Ruxolitinib-based regimen in children with autoimmune disease or autoinflammatory disease-related haemophagocytic lymphohistiocytosis.

For autoimmune disease (AD) and autoinflammatory disease (AID)-related haemophagocytic lymphohistiocytosis (HLH) (AD/AID-HLH), there is still a lack of standardized treatment. Glucocorticoids (GCs) are the main treatment currently; however, 37.9% to 61% of patients fail to achieve effective control of HLH, making it urgent to find novel treatment strategies. We conducted a retrospective, single-centre study examining ruxolitinib (RUX)-based regimen in children with AD/AID-HLH. Patients were first treated with RUX monotherapy, and additional treatments including methylprednisolone and etoposide were added sequentially when the disease could not be controlled. The study included 26 patients with a median follow-up of 23.9 months, of whom 15 had prior treatments. The overall response rate at week 8 with the RUX-based regimen was 96.2%, with 92.3% attaining complete response (CR) and 3.9% attaining partial response. The 2-year overall survival rate was 96.2% (95% CI, 80.4% to 99.9%). During RUX monotherapy, 46.1% of patients achieved CR as the best response, with a median first response time to RUX of 2 days. Additionally, 53.8% of patients required additional GCs and 23.1% required etoposide chemotherapy. All observed adverse events were manageable and acceptable. Overall, our study supports the efficacy and safety of the RUX-based regimen in children with AD/AID-HLH.