Core Insights - Septerna, Inc. has initiated the Phase 1 clinical trial for SEP-631, a selective oral small molecule MRGPRX2 negative allosteric modulator aimed at treating chronic spontaneous urticaria (CSU) and other mast cell-driven diseases [1][2][4] Company Overview - Septerna is a clinical-stage biotechnology company focused on G protein-coupled receptor (GPCR) drug discovery, utilizing its proprietary Native Complex Platform™ to develop novel oral small molecule drug candidates [5] - The company aims to address significant unmet medical needs in various therapeutic areas, including endocrinology, immunology, inflammation, and metabolic diseases [5] Clinical Trial Details - The Phase 1 clinical trial will consist of a single-ascending dose (SAD) and multiple-ascending dose (MAD) study, enrolling approximately 150 healthy adult volunteers to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of SEP-631 [3] - The SAD portion is currently underway, focusing on escalating oral doses, while the MAD portion will assess the safety and tolerability over a treatment period [3] Disease Context - Mast cell-driven diseases, such as CSU, affect millions globally and often result in inadequate symptom relief from existing therapies, highlighting the need for new treatment options [2] - CSU is characterized by spontaneous and persistent hives and angioedema, with mast cell activation playing a critical role in symptom development [2][4]