AB1267 LONG-TERM SINGLE CENTER EXPERIENCE OF THE THERAPY WITH BIOLOGICS IN MULTIFOCAL NON-BACTERIAL OSTEOMYELITIS

BackgroundChildren and adolescents who suffered from the rare polygenic autoinflammatory disease such as multifocal non-bacterial osteomyelitis (NBO) can stay without specialized care for the long time. Currently we don’t have standardized treatment for these patients. Administration of Biologics (B) established on opportunity to diagnose juvenile idiopathic arthritis (JIA) or juvenile ankylosing spondylitis (JAS) in relation to combination of bone lesions with arthritis and/or axial skeleton damage.ObjectivesTo describe clinical/laboratory findings and therapy approaches in patients with NBO who was treated by BA.MethodsWe analyzed a single center retrospective nine-year study, which includes cohort of 56 patients (pts) with multifocal NBO. 22 pts of them were treated by different B (TNF-inhibitors mostly) in our pediatric department. Standard rheumatological assessment were included for all pts. X-ray, whole-body MRI and/or scintigraphy were done for revealing all localizations of bone lesion. Infection, oncology and other reasons of bone damage were excluded at the time of B administration.ResultsIn total we identified 22 pts (10-boys; 12-girls) treated by B (TNF-inhibitors as first-line) among the whole group (n=56). The median age at the disease onset was 10 years (Me 10, range 1.3;16,5). Classifying diagnosis according to rheumatological nosology as JIA or JAS we were able for legal administration of targeted agents. 12 pts had JIA (7 girls), 10 pts had JAS (5 girls). JIA was presented by poly- (7 pts) and oligoarticular (5 pts) types. MRI evidence of axial involvement that was established on active erosive sacroiliitis with deep bone marrow edema had 15 pts (68%), on active spondylitis in thoracic spine – 3 pts, on erosive arthritis with partial ankyloses of facet joints of neck – 3 pts; multiple syndesmophytes had 1 girl. According to our findings, axial damage associated with NBO had developed much earlier (at 2 y.o. as minimum) than in case of «idiopathic» JAS. HLA-B27 positive was 11 pts, high levels of ANA had 5 pts (all of them HLA-B27 negative). Extraskeletal manifestations were observed in 8 pts (acne conglobate, uveitis, inflammatory bowel disease – one in each condition, psoriasis pustulosus – 5). High laboratory markers were revealed before biologics in 14 pts. Non-biological therapy was based on worldwide practice and included NSAIDs (all pts), methotrexate (10 pts), sulfasalazine (10 pts, in 9 pts it was withdrawal), bisphosphonates (2 pts), glucocorticoids (7 pts). Persistent arthritis, severe course of NBO, appearance of new bone lesions, refractory to treatment were determinant factors for administrate the TNF-inhibitors. Among first line of B etanercept (ETN) was used in 14 pts (63%), adalimumab (ADA) – in 5 pts (23%), golimumab – in 2 pts (9%), infliximab (IFX) – in 1 pts (4,5%). At the start of B the average age was 13.7 years (range 7.2-17.9); mean disease duration was 3,4 years (range 0.3-8.1). There were 4 cases of withdrawals: 1 for IFX (to ETN) due to development of skin involvement (chalazion,streptoderma), 3 for ETN. In 2 pts due to inefficacy ETN was switched to ADA. Decreasing of disease activity was detected in the most of patients. Among them 2 pts developed the whole remission with resolving of active arthritis and bone marrow edema spots. Skin lesions (acne, psoriasis) were significantly improved. There weren’t fixed adverse events during TNF-therapy except of the development of staphylococcus sepsis under ETN in a patient with rare genetic comorbidity (congenital indifference to pain). ETN was withdrawn immediately. The patient was treated for a long time by the surgery methods and antibiotics. A year later because of flares of arthritis JAK-inhibitors tofacitinib was administrated and marked improvement achieved.ConclusionEstablished on our experience, we can suggest that treatment with TNF-inhibitors is a good therapy approach for patients with high activity of NBO. It’s expected that option of prescribing BA can prevent progression and bone destruction.Disclosure of InterestsNone declared