The US Food and Drug Administration has accepted Sobi’s supplemental biologics licence application for Gamifant (emapalumab-Izsg) for haemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) associated with Still’s disease.
The application, which seeks approval for use in both adult and paediatric individuals who show an insufficient response or are not tolerant to glucocorticoids, or with recurrent MAS, has received priority review status.
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A Prescription Drug User Fee Act date was set by the agency for 27 June 2025.
The sBLA is supported by pooled data outcomes from the EMERALD and NI-0501-06 studies, which enrolled a total of 39 subjects.
53% of subjects achieved a complete response by week 8 and 85% at any time during the studies.
Sobi chief medical officer and research and development head Lydia Abad-Franch stated: “HLH/MAS in Still’s disease is a serious and potentially fatal complication where patients can experience intense hyperinflammation and even multiple organ failure.
“Gamifant (emapalumab-Izsg) selectively neutralises interferon-gamma (IFN-γ), a key driver of hyperinflammation, and if approved, may also help reduce the need for high-dose glucocorticoids in these patients.”
The therapy was previously approved by the US regulator in 2018 to treat primary HLH in adult and paediatric patients, including newborns, with refractory, recurrent or progressive conditions, or those who are not tolerant to conventional HLH therapies.
A critical complication of rheumatic conditions, HLH/MAS is most commonly observed in Still’s disease, including systemic juvenile idiopathic arthritis and adult-onset Still’s disease.
It is marked by severe inflammation, presenting with symptoms such as persistent high fever, elevated levels of ferritin, cytopenias, hepatosplenomegaly and coagulopathies.
The company received marketing authorisation from the European Commission in June 2024 for Altuvoct (efanesoctocog alfa), a treatment designed for haemophilia A patients to manage bleeds and provide perioperative prophylaxis.
