Emapalumab-Igsz (Gamifant) is a human monoclonal antibody directed against 
interferon-γ (IFN-γ), and the first Food and Drug Administration (FDA)-approved 
therapy for primary hemophagocytic lymphohistiocytosis (HLH). HLH is a disorder 
characterized by hypercytokinemia in the setting of unbridled immune activation, 
and emapalumab represents the first therapeutic developed to address the 
underlying pathophysiology of HLH. Emapalumab is approved for treatment of 
primary HLH that is refractory, recurrent, progressing or intolerant to current 
HLH treatments in both adult and pediatric patients. FDA approval was based on 
the results of a phase II/III clinical trial evaluating the safety and efficacy 
of emapalumab in 34 pediatric patients with primary HLH, 27 of whom were 
refractory to current therapies. Additional studies of emapalumab are currently 
ongoing in adults and other pediatric populations. Here, we will review the 
pharmacology, safety and efficacy of emapalumab for the treatment of HLH.