Ulcerative colitis (UC) is a chronic, relapsing disease characterized by inflammation and ulceration of the colon and rectum that affects approximately 1.5 million people in the United States. While the precise etiology of UC is unknown, it is thought to result from an inappropriate inflammatory response to commensal gut bacteria in genetically susceptible individuals. All cases of UC are characterized by the overproduction of pro-inflammatory mediators and the infiltration of activated immune cells leading to a prolonged inflammatory response. Inflammation resolution is actively controlled by a class of lipid autacoids known as Specialized Pro-resolving Mediators (SPMs). Resolvin E1 (RvE1) is an SPM that impacts multiple pathophysiological mechanisms underlying UC and has demonstrated efficacy in multiple animal models of UC. Thetis Pharmaceuticals is developing TP-317, a first-in-class, oral Resolvin E1 (RvE1) therapy for the induction and maintenance of remission in UC patients. TP-317 is an innovative and patented new molecular entity with enhanced stability compared to RvE1 as the natural substance. Under a prior NIH SBIR Fast Track grant (RDK116460-01 and RDK116460-02) completed in 2021, Thetis successfully conducted multiple investigational new drug (IND)-enabling studies with TP-317, including efficacy and pharmacokinetic studies, non-clinical toxicology and development and scale-up of a proprietary process for TP-317 synthesis. Following the completion of this research, TP-317 formulated as an enteric-coated tablet was investigated in healthy subjects in a single-blind, randomized, Phase 1a single ascending dose study that showed a favorable safety, tolerability and pharmacokinetic profile. The goal of this Phase IIB SBIR program is to complete key non-clinical toxicology studies to enable rapid advancement of TP-317 into Phase 1b and Phase 2 clinical trials in UC patients as summarized below: Aim 1: Investigate TP-317 in Sub-chronic Toxicology Study in Rat (Year 1). We will conduct a 13-week GLP toxicology and toxicokinetic (TK) study in Sprague Dawley Rat with TP-317 administered via oral gavage. Aim 2: Investigate TP-317 in Sub-chronic Toxicology Study in Dog (Year 2). We will conduct a 13-week GLP toxicology and TK study in Beagle dog with TP-317 administered via oral gavage. Aim 3: Investigate TP-317 in Chronic Toxicology Study in Dog (Year 3). We will conduct a 39-week GLP toxicology and TK study in Beagle dog with TP-317 administered via oral gavage.