PO:20:006 | Efficacy of denosumab in glucocorticoid-induced osteoporosis patients with prior exposure to intravenous aminobisphosphonates

Kiren Khalid¹, Alessandro Giollo¹, Mariangela Salvato¹, Francesca Frizzera¹, Lorenzo Di Luozzo¹, Bernd Raffeiner², Andrea Doria¹ | ¹Rheumatology Unit, Department of Medicine - DIMED, University of Padova, Padova, Italy; ²Department of Rheumatology, Bolzano Central Hospital, Bolzano, Italy

Background. Data on the efficacy of denosumab (DMAB) in patients exposed to potent intravenous aminobisphosphonates (NBPs) are lacking, especially in those with glucocorticoid-induced osteoporosis (GIOP). The aim of this study was to compare the increase in bone mineral density (BMD) in patients with GIOP treated with denosumab (DMAB), according to the previous exposure to potent NBPs (zoledronate, neridronate).

Materials and Methods. In this retrospective cohort study, we included female, post-menopausal patients with rheumatic musculoskeletal diseases (RMDs) who initiated treatment with denosumab 60 mg every 6 months for GIOP between 06/2019 and 06/2023 in a single tertiary centre; patients underwent dual energy X-ray absorptiometry (DEXA) before starting treatment and after 24 months. We compared changes from baseline to follow-up of the T-score at the lumbar spine, femoral neck and total hip in patients who were DMAB/NBPs-experienced to those who were DMAB/NBPs-naive, adjusting for the cumulative prednisone dose.

Results. Thirty-two patients with GIOP who initiated DMAB during the study period and had follow-up data were included (mean (SD) age 72 (12) years, FRAX 34 (22) %, 19/32 (59%) with prior fractures). The main RMD diagnoses were inflammatory arthritis (n=17, 53%) and CTD (n=15, 42%). There were no significant differences at baseline between DMAB/NBPs-experienced compared to DMAB/NBPs-naive patients, including the prevalence of CKD stage 3/4/5. In the DMAB/NBPs-experienced group, the median exposure to NBPs was 19 months. Mean (SD) T-scores at any site significantly increased at follow-up (+0.8 (0.7), +0.4 (0.6), +0.3 (0.6) for lumbar spine, femoral neck and total hip respectively; p<0.005 for all), without differences between treatment groups (Figure 1). During the study period, three new fractures occurred, two in the DMAB/NBPs-experienced group and one in the DMAB/NBPs-naive group. Bone turnover markers decreased with a similar magnitude between groups (mean (SD) CTX % change, DMAB/NBPs-naive vs. DMAB/NBPs-experienced: -48 (37) % vs. -61 (30) %, p=0.245; P1NP: -40 (10) % vs. -38 (21) %, p=0.691).

Conclusions. This small real-life study cohort of patients with GIOP provides evidence that DMAB is effective in increasing BMD, irrespective of prior use of potent intravenous NBPs.