Requirement for etoposide in the treatment of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

PURPOSE: We sought to identify the clinical variables most critical to successful treatment of Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH).

PATIENTS AND METHODS: Among the factors tested were age at diagnosis (< 2 years or > or = 2 years), time from diagnosis to initiation of treatment with or without etoposide-containing regimens, timing of cyclosporin A (CSA) administration during induction therapy, and the presence or absence of etoposide.

RESULTS: By Kaplan-Meier analysis, the overall survival rate for the entire cohort of 47 patients, most of whom had moderately severe to severe disease, was 78.3% +/- 6.7% (SE) at 4 years. The probability of long-term survival was significantly higher when etoposide treatment was begun less than 4 weeks from diagnosis (90.2% +/- 6.9% v 56.5% +/- 12.6% for patients receiving this agent later or not at all; P <.01, log-rank test). Multivariate analysis with the Cox proportional hazards model demonstrated the independent prognostic significance of a short interval from EBV-HLH diagnosis to etoposide administration (relative risk of death for patients lacking this feature, 14.1; 95% confidence interval, 1.16 to 166.7; P =.04). None of the competing variables analyzed had significant predictive strength in the Cox model. However, concomitant use of CSA with etoposide in a subset of patients appears to have prevented serious complications from neutropenia during the first year of treatment.

CONCLUSION: We conclude that early administration of etoposide, preferably with CSA, is the treatment of choice for patients with EBV-HLH.