SNA-125

**SNA-125** is a topical investigational new chemical entity (NCE) developed by Sienna Biopharmaceuticals using their **Topical by Design™** platform, which links a short polyethylene glycol (PEG) polymer to a pharmacologically active molecule to enable high local concentrations in the skin with minimal systemic exposure. It is a **narrow spectrum kinase inhibitor** that potently and selectively inhibits **Janus kinase 3 (JAK3)**, blocking signaling of key cytokines implicated in autoimmune and inflammatory diseases like psoriasis and atopic dermatitis, and **tropomyosin receptor kinase A (TrkA)**, the high-affinity receptor for nerve growth factor (NGF) that mediates neurogenic inflammation and pruritus associated with these conditions. SNA-125 was evaluated in early-stage proof-of-concept trials for **mild-to-moderate psoriasis** (Phase 1/2, showing modest reductions in epidermal thickness and biomarker modulation but no significant change in inflammatory infiltrate) and **atopic dermatitis** (Phase 1/2 ongoing as of 2018, with plans for Phase 2 in 2019), demonstrating good tolerability with no serious safety signals.[1][3][5][9]