Tofacitinib in chronic non-bacterial osteitis: a potential therapeutic option for multifocal osteitis.

Chronic non-bacterial osteitis (CNO) is an autoinflammatory bone disorder with an evolving classification and limited treatment options. It encompasses conditions like SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis) syndrome and chronic recurrent multifocal osteomyelitis, which share overlapping clinical and radiological features. While nonsteroidal anti-inflammatory drugs (NSAIDs) serve as first-line therapy, refractory cases require second-line options such as tumor necrosis factor (TNF) inhibitors or bisphosphonates. Emerging evidence suggests Janus kinase inhibitors (JAKis), including tofacitinib, as a viable third-line alternative, though data remains limited. We describe a 16-year-old adolescent male presenting with multifocal osteitis and acneiform lesions, initially classified as SAPHO syndrome but later redefined as CNO based on "2024 recommendations published in Annals of the Rheumatic Diseases." The patient had an inadequate response to NSAIDs, and financial constraints precluded the use of TNF inhibitors or bisphosphonates. Tofacitinib (5 mg twice daily) was introduced as a third-line therapy. Within 8 weeks, the patient showed significant symptom resolution, and magnetic resonance imaging confirmed a reduction in STIR (Short-Tau Inversion Recovery) hyperintense signals. By 6 months, there was complete clinical and radiological remission. This case underscores the reclassification of SAPHO within the broader CNO spectrum and highlights the potential role of tofacitinib as a third-line treatment for refractory CNO. The rapid and sustained response observed suggests that JAKis could be considered in select cases where second-line options are inaccessible. Further research is warranted to establish optimal treatment strategies for this complex condition.