Toxicity studies immunotoxicity testing

TABLE 7.7. FDA Draft Recommendation for Type I Immunotoxicity Test That Can Be Included in Repeated Dose Toxicity Studies... 

The standard repeated dose toxicity guidehne studies include a number of parameters relevant for the evaluation of a substance s immunotoxic potential. While some information on potential immunotoxic effects may be obtained from the evaluation of hematology, lymphoid organ weights, and histopathology in these studies, there are data which demonstrate that these endpoints alone are not sufficient to predict immunotoxicity. In addition to these standard studies, the US-EPA has developed a specific test guideline for immunotoxicity testing in rodents (OPPTS 870.7800). This... 

Immunotoxicity testing guidelines exist for small molecules where the toxicology is largely unpredictable and rodent species are typically used [4]. Despite the lack of a specific guidance on immunotoxicity evaluation until now, most biopharmaceuticals have assessed the immunotoxic potential of the biophar-maceutical as a part of general single- and/or repeat-dose toxicity studies [5,23]. 

The TDAR assay is believed to be one of the more predictive functional assays for assessing the immunotoxicity potential of drug candidates. This assay could be used to investigate the functional consequences of alterations seen in repeated-dose toxicity studies and/or clinical trials, and to provide an early read on the immunomodulatory potential of discovery candidates. The TDAR assay has been shown to predict immunotoxicity hazard. However, because of the inherent inter-animal variability seen in the TDAR particularly in outbred species, the assay should not be used as the definitive test but as an integral component of a weight-of-evidence approach for evaluating immunotoxicity risk. 

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