COR803

COR803 is a novel, patent-pending **small molecule inhibitor** targeting the **3CLpro (main protease, Mpro) of coronaviruses**, including SARS-CoV-2[1][2][3][4][5][6]. COR803 was discovered and developed by Cortexyme (now part of Lighthouse Pharmaceutical’s protease inhibitor portfolio) based on proprietary expertise in **cysteine protease inhibition**[1][2][3][5]. Its mechanism is characterized by **covalent, irreversible binding** to 3CLpro resulting in **high antiviral potency, selectivity**, and broad-spectrum potential due to the highly conserved nature of its target across coronavirus strains[1][2][3]. COR803 demonstrated strong antiviral activity (EC90 of 30 nM in human lung cell viral replication assays)[2], high selectivity for 3CLpro over other proteases (including Cathepsin L)[2], and systemic exposure with oral, intranasal, or subcutaneous administration[1][2][3][4]. It is being developed as a **potential treatment for COVID-19 and other coronavirus infections**, for use at various stages (early outpatient to inpatient)[2][3][6]. Development is currently in IND-enabling preclinical studies[1].