Cmpd B

Cmpd B is a potent and highly selective small molecule inhibitor of Janus Kinase 1 (JAK1), developed by AstraZeneca for preclinical research. It demonstrates greater than 600-fold selectivity for JAK1 over JAK2 and JAK3. In the context of Alopecia Areata (AA) research, Cmpd B was employed as a tool compound to evaluate the efficacy of localized treatment. Formulated as a 0.1% topical cream, it was designed for high skin retention with minimal systemic absorption. Preclinical studies in the C3H/HeJ mouse model indicated that while Cmpd B effectively targeted the skin, local inhibition alone was insufficient to restore hair growth, highlighting the necessity of systemic JAK1 inhibition to address the underlying immune dysregulation in AA.