Bioasis Technologies Inc. announced positive results from an efficacy study of a blood-brain barrier penetrant interleukin-1 receptor inhibitor in a preclinical rodent model of multiple sclerosis. In previously published work, a recombinant fusion protein of the company’s proprietary xB3™ peptide with an interleukin-1 receptor antagonist (xB3™-IL-1RA) demonstrated efficient delivery of effective concentrations of IL-1RA to the brain eliciting analgesia in a neuropathic pain animal model. Systemic administration of IL-1RA alone did not elicit analgesia. Since IL-1 cytokines have been implicated in many autoimmune and neuroinflammatory diseases, xB3™-IL-1RA was investigated disease in the rodent experimental allergic encephalomyelitis (EAE) model of multiple sclerosis. Multiple doses of xB3™-IL-1RA were administered during the disease induction phase, resulting in both delayed onset and overall reduced clinical symptom score in animals treated with xB3™-IL-1RA compared to control animals (p<0.016 repeated measures ANOVA). The data from this study provides further evidence for the utility of xB3™ peptide as a platform technology for delivery of large molecule biologics across the BBB. Furthermore, this study confirms the potential applicability of xB3™-IL-1RA to the treatment of neuroinflammatory diseases such as multiple sclerosis.