Sobi North America, the North American affiliate of Sobi, today announced that the US Food and Drug Administration (FDA) has granted Fast Track designation to emapalumab-lzsg being investigated as a potential therapeutic option in patients with Macrophage Activation Syndrome (MAS). Emapalumab is a fully human, anti-IFNγ monoclonal antibody that binds free and receptor-bound IFNγ, neutralizing its biological activity. Emapalumab is currently in Phase lll development for MAS.

Fast track designation is designed to facilitate the development and expedite the review of medicines to treat serious conditions that may fill an unmet medical need.

MAS is a severe complication of rheumatic diseases, most frequently in Still’s disease including systemic juvenile idiopathic arthritis (sJIA). Interferon gamma (INFy) is a key cytokine in the development of MAS. MAS is classified as a form of haemophagocytic lymphohistiocytosis (HLH) and characterized by fever, hepatosplenomegaly, liver dysfunction, cytopenias, coagulation abnormalities and hyperferritinaemia, possibly rapidly progressing to multiple organ failure and death.

Emapalumab-lzsg is the first and only medicine approved in the US for primary HLH, a rare syndrome of hyperinflammation that can rapidly become fatal unless diagnosed and treated.