P044 Janus Kinase Inhibitors-a retrospective study on side effects and discontinuation reasons

Abstract Background/Aims In light of drug safety warnings for Janus kinase inhibitors (JAKi), we aimed to evaluate the occurrence of adverse events and identify reasons for discontinuation of JAKi in clinical practice. Methods Medical records of all patients prescribed JAKi in NHS Grampian from January 2021 to January 2023 for rheumatic diseases were retrospectively reviewed. Patient demographics, co-morbidities, reasons for treatment discontinuation and occurrence of adverse events (including cardiovascular events) were recorded. Results 160 patients were prescribed JAKi. 131 (81.8%) patients had rheumatoid arthritis, 16 (10%) psoriatic arthritis, five (3%) axial spondyloarthritis, three (2%) juvenile idiopathic arthritis (in adulthood), 3 (2%) undifferentiated inflammatory arthritis, one (0.6%) granulomatous polyangiitis (GPA), one (0.6%) enteropathic arthritis. Mean duration of treatment was 9.9±12 months with 34.4% on treatment for >12 months. 47.5% discontinued JAKi after an average of 7.0 ± 5.1 months. Patients discontinuing treatment were significantly older than patients who continued treatment 60.1yrs ± 11.0 vs 55.9yrs ± 12.5 respectively, p = 0.03. There were no differences between discontinuing and continuing treatment groups with respect to BMI, smoking, diabetes, cardiovascular disease, hypertension or statin use. Discontinuation rates were 66.7 % tofacitinib, 44.4 % filgotinib and 34.4 % upadacitinib. Discontinuation reasons were inefficacy (37.9 %), headache (9.2 %), infections (9.2 %) and gastrointestinal adverse effects (8.0 %). One patient discontinued JAKi due to an arterial embolism (DVT in the context of undiagnosed patent foramen ovale), three developed new onset hypertension. Common infections leading to discontinuation were urinary tract (37.5 %) and chest (25.0 %), with one case of tuberculosis. No herpes zoster infections led to JAKi discontinuation. In patients who continued treatment infections occurred in 27.1% (30% chest, 21.7%, Covid-19, 13% UTIs, 8.7% herpes zoster 8.7% otitis media). Other adverse events such as fatigue and nausea were reported in < 4 % of all patients. No malignancies were recorded. Conclusion Older patients are more likely to discontinue JAKi due to infections. Upadacitinib patients were least likely to discontinue. Treatment inefficacy, urine and chest infections were the commonest reasons for discontinuation. Disclosure J. Klein: None. J. Alexander: None. L. Robertson: Other; LR has received funding for conference attendance from UCB. R. Hollick: None.