Development of the RXR agonist IRX4204 to treat Multiple Sclerosis and other Immu

DESCRIPTION (provided by applicant): Io Therapeutics is developing a novel agonist for the Retinoid X Receptors (RXR), IRX4204, to treat multiple sclerosis (MS) and other autoimmune diseases. RXR is a key nuclear receptor involved in inflammation. It has arole in regulating immunity through the enhancement of Treg activities and suppression of inflammatory Th17 activities. Because of the importance of RXR in controlling immunity, small molecule agonists and antagonists for these nuclear receptors have become attractive drug candidates. Io developed IRX4204 as a second-generation RXR specific agonist that belongs to the rexinoid class of compounds. It binds with very high affinity and selectivity to the RXRs, IRX 4204 has very limited affinity for the Retinoic Acid Receptors (RAR). In functional transactivation assays, IRX4204 is at least 2,000 fold more potent in activating RXR homodimers than RAR-RXR heterodimers and IRX4204 does not activate other heterodimers such as RXR-PPAR , RXR-LXR, and RXR-FXR.