Ahmed A, Merrill SA, Alsawah F, et al. - Among adults (aged 18 years or more) with secondary haemophagocytic lymphohistiocytosis, researchers evaluated the safety as well as the activity of a JAK inhibitor, ruxolitinib, at the University of Michigan Rogel Cancer Center (Ann Arbor, MI, USA). Participants were 5 patients in total who were administered oral ruxolitinib (15 mg twice a day) on a continuous 28-day cycle, or until disease progression or unacceptable toxicity. Findings revealed no deaths over a median follow-up of 490 days. The estimated 2-month overall survival was 100%. All participants showed symptom resolution (either partial or complete) and disease-related laboratory abnormalities. Within the first week of therapy, improvement in cytopenias was evident in all patients. Grade 4 febrile neutropenia was the single serious adverse event documented. This treatment led to improvements in inflammatory markers (eg, ferritin, soluble IL-2 receptor) and T cells and monocytes activation (ie, reduced STAT1 phosphorylation). As per these preliminary data, the activity of ruxolitinib, as well as its good tolerability and manageable profile in the outpatient setting was evident among patients with secondary haemophagocytic lymphohistiocytosis.