Emapalumab as a therapeutic intervention for Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis: A case series

Abstract

Rationale: Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is characterized by a severe cytokine storm, heightened inflammatory response, and immune-mediated damage to tissues and organs. Standard treatment protocols for hemophagocytic lymphohistiocytosis often fall short in effectively controlling EBV-HLH, leading to a need for novel therapeutic options. Emapalumab, a monoclonal antibody targeting interferon-gamma, has shown promise due to its targeted cytokine modulation capabilities and favorable safety profile. This study aimed to evaluate the efficacy and safety of emapalumab in pediatric patients with EBV-HLH. Patient concerns: The case series involved 4 pediatric patients diagnosed with EBV-HLH who did not achieve disease control despite receiving comprehensive treatment. Diagnoses: All 4 pediatric patients were diagnosed with EBV-HLH. Interventions: Emapalumab was introduced as an adjunctive therapeutic intervention alongside the HLH-94 or L-DEP regimens for these patients. Outcomes: Among the 4 patients, 1 experienced severe multiorgan dysfunction and opted to discontinue therapy. The remaining 3 patients showed controlled disease progression with significant clinical improvements following emapalumab administration. These improvements included reduced levels of inflammatory markers, normalization of blood counts and liver function, and decreased Epstein-Barr virus viral load. Lessons: The findings suggest that emapalumab may be an effective and safe treatment option for pediatric EBV-HLH. However, further research is necessary to confirm these outcomes, especially in critically ill patients.