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Hypersensitivity reactions to systemically administered drugs cannot be predicted using available preclinical models. This research is a collaborative project to evaluate the ability of the Lymph Node Proliferation Assay (LNPA) to predict systemic hypersensitivity caused by pharmaceuticals. The assay design is a modification of the Local Lymph Node Assay with the major modification being injection of the test substance subcutaneously to achieve a known systemic exposure to the drug. Fourteen compounds were evaluated in the LNPA. These were two clinically negative drugs (Metformin, phenobarbital), an assay positive control (streptozotocin), eight human hypersensitivity positive drugs (sulfamethoxazole, procainamide, clonidine, ofloxacin, nevirapine, abacavir, lamotrigine, zomepirac), and 3 investigational drugs (CM40874, CM40954 and CM40420), one of which caused hypersensitivity in primates. Hypersensitivity-positive drugs were classified as such based on at least two of three independent data sources: U.S. FDA postmarketing database, drug labeling information, and clinical trial data. All drugs were tested in multiple laboratories for a total of 2–12 evaluations per compound. The pure drug substance was used for testing if it could be obtained commercially, otherwise the marketed drug formulation was used. Neither of the negative control drugs showed a positive reaction in the test system. Four of the eight hypersensitivity positive drugs showed a mixed or positive reaction. Two of the three investigational compounds gave a positive response. A smaller number of LNPAs were run concurrently using footpad injection and evaluation of the popliteal lymph node and gave generally comparable results. Additional development may increase the reproducibility of the assay and facilitate detection of drugs that require metabolic activation to become allergenic, or drugs for which there is dose-limiting toxicity. The data suggest that this method might be useful as a first-line screen to identify candidate drugs that are more likely to cause a high prevalence of human drug hypersensitivity. [ABSTRACT FROM AUTHOR]

The most commonly used assays designed to detect either skin or systemic immune-based hypersensitivity reactions are those using guinea pigs (GP). We obtained data from various FDA records to evaluate the correlation between GP assay results and reported post-marketing systemic hypersensitivity reactions. We examined the new drug application (NDA) reviews of approved drugs for the results of GP assays. Post-marketing human data were extracted from the FDA adverse event reporting system (AERS). Drug usage data were obtained from a commercial database maintained by IMS Health Inc. We found 83 (21%) of 396 drugs approved between 1978 and 1998 had reported GP test results. Among these 83 drugs, 14 (17%) were found to have positive results in at least one GP assay. Simple reporting index (RI) values for systemic hypersensitivity reactions were calculated from AERS data and usage to produce the index of adverse event reports per million shipping units of drug. A variety of definitions of positive human response were examined. A statistically significant association was seen for rash between post-marketing and clinical trials adverse event reports. No statistically significant associations between human data and GP test results were observed. These data suggest that standard GP assays have limited ability to predict human systemic hypersensitivity potential for pharmaceuticals. [Copyright &y& Elsevier]