Vertex Announces Oral Selective JAK3 Inhibitor VX-509 Shows Statistically Significant Improvement in RA Phase 2b Study

Vertex Pharmaceuticals

today announced 12-week results from an ongoing Phase 2b study of VX-509, an investigational oral, selective Janus kinase 3 (JAK3) inhibitor, dosed once or twice daily in people with active rheumatoid arthritis (RA) taking methotrexate. The study met its primary endpoints of both the proportion of people who achieved at least a 20 percent improvement in signs and symptoms of RA, as measured by the ACR improvement criteria (ACR20), and the change from baseline in Disease Activity Score for 28 joints (DAS28). All doses of VX-509 showed statistically significant ACR20 and ACR50 responses versus placebo and statistically significant improvement from baseline in DAS28 versus placebo. The three highest dose groups showed