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

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.