General Information

Gamifant (emapalumab-lzsg) is a monoclonal antibody that binds to and neutralizes interferon gamma (IFNy), which is thought to contribute to hemophagocytic lymphohistiocytosis.  

Gamifant is specifically indicated for the treatment of adult and pediatric (newborn and older) patients with primary hemophagocytic lymphohistiocytosis (HLH) with refractory, recurrent or progressive disease or intolerance with conventional HLH therapy.

Gamifant is supplied as a solution for intravenous administration. The recommended starting dose is 1 mg/kg given as an intravenous infusion over 1 hour twice per week (every three to four days). Doses subsequent to the initial dose may be increased based on clinical and laboratory criteria. Administer Gamifant until hematopoietic stem cell transplantation (HSCT) is performed or unacceptable toxicity. Discontinue Gamifant when a patient no longer requires therapy for the treatment of HLH.

Mechanism of Action

Gamifant (emapalumab-lzsg) is a monoclonal antibody that binds to and neutralizes interferon gamma (IFNγ). Nonclinical data suggest that IFNγ plays a pivotal role in the pathogenesis of hemophagocytic lymphohistiocytosis by being hypersecreted.

Side Effects

Adverse effects associated with the use of Gamifant may include, but are not limited to, the following:

• infections
• hypertension
• infusion-related reactions
• fever

Clinical Trial Results

The FDA approval of Gamifant was based on results from a global, multicenter, open-label, single-arm pivotal Phase 2/3 clinical study which enrolled 34 primary HLH patients. The efficacy of Gamifant was evaluated in the cohort of 27 patients with refractory, recurrent or progressive disease during conventional HLH therapy or who were intolerant to conventional HLH therapy. Gamifant was administered concomitantly with dexamethasone, which could be tapered during the study. The efficacy of Gamifant was based upon overall response rate (ORR) at the end of treatment, defined as achievement of either a complete or partial response or HLH improvement. The primary endpoint was achieved, with 63% of patients demonstrating an overall response at the end of treatment. In addition, 70% of patients proceeded to hematopoietic stem cell transplant (HSCT). Of the 27 refractory patients treated in the study, 82% had a genetically confirmed primary HLH diagnosis.