Efficacy and safety of ruxolitinib‐based regimen in the treatment of paediatric Epstein–Barr virus‐associated haemophagocytic lymphohistiocytosis

Ruxolitinib (RUX) has demonstrated efficacy in haemophagocytic lymphohistiocytosis (HLH) patients, but large cohort studies regarding its clinical application in children with Epstein-Barr virus-associated HLH (EBV-HLH) remain scarce. This retrospective study analysed the efficacy and safety of RUX-based regimen (n = 53) and compared it with adjusted HLH-94 chemotherapy (n = 42) in the treatment of paediatric EBV-HLH. The patients treated with the RUX-based regimen received RUX monotherapy as front-line therapy. Additional methylprednisolone and etoposide would be added in sequence if the response was unsatisfactory. At 8 weeks of therapy, the overall response rate of the RUX group was comparable to that of the traditional chemotherapy group (84.9% vs. 76.2%, p = 0.282), with a 12-month survival rate of 92.2% (95% CI: 80.6-97.0) and 87.6% (95% CI: 72.1-94.5) (p = 0.595). In the RUX group, 56.6% of patients achieved sustained remission without requiring etoposide during a median follow-up of 17.2 months. Among these patients, 93.3% had primary EBV infection. The RUX-based regimen was well-tolerated, exhibiting significantly lower incidence of myelosuppression and secondary infection than adjusted HLH-94 chemotherapy (35.8% vs. 95.2%, p < 0.001; 28.3% vs. 59.5%, p = 0.002). Overall, our preliminary results indicated that EBV-HLH children treated with the RUX-based regimen demonstrated favourable efficacy while significantly reducing treatment-related adverse events.