Summary of a workshop on nonclinical and clinical immunotoxicity assessment of immunomodulatory drugs.
ABSTRACT The number of anti-inflammatory and immunomodulatory drugs being developed in the pharmaceutical industry has increased considerably in the past decade. This increase in research and development has been paralleled by questions from both regulatory agencies and industry on how best to assess decreased host resistance to infections or adverse immunostimulation caused by immunomodulatory agents such as anti-cytokine antibodies (e.g., the tumor necrosis factor-alpha inhibitors), anti-adhesion molecule antibodies (e.g., anti-alpha-4 integrin inhibitors) and immunostimulatory molecules (e.g., anti-CD28 antibodies). Although several methods have been developed for nonclinical assessment of immunotoxicity, highly publicized adverse events have brought to light significant gaps in the application of nonclinical immunotoxicity testing in assessing potential risk in humans. Confounding this problem is inconsistent application of immunotoxicology methods for risk assessment within the scientific community, limited understanding of appropriate immunotoxicity testing strategy for immunomodulators and inconsistent testing requests by regulatory agencies. To address these concerns, The Immunotoxicology Technical Committee (ITC) of the International Life Science Institute (ILSI) Health and Environmental Sciences Institute (HESI) organized a workshop on Immunomodulators and Clinical Immunotoxicology in May 2007. The Workshop was convened to identify key gaps in nonclinical and clinical immunotoxicity testing of anti-inflammatory and immunomodulatory agents and to begin to develop consistent approaches for immunotoxicity testing and risk assessment. This paper summarizes the outcome of the HESI ITC Immunomodulators and Clinical Immunotoxicology Workshop. Topics not discussed at the Workshop were outside the scope of this report. Although more work is needed to develop consistent approaches for immunotoxicity assessment of immunomodulators, this Workshop provided the foundation for future discussion.
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ABSTRACT: The immunomodulatory effects of clozapine (CLZ), antipsychotic drug, were investigated in vivo using female Balb/c mice. The main aim of this study was to evaluate the immunomodulatory effects of CLZ, antipsychotic drug, following daily intraperitoneal injection to female Balb/c mice over a period of 21 days. Mice were divided into five groups, eight animals per group. Group I, served as a control group, received only the vehicle. Groups II-V received a daily intraperitoneal dose of CLZ (1, 5, 10 and 20 mg/kg, respectively) over a period of 21 days. CLZ has shown a significant decrease in the animal body weight, and it showed a significant decrease in the percentage of circulating neutrophils and lymphocytes while circulating monocytes were increased. The immunotoxicity has been also assessed by evaluating spleen cellularity, humoral immune response to a foreign antigen using sheep red blood cells and delayed-type hypersensitivity reaction. The results showed a marked suppression in these responses in CLZ-treated mice compared with the control group. Detectable changes have also been noticed in the histology of the footpad tissue and spleen. Results showed significant immunomuodulatory effects of CLZ when used in Balb/c mice.12/2013; DOI:10.1111/jphp.12150
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ABSTRACT: AIM: To characterize performance of a complementary set of assays to measure antigen-specific immune responses in subjects immunized with a neoantigen. METHODS: Healthy volunteers (HV) (n=8) and SLE patients (n=6) were immunized with keyhole limpet hemocyanin (KLH) on days 1 and 29. Serum antibodies were detected using a flow cytometric bead array (CBA) that multiplexed the KLH response alongside pre-existing anti-tetanus antibodies; peripheral blood mononuclear cells were studied by B cell ELISPOT. These assays were built upon precedent assay development in cynomolgus monkeys, which pointed towards their utility in humans. RESULTS: Primary anti-KLH IgG responses rose to a mean of 65 - 93 fold above baseline for HV and SLE patients, respectively, and secondary responses rose to a mean of 260 - 170 fold above baseline. High levels of anti-tetanus IgG were detected in pre-immunization samples; their levels did not change over the course of study. Anti-KLH IgG1-4 subclasses were characterized by a predominant IgG1 response, with no significant differences in subclass magnitude or distribution between HV and SLE subjects. Anti-KLH IgM levels were detectable, although the overall response was lower; IgM was not detected in two SLE subjects that did generate an IgG response. All subjects responded to KLH by B cell ELISPOT, with no significant differences observed between HV and SLE subjects. CONCLUSION: The CBA and B cell ELISPOT assays reliably measured anti-KLH B cell responses, supporting use of this approach and these assays to assess the pharmacodynamic and potential safety impact of marketed / investigational immune-therapeutics.British Journal of Clinical Pharmacology 06/2013; 76(2). DOI:10.1111/bcp.12172 · 3.69 Impact Factor
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ABSTRACT: The ICH S8 immunotoxicity testing guideline for human pharmaceuticals was published in 2006 and was intended to provide guidance for assessing the immunotoxicity potential of low-molecular-weight drugs that are not intended to alter the immune system. For drugs intended to modulate the immune system, immunotoxicity testing strategies are generally developed on a case-by-case approach since the targets, intended patient population, and mechanisms of action of the test compound will determine the type of testing needed. Some of the general principles of ICH S8, however, may be applied to immunotoxicity testing strategies for immunomodulatory drugs. A weight-of-evidence approach using factors discussed in ICH S8 in concert with an assessment of the potential value of additional immunotoxicity testing should be considered. For most situations, immunotoxicity studies with immunomodulatory compounds evaluate off-target effects on the immune system and exaggerated pharmacology. The potential use of data from these studies and considerations such as translatability to humans are discussed.Toxicologic Pathology 01/2012; 40(2):288-93. DOI:10.1177/0192623311430238 · 1.92 Impact Factor