PROJECT SUMMARY/ABSTRACT This multidisciplinary translational research project has generated a humanized monoclonal antibody (mAb) with high affinity for cocaine (Kd = 4 nM) and specificity over cocaine's inactive metabolites. This unique new molecular entity (preclinical designation, h2E2) consists of a human gamma 1 (?1) heavy chain and humanized lamda (?) light chain with a human constant region and murine variable region. The h2E2 mAb has approximately 95% sequence identity with a human IgG1 isotype. This antibody is at an advanced stage of preclinical development for eventual use in the prevention of relapse in treatment-seeking cocaine abusers. The human sequence of this mAb should confer safety and long-term efficacy in clinical use. Anti-cocaine mAbs bind to and sequester cocaine in the peripheral circulation and we have shown that h2E2 dramatically lowers brain cocaine concentrations in mice and in rats. Furthermore, h2E2 antagonizes the effect of cocaine in a rat model of relapse. Our industry collaborator, Catalent Inc., has used their GPEx technology to produce a series of mammalian cell lines that have exceeded the established production milestone as demonstrated by an initial 10 liter production that run provided 5.7 grams of purified recombinant h2E2. This recombinant mAb has met the established go-no go criteria set by our comprehensive battery of in vitro and in vivo tests of efficacy and is our lead candidate. Work can now proceed to select the best producing cell line to serve as our production platform for commercialization of this immunotherapeutic agent. The establishment of a Master Cell Bank, a Working Cell Bank and a GMP-compliant production platform is proposed that will provide the required quantities of purified h2E2. The overall goal o the proposed studies is to provide the comprehensive in vitro human tissue cross-reactivity studies, the in vivo single-dose toxicology studies and the in vivo efficacy studies in animal models of cocaine relapse and addiction that are required for inclusion in an Investigational New Drug (IND) application to the FDA.