POS1190 POINTS TO CONSIDER FOR THE DIAGNOSIS AND MANAGEMENT OF CHRONIC NONBACTERIAL OSTEITIS (CNO) IN ADULTS

Background: Adults with sterile bone inflammation are variably labelled as Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis (SAPHO)-syndrome, chronic nonbacterial osteomyelitis, chronic recurrent multifocal osteomyelitis (CRMO), pustulotic arthro-osteitis, or sternocostoclavicular hyperostosis. A standardized diagnostic approach for this rare disease is lacking, and clinical management is challenging due to limited available evidence. Objectives: 1)To define overarching principles for disease definition, terminology, and clinical care of adults with sterile bone inflammation; 2)To develop points to consider (PtCs) for diagnosis and management, integrating existing evidence and multidisciplinary expert opinion. Methods: Our consensus initiative comprised a systematic literature review and appraisal of evidence, two Delphi surveys, a digital and a two-day in-person consensus meeting with an international multidisciplinary expert panel and patient representatives. Results: Three overarching principles concerning disease definition, terminology, and organization of care were defined, as well as 20 PtCs regarding diagnosis and management. Panel members and patient representatives agreed to uniformly use the diagnostic term "chronic nonbacterial osteitis (CNO)" for adults. For the initial evaluation of suspected adult CNO patients, the PtCs highlight the limited value of laboratory investigations and bone biopsies against the crucial role of imaging, which is preferably done by magnetic resonance imaging, or otherwise by computed tomography combined with nuclear imaging/bone scintigraphy. Whole-body imaging can be validly considered during initial evaluation, also in patients with clinically localized disease. Management outcomes emphasize patient-reported indices like pain since the prognostic value of persistent radiologic activity is yet unknown. A suggested treatment algorithm for adults with symptomatic CNO includes the initial use of non-steroidal anti-inflammatory drugs/cyclooxygenase 2-inhibitors in most patients, whereafter bisphosphonates or tumor necrosis factor alpha inhibitors can be considered. Typically, bisphosphonates are preferred as first-choice, though choice depends on individual patient factors and the presence of additional inflammatory features. Final PtCs concern follow-up, management of adverse events and complications, and also cover a research agenda. Conclusion: These first internal and multidisciplinary overarching principles and PtCs offer clinical guidance on the terminology, diagnosis, and management of adults with sterile bone inflammation, i.e. CNO. This consensus initiative will contribute to the timely recognition of adult CNO, improve clinical care, and facilitate future systematic and collaborative research. REFERENCES: NIL. Acknowledgements: The authors extend special thanks to physicians completing the Delphi surveys, and to the patient representatives of the Dutch CNO patient association for their contribution to this work. Disclosure of Interests: Elizabeth Winter Speaker at Amgen and UCB, Advisory board of Amgen and UCB, Olaf Dekkers: None declared, Caroline Marie Andreasen: None declared, Natasha Appelman-Dijkstra: None declared, Simone Appenzeller: None declared, Gunter Assmann: None declared, Judith Bubbear: None declared, Oana Bulaicon: None declared, Roland Chapurlat: None declared, Varvara Choida: None declared, Gavin Clunie: None declared, Salvatore D'Angelo: None declared, Dimitrios Daoussis Speaking fees from UCB, Pfizer, Novartis, BMS, MSD, Janssen, Αbbvie, Lilly and Aenorasis. Honoraria for participation in advisory boards from UCB, Pfizer, Novartis, BMS, MSD, Janssen, Αbbvie, Lilly and Aenorasis. Torsten Diekhoff Speaker for Canon MS, Novartis, MSD, UCB and Roche; Advisory board: Lilly; Grant/Support: Canon MS, ASAS, Marcel Flendrie: None declared, Olivier Fogel: None declared, Roba Ghossan: None declared, Hermann Girschick: None declared, Femke van Haalen: None declared, Neveen Hamdy: None declared, Barbara Hauser grants, personal fees and other from UCB, Kyowa Kirin, Eli Lilly, Amgen, Thornton & Ross and Gedeon-Richter and Fresenius Kabi outside the submitted work;., Christian Hedrich: None declared, Philip S Helliwell: None declared, Kay-Geert Hermann Consulting fees from AbbVie, lecture fees from MSD, Novartis, Pfizer. Co-founder of BerlinFlame GmbH. Antonella Insalaco: None declared, Anne Grethe Jurik: None declared, Mitsumasa Kishimoto received consulting fees and/or honoraria from AbbVie, Amgen, Asahi-Kasei Pharma, Ayumi Pharma, BMS, Chugai, Daiichi Sankyo, Eisai, Gilead, Janssen, Lilly, Novartis, Pfizer, Tanabe-Mitsubishi, and UCB. WIllem Lems speaking fees of Amgen, UCB, Pfuzer, Galapagos., member of advisory boards of Amgen, UCB, Pfuzer, Galapagos. Paivi Miettunen: None declared, Burkhard Muche: None declared, Ana Navas Cañete: None declared, Natalia Palmou-Fontana: None declared, Frits Smit: None declared, James Teh: None declared, Charlotte Verroken: None declared, Kurt de Vlam: None declared, Daniel Wendling speaking fees of AbbVie, BMS, MSD, Pfizer, Nordic Pharma, UCB, Novartis, Lilly, Janssen, Galapagos, Celltrion. member of advisory board of AbbVie, BMS, MSD, Pfizer, Nordic Pharma, UCB, Novartis, Lilly, Janssen, Galapagos, Celltrion., Wei Zhou: None declared, Hans-Georg Zmierczak: None declared, Anne Leerling: None declared.