allowing a detailed analysis of cell surface and/or intracellular markers.
(iii) Analysis of cytokine induction. Upon antigen-specific or non-specific stimulation cytokine production will be measured using either of three assays:
(a) ELISA, to determine the total amount of cytokine(s) secreted into the cell culture medium,
(b) EliSpot, to determine the frequency of cells secreting (a) particular cytokine(s), and
(c) Intracellular Cytokine Staining (ICS), to measure multiple cytokines and correlate their expression on the single cell level with lineage markers.
Monday, May 18, 2009
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