A Study to Investigate the Safety and Efficacy of Emapalumab, an Anti-IFN-gamma mAb in Patients With Systemic Juvenile Idiopathic Arthritis (sJIA) or Adult-onset Still's Disease (AOSD) Developing Macrophage Activation Syndrome/Secondary HLH (MAS/sHLH)

Emapalumab was administered at an initial dose of 6 mg/kg by intravenous infusion. Emapalumab treatment continued at a dose of 3 mg/kg, every 3 days until study day 15, and then twice-a-week for an additional 2 weeks, i.e., until study day 28. The emapalumab regimen could be adapted (the frequency between infusions shortened, the dose increased, or the treatment prolonged beyond 4 weeks) upon assessment of a favourable benefit-risk profile. There was a 4-week off-drug follow-up period (up to Week 8).