AJX-701

AJX-701 is a selective Janus kinase 1 (JAK1) degrader developed for the treatment of autoimmune and inflammatory diseases. Unlike traditional JAK inhibitors that reversibly block the kinase's enzymatic activity, AJX-701 utilizes a targeted protein degradation (TPD) approach to eliminate the JAK1 protein entirely. This mechanism is designed to achieve superior selectivity for JAK1 over other family members like JAK2, potentially minimizing side effects such as anemia or myelosuppression associated with broader JAK inhibition. The candidate was originally developed by Ajax Therapeutics and was the lead asset in their pipeline at the time of their acquisition by Eli Lilly. It is currently being evaluated in Phase 1 clinical trials for indications including rheumatoid arthritis and inflammatory bowel disease (IBD).