FDA Approves Sobi’s Gamifant Application for HLH/MAS Treatment

The US Food and Drug Administration (FDA) has accepted a supplemental biologics license application for Gamifant (emapalumab-Izsg), submitted by Swedish Orphan Biovitrum AB (Sobi), to treat haemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS) associated with Still’s disease. This treatment is proposed for both adults and children who have not responded adequately to glucocorticoids, cannot tolerate them, or have recurrent MAS. The application has been granted priority review status by the FDA, with a decision deadline set for June 27, 2025, under the Prescription Drug User Fee Act.

Gamifant acts by selectively neutralizing interferon-gamma (IFN-γ), a critical factor in the inflammatory process associated with these conditions. If approved, this therapy could potentially lessen the dependency on high-dose glucocorticoids, offering a significant advance in the management of this serious and potentially life-threatening complication. HLH/MAS, characterized by intense hyperinflammation, is most frequently observed in individuals with Still's disease. Symptoms of this condition include persistent high fever, elevated ferritin levels, cytopenias, hepatosplenomegaly, and coagulopathies, leading to possible multiple organ failure.

The submission to the FDA is backed by data derived from two studies—EMERALD and NI-0501-06—which collectively enrolled 39 patients. Results from these studies indicated that a complete response was achieved by 53% of participants by the eighth week, with 85% responding at some point during the trials. These promising outcomes support Gamifant's potential as a therapeutic option for managing HLH/MAS within the context of Still's disease.

Dr. Lydia Abad-Franch, Sobi's Chief Medical Officer and Head of Research and Development, emphasized the significance of this application, noting the severity of HLH/MAS in Still's disease patients. She highlighted the promising role of Gamifant in neutralizing IFN-γ, a key player in disease progression and symptom manifestation, and its potential to reduce the necessity for high-dose steroid treatments.

Previously, in 2018, Gamifant received FDA approval for treating primary HLH in both adults and children, including newborns, who suffer from refractory, recurrent, or progressive disease or those intolerant to standard therapies. This prior approval underscores the drug's established therapeutic profile and its applicability to a wider patient demographic experiencing severe inflammatory conditions.

In addition to this FDA application, Sobi also received marketing authorization from the European Commission for Altuvoct (efanesoctocog alfa) in June 2024. This medication is intended for patients with haemophilia A, designed to manage bleeding episodes and provide perioperative prophylaxis. This latest development in Sobi's portfolio underlines the company's ongoing commitment to addressing complex and rare medical conditions through innovative therapeutic solutions.