Successful use of short-term add-on tocilizumab for refractory adult-onset still's disease with macrophage activation syndrome despite treatment with high-dose glucocorticoids, cyclosporine, and etoposide.

Macrophage activation syndrome (MAS) is a form of secondary hemophagocytic lymphohistiocytosis (HLH) and is a life-threatening complication of adult-onset Still disease. MAS has been usually treated with high-dose glucocorticoid with additional immunosuppressive agents, such as cyclosporine. Etoposide has been used for the treatment of severe refractory MAS based on the successful results of HLH-2004 protocol in patients with mostly primary form of HLH. We herein describe a case of severe refractory MAS secondary to adult-onset Still disease in an elderly woman that inadequately responded to etoposide but remarkably responded to additional tocilizumab. Furthermore, short-term tocilizumab led her into remission and enabled tapering off glucocorticoids after 15 months. Tocilizumab may be effective for the treatment of refractory HLH after the failure of the etoposide-containing induction regimen.