BACKGROUND Tofacitinib is an oral Janus kinase inhibitor for the treatment of ulcerative colitis (UC). We aimed to identify the safety and effectiveness of tofacitinib in patients with UC in routine clinical settings in Korea.

METHODS This open-label, observational, prospective, post-marketing surveillance study was conducted at 22 hospitals in the Republic of Korea. Patients with moderate to severe active UC who received tofacitinib were included and followed up for up to 52 weeks. Tofacitinib was administered at a dosage of 10 mg twice daily for at least 8 weeks, followed by 5 or 10 mg twice daily at the investigator's discretion based on clinical evaluation according to the approved Korean label. Safety including adverse events (AEs) and effectiveness including clinical remission, clinical response, and endoscopic mucosal healing were evaluated. Safety analysis set was defined as all patients registered for this study who received at least one dose of tofacitinib according to the approved Korean label and followed up for safety data. Effectiveness analysis set included patients in the safety analysis set who were evaluated for overall effectiveness assessment and excluded patients who had received tofacitinib less than 8 weeks.

RESULTS A total of 110 patients were enrolled, of whom 106 patients were included in the safety population. The median duration of treatment was 370 days and the treatment duration ranged from 16 to 684 days for the safety population. AEs occurred in 42 patients (39.6%). Serious AEs (SAEs) occurred in 7 patients (6.6%) and of them, there were 2 cases of serious infections. These serious infections were reported as Adverse Event of Special Interest (AESI) in this study and no other AESI were reported. There were no cases of death during the study period. Clinical remission rates were 40.0%, 46.7%, 57.6%, and 55.1% at 8, 16, 24, and 52 weeks, and clinical response rates were 77.8%, 87.9%, 56.6%, and 81.4% at each visit, respectively. Endoscopic mucosal healing rates were 58.7% at 16 weeks and 46.2% at 52 weeks.

CONCLUSION Tofacitinib was effective in Korean patients with moderate to severe active UC and the safety findings were consistent with the known safety profile of tofacitinib. This study confirmed the safety and effectiveness of tofacitinib in Korean patients with moderate to severe active UC in routine clinical settings.

TRIAL REGISTRATION This study is registered in the ClinicalTrials.gov under the identifier NCT04071405, registered on 28 August 2019.