Sobi® has announced that the U.S. Food and Drug Administration (FDA) has approved Gamifant® (emapalumab-lzsg) for adult and pediatric patients (newborn and older) suffering from hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) associated with Still’s disease, including systemic Juvenile Idiopathic Arthritis (sJIA). This approval specifically targets patients who have shown an inadequate response or intolerance to glucocorticoids, or who experience recurrent MAS.

This marks a significant milestone as Gamifant becomes the first FDA-approved treatment specifically for MAS in Still's disease. Sobi understands the urgency in managing MAS to improve patient outcomes, and with this approval, the company anticipates a positive impact for patients affected by MAS in Still's Disease. Gamifant is already an established therapy for primary HLH, and this expanded approval further solidifies its role in addressing critical unmet medical needs.

The FDA's decision is supported by a pooled analysis of data from two pivotal studies, the Phase 3 study (NCT05001737) and NI-0501-06 (NCT03311854). The results demonstrated compelling efficacy, with 54% of patients (21 out of 39) achieving a complete response by Week 8. Furthermore, 82% of patients (32 out of 39) achieved clinical MAS remission (VAS ≤1 cm) by Week 8. The safety and tolerability profile of Gamifant remained consistent with previous clinical studies. The most common adverse events observed in patients with HLH/MAS in Still’s disease (occurring in ≥20% of patients) included viral infections, such as cytomegalovirus infection or reactivation, and rash.

MAS in Still’s disease is a serious, potentially life-threatening complication characterized by severe hyperinflammation and potential multi-organ failure. A significant unmet medical need exists for both adult and pediatric patients with MAS. The availability of Gamifant provides a new therapeutic option to help control hyperinflammation and reduce reliance on high-dose glucocorticoids.

MAS is a severe complication of rheumatic diseases, most frequently observed in Still’s disease, which encompasses systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease. It is classified as a secondary form of hemophagocytic lymphohistiocytosis (HLH). HLH/MAS is a rare systemic disorder driven by uncontrolled interferon gamma (IFNγ) hyperinflammation, leading to symptoms such as persistent high fever, elevated ferritin, cytopenias, coagulopathies, and hepatosplenomegaly. Without effective treatment, MAS can progress to multiple organ failure and be fatal.

Gamifant (emapalumab-lzsg) is a monoclonal antibody that specifically targets and neutralizes interferon gamma (IFNγ). By blocking IFNγ, Gamifant counteracts the uncontrolled hyperinflammation characteristic of MAS. It is administered via intravenous infusion over one hour. Gamifant had previously been approved in the U.S. for the treatment of adult and pediatric patients with primary HLH who have refractory, recurrent, or progressive disease, or intolerance to conventional HLH therapy. This new approval expands its indications to address the critical needs of patients with MAS in Still's disease.

Sobi, the global biopharma company behind Gamifant, is dedicated to unlocking breakthrough innovations to transform the lives of individuals living with rare diseases.