Swedish biopharmaceutical company Sobi (STO:SOBI) announced on Saturday that the US Food and Drug Administration (FDA) has approved Gamifant (emapalumab-lzsg) for the treatment of adult and paediatric (newborn and older) patients with haemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) in known or suspected Still's disease, including systemic Juvenile Idiopathic Arthritis (sJIA), with an inadequate response or intolerance to glucocorticoids, or with recurrent MAS.

This approval is based on results of the pooled data from two pivotal studies, the Phase 3 study and NI-0501-06. Results showed that 54% (21/39) of patients had a complete response at Week 8, and 82% (32/39) achieved clinical MAS remission (VAS less than 1 cm) at Week 8. Safety and tolerability were consistent with previous clinical studies. In patients with HLH/MAS in Still's disease, the most common adverse events (greater than 20%) were viral infections, including cytomegalovirus infection or reactivation, and rash.

Gamifant, an interferon gamma (IFN gamma)-blocking antibody, is claimed to be the first and only FDA approved treatment for adult and paediatric (newborn and older) patients with primary HLH with refractory, recurrent or progressive disease or intolerance with conventional HLH therapy.

Gamifant is also approved in the United States for the treatment of adult and paediatric (newborn and older) patients with primary haemophagocytic lymphohistiocytosis (HLH) with refractory, recurrent or progressive disease or intolerance with conventional HLH therapy.