The pathogenesis of Gram-negative septic shock, a leading cause of mortality in critically ill patients, is a consequence of the overwhelming innate immune response to endotoxins, or lipopolysaccharides (LPS), present on the surface of Gram-negative bacteria (including Category A and B Select Agents). We have shown that relatively simple and synthetically easily accessible molecules of the lipopolyamine class specifically bind to the toxic "Lipid A" moiety of LPS and neutralize its toxicity. Extensive structure-activity relationship studies on lipopolyamines using a combination of classical medicinal chemistry approaches, combinatorial lead generation, molecular modeling, high-throughput screening, and the development of novel secondary and tertiary-level assays to verify the premise of true sequestration of LPS by these compounds in vitro as well as in animal models have led to the identification of DS-96, an N- alkylhomospermine derivative. The in vitro and in vivo LPS-sequestering and -neutralizing properties of DS- 96 rival that of polymyxin B, a gold standard LPS sequestrant in every respect thus far. Importantly, in all of our in vivo studies to date, we have been unable to detect any apparent toxicity for DS-96. We propose to further the preclinical development of DS-96, establish efficacy in alternate animal models of endotoxic shock, characterize its safety profile, and obtain detailed pharmacokinetic and ADME data.
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