SAT0408 Safety of concomitant treatment with denosumab and other biological drugs
Authors: M. Garijo Bufort, M. Guerra González, C. Moriano Morales, C. Iñiguez Ubiaga, A. Crespo Golmar, I. González Fernández, A. López Robles, E. Diez Álvarez, C. Álvarez Castro, M. Martin Martínez, M.E. Vallejo Pascual, T. Pérez Sandoval
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Denosumab (DB) is a monoclonal antibody to RANK ligand that, like all biological drugs, can be associated with an increased risk of infections. However, there are few studies concerning the risk of infection in these patients treated concomitantly with DB and other biologic drugs. <h3>Objectives</h3> This study aims at determining whether the treatment with biological drugs and DB combined is associated with an increased risk of adverse effects in patients with autoimmune diseases. <h3>Methods</h3> Retrospective observational study of patients treated with DB combined with other biological drugs at the Hospital of León between 2010–2017. For proper patient selection, the data obtained from the medical prescription program of primary care and the data from the registry of outpatients and walk-in patients of hospital pharmacy were cross-referenced. To determine the increased risk, a control group of patients treated both with bisphosphonates (BF) and with biological agents was selected. The data collected in both groups were: age, sex, diagnosis, comorbidities and other prescribed drugs. Infection, tumour or other adverse effects appeared three months, six months, one year and two years after starting the concomitant treatment. When performing the statistical analysis, it was analysed the time elapsed until the first adverse effect appeared. <h3>Results</h3> A total n of 28 patients was registered. 16 were treated with BF and biological agents, and 12 were treated with DB and other biological drugs. The prevalence of women was higher in both groups (87.5% BF, 91.7% DB). The mean age at the beginning of the concomitant treatment was similar, being 69.1±8.5 years in the BF group and 69.7±7.1 years in the DB group. All patients treated with DB were diagnosed with RA. Regarding the comorbidities, it seems that those patients treated with DB had fewer CVRF than those treated with BF (68.8% HBP in BF versus 50% in DB, 37.5% dyslipidaemia in BF versus 33.3% in DB). The biological drugs prescribed to be used concomitantly with DB were: 49.7%anti-TNFα, 33.3%rituximab, 8.3%abatacept and 8.3%tocilizumab. In addition, there were no significant differences regarding the application time of the concomitant treatment with biological agents in the BF (35.7±26.7 months) and DB (58.6±43.7 months) groups; being in both groups similar. By comparing both groups, it is observed that those patients treated concomitantly with DB and other biological drugs, have more infections and these appear earlier in time than in patients treated with BF and biological agents (p&lt;0.005). Only one patient in the DB group had a tumour of pulmonary nature as an adverse effect. There were no differences in the appearance of adverse effects in patients with other comorbidities or concomitant treatments. <h3>Conclusions</h3> It seems that the treatment of DB combined with other biological drugs is associated with a greater number of adverse effects, mainly caused by infections, and having an earlier appearance. More studies and a larger sample would be necessary to confirm this association and to be able to prove the relationship between comorbidities and the use of other concomitant drugs with the appearance of adverse effects. <h3>Disclosure of Interest</h3> None declared