Short-term, low-dose etoposide in refractory adult-onset Still's disease-associated macrophage activation syndrome.

Introduction: In this study, we modified the classical regimen of the hemophagocytic lymphohistiocytosis-04 protocol and evaluated the efficacy and safety of short-term, low-dose etoposide in patients with refractory macrophage activation syndrome (MAS) associated with adult-onset Still's disease (AOSD).

Methods: A total of 17 patients with refractory AOSD-associated MAS were enrolled and received short-term, low-dose etoposide (100 mg twice a week for four times). Another 11 patients, who were not treated with etoposide, were included as historical controls. Patient information, such as clinical manifestations, laboratory results, treatments, and short-term prognosis, were recorded and analyzed.

Results: In this case series, 88.24% of the patients with MAS who were treated with short-term, low-dose etoposide had a favorable response in 3 weeks, which was significantly higher (p = 0.017) than that in the patients with MAS who were treated without etoposide (45.45%). The 90-day survival rate after the onset of MAS was significantly higher (p = 0.0029) among the patients in the short-term etoposide group (16/17, 94.12%) than in the control group (5/11, 45.45%).

Conclusion: The regimen of short-term (2 weeks), low-dose etoposide was highly effective in the treatment for patients with refractory AOSD-associated MAS with an acceptable safety profile. Key Points • There is no high level evidence to guide the management of refractory MAS-associated AOSD patients. • This study was the first to propose and confirm the efficacy and safety of short-term, low-dose etoposide in the treatment of refractory MAS-associated AOSD patients.