FRI0493 CLINICLAL EFFICACY OF DENOSUMAB IN PATIENTS WITH OSTEOPOROSIS BETWEEN RHEUMATOID ARTHRITIS AND PRIMARY OSTEOPOROSIS; 24 MONTHS OF FOLLOW-UP
Authors: Yasuhide Kanayama, Taichi Tsuji, Naohisa Futamura, Naoaki Osada, Hiroto Tachi, Kazunori Todoroki, Ryosuke Sugimoto
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Denosumab (DMB) is a fully human monoclonal antibody to the receptor activator of nuclear factor-kappaB ligand (RANKL) that blocks its binding RANK, inhibiting the development and activity of osteoclasts, decreasing bone resorption, increasing bone density and reducing fracture risk. Also DMB is a useful therapeutic agent for both rheumatoid arthritis (RA-OP) and primary osteoporosis (P-OP). However there is still few comparative study of clinical efficacy of DMB between RA-OP and P-OP. <h3>Objectives</h3> To compare the clinical efficacy of DMB in patients with osteoporosis between rheumatoid arthritis and primary osteoporosis for 24 months. <h3>Methods</h3> RA patients diagnosed according to the 2010 ACR/EULAR criteria. RA-OP and P-OP patients met at least one of the following criteria were eligible; a bone mineral density T score of -2,5 or less at the lumber spine or total hip and either one or more moderate or severe vertebral fractures or two or more mild vertebral fractures. All patients were initiated DMB from between October, 2013 and August, 2016. The final study cohort of 61 RA- OP and 50 P-OP patients received continuous DMB therapy more than 24 months. The DMB dose was 60mg at once every 6 months. In all cases native or activated vitamin D has been used. We reviewed the results for 24 months about the increase and decrease of bone mineral density(BMD) of lumbar spine(LS) and total hip(TH) by DEXA and bone turnover markers, intact n-terminal propeptide type I procollagen(PINP) and tartrate-resistant acid phopshatate form 5b(TRACP-5b). <h3>Results</h3> In the patients of RA-OP (n=61) and P-OP (n=50), the number of female was each 56(92%) and 45(90%) cases(p=0.741). The mean age was 72.7 ± 7.5 and 76.8 ± 7.8 years old (p=0.006); disease duration of RA-OP patients was 12.6 ± 12.9 years; the body mass index was 20.4 ± 2.7 and 20.3± 3.0 (p=0.687) and the FRAX was 27.2 ± 15.7 and 24.6 ± 11.1 (p=0.745). Clinical findings related to RA-OP at baseline were as follows; CRP 0.8 ± 1.1; DAS-CRP 3.28 ± 1.36; HAQ 1.16 ± 1.04 in RA-OP patients and in the patients of RA-OP and P-OP, bone turnover markers and bone mineral density at baseline were as follows; P1NP 57.7 ± 32.2 and 64.0 ± 32.7 μg/l(p=0.151); TRACP-5b 563 ± 237 and 570 ± 217 mU/dL (p=0.674); LS-BMD 0.85 ± 0.16 and 0.74 ± 0.13 g/cm<sup>2</sup>(p&lt;0.001) and TH-BMD 0.62 ± 0.09 and 0.60 ± 0.08 g/cm<sup>2</sup> (p=0.110). The rate of decreased P1NP from baseline to 6, 12 and 24 months were each -43.7% vs -61.3% (p=0.015) at 6 month, -40.2% vs -55.2% (p&lt;0.001) at 12 month and -43.5% vs -67.9% (p&lt;0.001) at 24 month and TRAC-5b were -44.6% vs -51.5% (p=0.225) at 6 month, -39.5% vs -53.0% (p=0.007) at 12 month and -41.3% vs -54.2% (p=0.663) at 24 month in the RA-OP vs P-OP group. The rate of increased LS-BMD from baseline to 6, 12 and 24 months were each 4.3% vs 4.5% (p=0.743) at 6 month, 6.3% vs 6.9% (p=0.575) at 12 month and 9.3% vs 11.1% (p=0.300) at 24 month and TH-BMD were 2.5% vs 2.6% (p=0.583) at 6 month, 3.3% vs 3.2% (p=0.683) at 12 month and 5.7% vs 4.2% (p=0.403) at 24 month RA-OP vs P-OP group. <h3>Conclusion</h3> DMB was effective for both RA-OP and P-OP, and the clinical efficacy was almost similar between the two groups. <h3>Disclosure of Interests</h3> None declared