Emapalumab

Emapalumab, sold under the brand name Gamifant, is an anti-interferon-gamma (IFNγ) antibody medication used for the treatment of hemophagocytic lymphohistiocytosis (HLH),^[3][4][5] which has no cure.^[6]

Emapalumab

Monoclonal antibody
Type	Whole antibody
Source	Human
Target	IFN-gamma
Clinical data
Pronunciation	/ˈɛməpəlˌuməb/ EM-a-PAL-eu-mab[1]
Trade names	Gamifant
Other names	NI-0501, emapalumab-lzsg
AHFS/Drugs.com	Monograph
MedlinePlus	a619024
License data	US DailyMed: Emapalumab
Routes of administration	Intravenous
ATC code	L04AG09 (WHO)
Legal status
Legal status	US: ℞-only[2]
Identifiers
CAS Number	1709815-23-5
DrugBank	DB14724
ChemSpider	none
UNII	3S252O2Z4X
KEGG	D11120
Chemical and physical data
Formula	C6430H9898N1718O2038S46
Molar mass	145352.66 g·mol−1

The most common side effects include infections, hypertension, infusion-related reactions, and pyrexia.^[3]

The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.^[7]

In June 2025, the U.S. Food and Drug Administration (FDA) approved emapalumab-lzsg for the treatment of macrophage activation syndrome (MAS) in patients with Still’s disease.^[8]

Medical uses

Emapalumab is used to treat primary hemophagocytic lymphohistiocytosis (HLH) with refractory, recurrent or progressive disease or intolerance with conventional HLH therapy.^[3]

Adverse effects

In the clinical trials that lead to emapalumab's FDA approval, the most commonly reported adverse effects were infections (56%), high blood pressure (41%), infusion reactions (27%), and fever (24%).^[2][9] Serious adverse effects occurred in about half of the subjects studied in the clinical trial that led to its FDA approval.^[9]

Pharmacology

Mechanism of action

In the setting of HLH, over-secretion of IFN-γ is thought to contribute to the pathogenesis of the disease.^[2] Emapalumab binds and neutralizes IFN-γ, preventing it from inducing pathological effects.^[2]

Pharmacokinetics

Like other antibody-based medications, which are made of amino acid chains called polypeptides, emapalumab is broken down into smaller peptides via the body's normal catabolism.^[2]

Society and culture

Legal status

The U.S. Food and Drug Administration (FDA) granted orphan drug designations in 2010 and 2020,^[10][11] and breakthrough therapy designation in 2016, on the basis of preliminary data from the phase II trial.^[12]

In July 2020, and again in November 2020, the European Medicines Agency (EMA) recommended the refusal of the marketing authorization for emapalumab.^[13][14]

In June 2025, the FDA approved emapalumab-lzsg for the treatment of macrophage activation syndrome (MAS) in patients with Still’s disease.^[8]

Research

The research name of emapalumab was NI-0501.^[1] A phase II/III trial began in 2013 and is ongoing as of August 2018^[update].^[15] The trial targets patients under the age of 18 who have failed to improve on conventional treatments.^[16] This study was realised in the context of an EU-funded FP7 project, named FIGHT-HLH (306124).^{[citation needed]}