VX-509
(Inflammatory Diseases)

VX-509 is an investigational oral medicine being developed by Vertex that is designed to selectively inhibit Janus kinase 3, or JAK3. JAK3 is one of four JAK family kinases, which include JAK1, JAK2, JAK3 and Tyk2. In autoimmune diseases, JAK3 is believed to be an essential component of the signaling cascade that contributes to the abnormal immune response that results in chronic inflammation and, in the case of RA, irreversible damage to cartilage and bones. Specific inhibition of JAK3 represents a new potential approach to the treatment of a range of autoimmune diseases.

In September 2011, Vertex announced results from a Phase 2a study of VX-509 that enrolled 204 people with active moderate to severe rheumatoid arthritis (RA). Based on the results, VX-509 is expected to be evaluated as part of a six-month Phase 2b study in RA.