SAT0261 Different Treatment Strategies for Chronic Non-Bacterial Osteomyelitis: The Experince of 52 Patients

Background Chronic non-bacterial osteomyelitis (CNO) is a heterogenous group of immune-mediated inflammatory bone diseases, often co-exist with other rheumatic diseases. There are no approved treatments for CNO except non-steroid anti-inflammatory drugs (NSAID). The efficacies of methotrexate (MTX), sulfasalazine, pamidronate (PAM), anti-IL1 and TNFα-inhibitors (TNFα-inh) were shown in different reports. Objectives The aim of study: to compare the efficacy of non-randomized different treatment approaches in pediatric patient CNO cohort. Methods 52 children (25 M and 27 F) with CNO has average age at the onset of disease 8.4 years (5.4÷11.0), the number of foci - 3.0 (2.0÷6.0, incl. multifocal cases in 80.8%), fever at the onset – 38.5%, spine involvement - 34.6%, positive family autoimmune diseases (AID) history - 7.7%, concomitant AID - 67.3%. NSAID was the first-line treatment for non-vertebral cases, as well as PAM for vertebral involvement. Second-line treatment includes MTX, PAM and TNFα-inh. Dynamics of pain, patient9s (PVAS) and physician9s (MDVAS) assessment and ability to each medication to achieve remission of CNO activity we evaluated. Results According to the NSAID, MTX, SSZ, PAM and TNFα-inh groups next data were registered: PVAS: -14.2% (p=0.05), -50.0% (p=0.04), -23.1 (p=0.89), -83.3% (p=0.0001), -73.6% (p=0.0007); pain: -21.9% (p=0.01), -18.6% (p=0.13), +36,4 (p=0.89), -79.7% (p=0.00016), -74.1%, (p=0.0015); MDVAS: -13.8% (p=0.13); -56.4% (p=0.09), +30.8% (p=0.89), -74.7%, (p=0.0001), -82.1 (p=0.0015) respectively. The ability of each treatment strategy to achieve the CNO remission was 52.6%, 44.4%, 57,1%, 88.8% and 73.3% respectively (log-rank test, p=0,001, figure). TNFα-inh usually used as second-third line treatment in cases where other options, especially PAM were fall. Conclusions The most effective treatment approaches for CNO were PAM and TNFα-inh. The randomized controlled trials for assessment efficacy and safety of these medications is mandatory to confirm these results. Disclosure of Interest None declared