LAUSR

Tofacitinib is an oral, small-molecule Janus kinase inhibitor approved in South Korea for the treatment of moderate to severe ulcerative colitis (UC) on May 1, 2019. However, safety data are lacking. We investigated the incidence of serious adverse events (SAEs) in patients with UC using tofacitinib from the National Health Insurance Service database. In all, 1,026 UC patients were enrolled in this study. The overall incidences (100 person-years; 95% confidence interval) of SAEs were 4.06 (1.63–8.36) and 6.30 (4.59–8.43) in the tofacitinib and anti-TNFi groups, respectively. No thromboembolic event occurred and major cardiovascular events occurred in only three patients (two unstable angina and one congestive heart failure) in the tofacitinib group. The incidence of herpes zoster and tuberculosis did not differ between the two groups. There was no difference in the overall incidence of SAEs, including thromboembolic events, between tofacitinib- and TNFi-treated UC patients.