BRM423 is also a novel synthetic peptide derived from a human Pigment Epithelium-Derived Factor (PEDF). Its drug substance/drug product is the same as the IND drug BRM421, with a different indication of severe corneal damage. BRM423’s safety and early on-set efficacy were shown in two clinical studies of BRM421. In animal studies, BRM423 also demonstrated its effect in corneal damage repair. 

Under the condition of corneal damage, the corneal renewal and repair are supported by limbal stem cells (LSCs) that reside in the limbus. In the case when LSCs are insufficient or dysfunctional, corneal damage cannot be healed and may cause blindness. Losing LSCs due to diseases or accidents is the most common cause for blindness.

BRM423’s PEDF-derived short peptide (PDSP) was previously shown to promote growth, expansion and regeneration of LSCs. Furthermore, PDSP-expanded LSCs maintain their ability to differentiate into corneal cells as well as the ability of self-renewal. Most importantly, PDSP significantly accelerated corneal wound healing in animal models, and demonstrated the corneal re-epithelialization function of PEDF, which may also promote LSCs expansion.