TNF-inhibitors or bisphosphonates in chronic nonbacterial osteomyelitis? - Results of an international retrospective multicenter study

Chronic nonbacterial osteomyelitis (CNO) can cause significant morbidity, including bone pain and damage. In the absence of clinical trials, treatments include non-steroidal anti-inflammatory drugs, corticosteroids, TNF-inhibitors (TNFi) and/or bisphosphonates. In a retrospective chart review in the United Kingdom and Germany, we investigated response to TNFi and/or pamidronate. Ninety-one patients were included, receiving pamidronate (n = 47), TNFi (n = 22) or both sequentially (n = 22). Patients with fatigue [p = 0.003] and/or arthritis [p = 0.002] were more frequently treated with TNFi than pamidronate. Both therapies were associated with clinical remission at 6 months, and reduction of bone lesions on MRI at 12 months. While not reaching statistical significance, pamidronate resulted in faster resolution of MRI lesions. Fewer flares were observed with TNFi. Failure to respond to pamidronate was associated with female sex [p = 0.027], more lesions on MRI [p = 0.01] and higher CRP levels [p = 0.03]. Randomized clinical trials are needed to confirm observations and generate evidence. •In the absence of clinical trials, treatment of CNO is empiric.•TNF inhibitors and pamidronate are effective in CNO.•Pamidronate induces remission more rapidly, TNF inhibitors are associated with fewer flares.•Failure to respond to pamidronate is associated with female sex, high numbers of bone lesions, and elevated CRP.•Observations argue for the use of TNF inhibitors and/or pamidronate in CNO.