Suramin for Recluse Spider Bites: SpiderTek, a biotechnology company that developed the first spider bite diagnostic test, proposes therapy for bites due to Loxoscelesthre erecclulseusspiade,r, using suramin, a century-old treatment for African sleeping sickness. A population of 80 million in the South-Central US shares homes with the recluse spider. Each year, an estimated 30,000 persons suffer recluse spider bites that can result in painful, slowly healing wounds. Hundreds of patients annually develop hemolysis, which can be severe, especially in children and older persons. Therapy in the United States is limited to supportive measures. With accurate diagnosis now available, the next step is to develop an effective treatment. We propose a therapeutic solution based on the discovery that the suramin molecule binds to phospholipase D, the active component in the recluse spider venom. The overall objective of the proposed research is to develop an optimized therapy for these spider bites. Phase I will determine the therapeutic constraints of suramin therapy in loxoscelism. First, we will determine the range of the effective in-vivo dose as we vary suramin dose. Next, we will determine the time window for effective treatment—how soon after the bite does treatment have to occur to be effective? Finally, we will compare suramin injection with a novel topical administration technique, which will enable patients to avoid emergency room visits. The proposed research will provide basic proof-of-concept for our proposed suramin therapy for loxoscelism and enable us to develop a human trial in planned Phase II research. Finally, our interdisciplinary research team involves collaboration between privately held SpiderTek and the University of Missouri. Both entities are located in rural Missouri, where the incidence of loxoscelism is high. The team features multidisciplinary expertise, including an animal scientist, developer of the first ELISA-based pregnancy test for cattle as well as our spider bite diagnostic test, a dermatologist with extensive experience in recluse spider bites, and a widely recognized developer of topical formulations. With previous successful experience in bringing the first spider bite test to market and with strong existing collaborations between the principal investigator and his colleagues, the team is uniquely positioned to perform the proposed research.