SOUTH SAN FRANCISCO, Calif. — August 21, 2025 — Leads & Copy — Septerna, Inc. (Nasdaq: SEPN) has dosed the first participants in its Phase 1 clinical trial of SEP-631, an oral small molecule Mas-related G protein-coupled receptor X2 (MRGPRX2) negative allosteric modulator (NAM) for chronic spontaneous urticaria (CSU) and other mast cell-driven diseases.
The Phase 1 trial will evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of SEP-631 in healthy adult volunteers.
CSU, a systemic inflammatory skin disease, affects millions who often struggle with symptom relief. SEP-631 aims to inhibit mast cell activation by selectively blocking MRGPRX2.
The randomized, placebo-controlled Phase 1 trial is expected to enroll up to approximately 150 healthy adult volunteers.
SEP-631 has demonstrated potent and long-lasting inhibition of MRGPRX2 in preclinical studies.
Renee Leck, THRUST, renee@thrustsc.com
Carly Scaduto, carly@carlyscadutoconsulting.com
Source: Septerna, Inc.
