Sobi's rare disease drug wins expanded FDA approval

Swedish Orphan Biovitrum AB has won expanded U.S. Food and Drug Administration approval for its drug Gamifant to treat a rare and life-threatening inflammatory complication associated with Still's disease.

The approval makes Gamifant the first treatment for adult and pediatric patients with macrophage activation syndrome, or MAS, who have not responded to or cannot tolerate glucocorticoids, the company said Friday.

MAS is a severe complication of rheumatic diseases, particularly Still's disease, and is characterized by hyperinflammation that can lead to multi-organ failure.

Gamifant, an antibody that blocks a protein called interferon gamma, was already approved in the U.S. for a related condition, primary hemophagocytic lymphohistiocytosis, or HLH.

Sobi acquired the global rights to the drug, also known as emapalumab, in 2019.

The latest approval was based on a pooled analysis of two studies in which 54% of patients achieved a complete response after eight weeks of treatment, according to the company.

“Gamifant is already an established therapy making a meaningful difference for patients with primary HLH, and with this approval, we are excited about the opportunity to positively impact patients affected by MAS in Still’s Disease,” said Guido Oelkers, Chief Executive Officer at Sobi.

The most common adverse events reported in the studies were viral infections and rash.