Objective Janus kinase inhibitors (JAKi) or targeted synthetic (ts) disease-modifying antirheumatic drugs (DMARDs) effectively treat rheumatoid arthritis (RA). However, due to safety concerns, the European Medicines Agency (EMA) published risk minimisation measures limiting JAKi prescription to certain at-risk patients unless no suitable alternative is available. This analysis included patients who had started their first-ever JAKi before EMA measures were published in a large national cohort study to investigate the potential impact of these measures on JAKi prescribing and utilisation in UK.Method RA patients starting first-ever JAK inhibitor therapy in BSRBR-RA between 13-February-2017 and 31-May-2022 were included. Percentages of patients meeting EMA risk criteria were presented. For at-risk patients, previous number of distinct biological (b) DMARD classes were described. Result A total of 1341 patients were included, and 80% (N=1075) met ≥1 EMA risk criterion. Of those who met ≥1 risk criterion, 529 patients (49%) had received JAKi as their first or second b/tsDMARD class, whereas 299 (28%) had received ≥3 prior bDMARD classes.Conclusion Four-in-five RA patients commencing JAKi before the EMA advisory were considered ‘at-risk' with prescribing only advised if there was no suitable alternative. Almost a third of those patients had already received ≥3 bDMARDs classes, and alternative therapies would be very limited for them; meanwhile, suitable alternatives might have existed for the remaining proportion, especially for those who received JAKi as their first or second b/tsDMARD, and re-evaluation of the suitability of their treatment may be needed.<br/
