Preclinical Pharmacokinetics, ADME, and Drug-Drug Interaction Evaluation of S024, a Novel p38/MK2 Inhibitor for Rheumatoid Arthritis

Introduction: S024 is a novel dual p38/MK2 inhibitor with therapeutic potential for rheumatoid arthritis (RA). Unlike existing RA therapies often limited by suboptimal efficacy and safety profiles, S024 selectively targets the p38/MK2 signaling complex, representing a mechanistically distinct treatment strategy. This study aimed to systematically characterize the preclinical pharmacokinetic (PK), absorption, distribution, metabolism, excretion (ADME), and drug-drug interaction (DDI) profiles of S024. Methods: Permeability was assessed using Caco-2 cell monolayers. PK and oral bioavailability were determined in Sprague-Dawley (SD) rats and beagle dogs. Plasma protein binding (PPB), tissue distribution, in vitro metabolic stability (across species), enzyme phenotyping, excretion mass balance, and DDI potential against major CYP450 enzymes and key ABC/SLC transporters were comprehensively evaluated. Results: values generally exceeding predicted therapeutic concentrations. Conclusion: S024 demonstrated favorable preclinical PK/ADME properties, characterized by robust oral absorption, moderate PPB, extensive distribution, and a low predicted clinical DDI risk. These findings strongly support its further development as a promising clinical candidate for RA therapy.