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.