Emapalumab Use in Patients With Rheumatologic Disease–Associated Hemophagocytic Lymphohistiocytosis in the United States: the REAL‐HLH Study

Rheumatologic disease-associated hemophagocytic lymphohistiocytosis (HLH), a rare, life-threatening, systemic hyperinflammatory syndrome, occurs as a complication of underlying rheumatologic disease. Real-world evidence is lacking on emapalumab, a fully human monoclonal antibody that neutralizes the proinflammatory cytokine interferon-γ, approved for treating patients with primary HLH.