Real-World Effectiveness of Upadacitinib for Treatment of Rheumatoid Arthritis in Canadian Patients: Interim Results from the Prospective Observational CLOSE-UP Study

Upadacitinib (UPA), a selective, reversible, oral Janus kinase (JAK)-1 inhibitor, was approved in 2019 in Canada for the treatment of adults with moderately to severely active rheumatoid arthritis (RA). This phase 4 prospective study aimed to characterise the effectiveness of UPA in the real-world population of patients with RA. Adults with RA who initiated treatment with once daily UPA (15 mg) and enrolled in the Canadian Real-Life post-marketing Observational Study assessing the Effectiveness of UPadacitinib for treating rheumatoid arthritis (CLOSE-UP) and who completed a 6-month assessment as of 28 February 2023 were included. The primary endpoint of the CLOSE-UP study is the proportion of patients achieving a Disease Activity Score-28 Joint Count C-reactive protein (DAS28-CRP) < 2.6 at 6 months. Data was collected at routine visits. Data analysed and summarised descriptively for the overall interim population and for subgroups based on prior therapy included remission or low disease activity, patient-reported outcomes (PROs), and adverse events. A total of 392 patients were included in the interim analysis. Overall, 63.5% (191/301) of patients achieved a DAS28-CRP score < 2.6 at month 6, with similar rates observed for all subgroups analysed according to prior therapy including those with prior JAK inhibitor exposure (range 57.4–71.0%), and in patients who received UPA monotherapy (71.6% [48/67]). Early (month 3) and sustained improvements up to 6 months were observed for all PROs. The safety profile was consistent with previous reports. Real-world improvements in disease activity and PROs in response to UPA treatment were consistent with clinical trial data across a range of Canadian patients with prior therapy exposure and with UPA monotherapy, with an overall favourable benefit–risk profile. NCT04574492.