Baricitinib, an oral selective JAK1 and JAK2 inhibitor,8 demonstrated significant clinical efficacy in phase 3 RA trials. Pooled data from these trials, including a long-term extension (LTE), inform the safety profile for baricitinib, mainly to evaluate the incidence of infection in patients with active rheumatoid arthritis (RA), with a focus on serious infection, tuberculosis (TB), herpes zoster (HZ) and opportunistic infection (OI). The data collected were from eight double-blind randomised tr...