Severe Hepatitis Intervention With Emapalumab for Liver Disease

The goal of this study is to see whether a medicine called emapalumab, a monoclonal antibody, is safe and works well for patients aged 1 year and older who have indeterminate severe hepatitis with T-cell activation and have not responded well to steroids or still need them. This study has a Screening Cohort and an Intervention Cohort. The Screening Cohort will enroll patients with severe hepatitis of all etiologies to observe and collect research samples. Patients enrolled on the Screening Cohort will be asked to participate on the Intervention Cohort if they develop steroid-refractory/ dependent indeterminate severe hepatitis (iSH-T). Additionally, patients may bypass the Screening Cohort and enroll directly in the Intervention Cohort if they already meet its eligibility criteria. Patients in the Intervention Cohort will be treated with emapalumab.