ARQ-250 is a potent and highly selective topical, small molecule inhibitor of janus kinase type 1 (JAK1). Many inflammatory cytokines and other signaling molecules rely on the JAK pathway, and specifically JAK1, which plays a central role in immune system function. Inhibition of JAK1 has been shown to treat a range of inflammatory diseases, including rheumatoid arthritis, psoriasis, Crohn’s disease, and atopic dermatitis. We believe that due to its high selectivity for JAK1 over JAK2, ARQ-250 will be able to effectively treat inflammatory diseases without causing the hematopoietic adverse effects typically associated with JAK2 inhibition. Currently, ARQ-250 is in preclinical development.