RecruitingPhase 2NCT05762640
Immune
Familial Hemophagocytic Lymphohistiocytosis
Also known as FHL, familial HLH, perforin deficiency HLH
Familial Hemophagocytic Lymphohistiocytosis is a life-threatening hyperinflammatory syndrome caused by autosomal recessive mutations in genes encoding the cytotoxic granule exocytosis pathway, leading to uncontrolled activation of macrophag
ORPHA:540 ↗Gene PRF1Gene UNC13DGene STX11Gene STXBP2Prevalence 1 in 50,000-100,000 live birthsOnset Infancy to early childhood; rarely adolescencePrimary immunodeficiency with cytotoxic lymphocyte defect
2
studies recruiting now
as of 7 Sept 2026
17
studies registered in total
as of 7 Sept 2026
3
countries with a recruiting site
as of 7 Sept 2026
9 Mar 2023
most recent study posted
among recruiting studies
Recruiting trials
RecruitingNCT01793168
Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford
Showing the 2 most recently updated recruiting studies, as recorded 7 Sept 2026. Live status on each study page.
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Countries with at least one recruiting site among the studies above, 7 Sept 2026. Tap a country to search trials there.
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About Familial Hemophagocytic Lymphohistiocytosis
Familial Hemophagocytic Lymphohistiocytosis is a life-threatening hyperinflammatory syndrome caused by autosomal recessive mutations in genes encoding the cytotoxic granule exocytosis pathway, leading to uncontrolled activation of macrophages and T cells that engulf blood cells and infiltrate vital organs. Clinical presentation is dominated by prolonged fever, cytopenias, hyperferritinemia, hypertriglyceridemia, and organomegaly, often triggered by viral infections. Without cytoreductive therapy followed by allogeneic stem cell transplantation, FHL is uniformly fatal.
Common clinical features
Prolonged high-grade fever unresponsive to antibioticsHepatosplenomegalyBicytopenia or pancytopeniaMarkedly elevated serum ferritin (often >10,000 ng/mL)Hypertriglyceridemia and hypofibrinogenemiaHemophagocytosis on bone marrow biopsyCNS involvement with irritability, seizures, or meningismus
From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.
Before you apply
Things trial teams commonly ask about for Familial Hemophagocytic Lymphohistiocytosis. Not eligibility rules; those are set by each study.
- HLH-2004 diagnostic criteria fulfillment (5 of 8 criteria) is typically required for trial entry; prepare bone marrow biopsy results, ferritin levels, NK-cell activity, and soluble CD25 data
- Emapalumab and ruxolitinib trials often require failure or intolerance of first-line dexamethasone-etoposide; document treatment history and response precisely
- Molecular confirmation of a pathogenic FHL gene variant is required for gene therapy and some transplant conditioning trials; distinguish familial from secondary HLH before applying
Related conditions
Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).