Abstract Background/Aims The Paediatric Rheumatology Department at Newcastle upon Tyne Hospitals looks after children and young people (CYP) across the North East and Cumbria region. The centre treats around 220 patients (250 active prescriptions) using homecare services to deliver injectable medicines. These prescriptions are for five medicines: methotrexate, adalimumab, anakinra, tocilizumab and etanercept. This project aimed to analyse the reasons treatments were stopped and identify potentially-modifiable factors to optimise treatment. Methods Patients were identified from the departmental database. Cases were included if they stopped one of the 5 subcutaneous treatments during the period 1st July 2020 to 30th June 2021. Demographic details, the underlying diagnoses and reasons for stopping treatment were extracted from electronic patient records. Results During the 12-month period analysed, 109 prescriptions were stopped. This represented 104 unique patients (56% female). The commonest indications for treatment were juvenile idiopathic arthritis in 80% (87/109), idiopathic uveitis in 11% (12/109) and autoinflammatory diseases in 5.5% (6/109). The following treatments were stopped: methotrexate in 47 patients, adalimumab in 43, etanercept in 7, tocilizumab in 6 and anakinra in 6. The reasons for stopping prescriptions are shown in Table 1. After excluding 17 cases whose prescriptions were taken over by another unit, 92 prescriptions were stopped for clinical reasons. Of these, 28% were stopped due to side effects. All 19 patients who suffered nausea or vomiting, and all 5 patients with abnormal liver function tests, were receiving methotrexate. The 2 patients who stopped treatment due to neutropenia were both receiving tocilizumab. Almost 23% (21/92) of prescriptions were stopped due to inefficacy. All cases were switched to another biologic drug. Conclusion A substantial proportion of subcutaneous disease-modifying treatments were stopped due to inefficacy or side effects. Stopping and switching treatments represents a period of uncertainty for CYP and their families, with potential impact on disease control and quality of life. Management could be improved by a stratified medicine approach, using biomarkers to predict patients at highest risk of side effects or most likely to respond to a particular treatment. This is a key aim of current research. Disclosure K. Hartley: None. E.S. Sen: None.