Potential impact of European Medicines Agency measures to minimise risk of serious side effects on JAKi prescribing and utilisation in the UK

Abstract Objective Janus kinase inhibitors (JAKis) 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-minimization 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 utilization in the UK. Method RA patients starting first-ever JAKi therapy in BSRBR-RA between 13 February 2017 and 31 May 2022 were included. The percentages of patients meeting the EMA risk criteria were presented. For the at-risk patients, their previous numbers of distinct biologic (b) DMARD classes prescribed 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-fifths of RA patients who had commenced a 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; however, suitable alternatives might have existed for the remaining proportion, especially for those who received a JAKi as their first or second b/tsDMARD, and re-evaluation of the suitability of their treatment may be needed.