POS0099 EFFICACY ANALYSIS OF ROMOSOZUMAB TREATMENT FOR OSTEOPOROSIS WITH HIGH RISK OF FRACTURE, FOCUSING ON CHANGES IN BONE MINERAL DENSITY DURING THE FIRST SIX MONTHS AND THE SECOND SIX MONTHS
Authors: Y. Hirano, Y. Saito
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> In Japan, romosozumab (ROMO) was approved for clinical use in January 2019 as a treatment for osteoporosis (OP) with high risk of fracture. It is known that the effects of ROMO on bone metabolism are different between the first six months and the second six months. During the first six months, ROMO exhibits a so-called dual effect of promoting bone formation and suppressing bone resorption. However, the effect of bone formation by ROMO decreases in the second six months, and the effect of suppressing bone resorption becomes the dominant mechanism of action [1]. In our clinical experience, we sometimes feel that the effect of ROMO on increasing bone mineral density (BMD) differs between the first 6 months and the second 6 months. <h3>Objectives:</h3> The purpose of this retrospective study was to investigate the effects of ROMO on BMD in patients with OP at high risk of fracture during the first six months and the second six months, and to explore related factors. <h3>Methods:</h3> The subjects were 74 patients with osteoporosis at high risk of fracture who had completed 12 months of ROMO treatment at our department. We retrospectively investigated the following. 1) Patient background at the start of ROMO, 2) Percentage change of lumbar spine BMD (LS-BMD) and total hip BMD (TH-BMD) of all patients, 3) Classification based on BMD change (first and second halves are classified into increase and decrease separately, and divided into 4 groups: increase during both the first six months and the second six months (II group), decrease during both the first six months and the second six months (DD group), increase during the first six months and decrease during the second six months (ID group), decrease during the first six months and increase during the second six months (DI group), 4) Comparison of patient characteristics such as age, gender, body mass index (BMI), bone turnover markers [BAP, P1NP, NTX, and TRACP-5b], T-score, FRAX, glucocorticoid, OP treatment just before ROMO treatment, and history of fracture at the start of ROMO between II group and DD group regarding TH-BMD. Data were expressed as mean value [standard deviation]. For statistical analysis, Wilcoxon signed-rank test and Chi-square test were used as appropriate, and p&lt;0.05 was considered statistically significant. <h3>Results:</h3> 1) Average age: 72.8 [8.8] years, 90.5% female, BMI: 20.7 [3.1], baseline T-score of LS-BMD: -2.4 [1.5], baseline T-score of T-BMD: -2.6 [0.8], FRAX [major fracture]: 29.8 [14.8] %, 22 patients [29.7%] with concomitant glucocorticoid, 30 patients [40.5%] with rheumatoid arthritis, 24 patients [32.4%] with primary OP, 66 patients [89.2%] with a history of fragility fracture, 53 patients [71.6%] with a history of vertebral fracture. Bisphosphonate and denosumab were used in 50 patients [68.5%] and 3 patients [4.1%] just before ROMO. 2) % change of LS-BMD was +6.7 [6.9] % at 6 months and +10.9 [9.2] % at 12 months. % change of TH-BMD was +1.3 [3.4] % at 6 months and +2.5 [3.5] % at 12 months. 3) LS-BMD (n=73): 62 patients (84.9%), 1 patient (1.4%), 2 patients (2.7%) and 2 patients (2.7%) were classified in II group, DD group, ID group and DI group, respectively (Figure 1). TH-BMD (n=72): 43 patients (59.7%), 16 patients (22.2%), 6 patients (8.3%) and 7 patients (9.7%) were classified in II group, DD group, ID group and DI group, respectively (Figure 1). 4) Statistically significant differences between II group and DD group of TH-BMD were observed in baseline T-score of TH-BMD [-2.8 vs. -2.3, p&lt;0.01], baseline T-score of femoral neck BMD [-2.8 vs. -2.3, p=0.02], baseline serum NTX [17.5 vs. 13.1 nmolBCE/mmol・CRE, p&lt;0.05], and baseline TRACP-5b [388 vs. 303, mU/dL p=0.02] (Table 1). <h3>Conclusion:</h3> The effect of ROMO on BMD varied depending on the case. We observed that LS-BMD was included in II group with a high probability. On the other hand, we observed that a certain number of DD groups occurred regarding TH-BMD. The DD group of TH-BMD was characterized by comparatively high total hip BMD and decreased baseline bone resorption markers. <h3>REFERENCES:</h3> [1] Cosman et al. N Engl J Med 2016. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>