Biopharmaceutical company Swedish Orphan Biovitrum AB (Sobi) (STO: SOBI) announced on Wednesday that it will present new data on emapalumab, an anti-interferon gamma (IFNγ) antibody, targeting macrophage activation syndrome (MAS) in Still's disease patients with systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD).

Data from two studies (EMERALD; NCT05001737 and NCT03311854) involving 39 MAS patients who did not respond to high-dose glucocorticoids (GCs) showed a 53.8% complete response rate by week 8, with 85% achieving complete response at any point during the trials.

Results showed a significant reduction in glucocorticoid use, with 72% of patients tapering to ≤1 mg/kg/day by week 8. An 82.4% overall response rate was observed by week 8, with early OR seen by day 5. Clinical MAS remission was achieved by 82.1% of patients, with 94.9% survival at week 8. Safety profiles indicated no new concerns.

Emapalumab, granted FDA fast track status in May 2024, aims to address severe MAS complications in sJIA and AOSD, which can lead to organ failure and death.

Sobi plans to submit a supplemental Biologics License Application (sBLA) to the FDA in 2024.

Dr Alexei A. Grom from Cincinnati Children's Hospital will present these findings on 19 November at the ACR Convergence in Washington, D.C.