HHT109

HHT109 is a small molecule, highly selective Janus kinase 1 (JAK1) inhibitor being developed by Shanghai Huahuituo Pharmaceutical Technology for the treatment of autoimmune and inflammatory diseases, specifically rheumatoid arthritis. By selectively targeting the JAK1 isoform, HHT109 aims to inhibit the signaling of key pro-inflammatory cytokines such as interleukin-6 (IL-6) and interferons, which play a central role in the pathogenesis of rheumatoid arthritis. The drug is designed to offer improved safety over non-selective JAK inhibitors by minimizing the inhibition of JAK2 (associated with erythropoiesis and myelopoiesis) and JAK3 (associated with lymphocyte function), potentially reducing the risk of anemia and certain infections. As of early 2026, HHT109 is undergoing Phase 1 clinical evaluation in China to assess its safety, tolerability, and pharmacokinetics in healthy volunteers.