Long Term Safety Study in Patients With HLH/MAS in Still's Disease Exposed to Gamifant.

This is a prospective, low intervention, multicenter safety study to evaluate and characterize the long-term safety of Gamifant, an approved treatment for patients with HLH/MAS in known or suspected Still's disease. Pediatric and adult patients with HLH/MAS in known or suspected Still's disease, including sJIA, with inadequate response or intolerance to glucocorticoids, or with recurrent MAS, and who have either initiated Gamifant within the past 0 to 7 days or are prescribed to initiate Gamifant in accordance with the approved product label, are eligible for inclusion in the study.