Emapalumab, an interferon gamma-blocking antibody, is approved to treat patients of all ages (newborn and older) with primary HLH who have refractory, recurrent, or progressive disease or who cannot tolerate conventional HLH therapy. Emapalumab is the first treatment to befor primary HLH, and it is expected to be in the United States in the first quarter of 2019. The FDA previously granted emapalumab priority review, breakthrough therapy designation, orphan drug designation, and rare pediatric disease designation. The FDA’s approval of emapalumab is based on results from a phase 2/3 trial ( ).
The trial included 34 patients, 27 of whom had refractory, recurrent, or progressive disease or could not tolerate conventional HLH therapy. Patients received emapalumab in combination with dexamethasone. At the end of treatment, 63% (17/27) of patients had achieved a response, which was defined as complete response (n = 7), partial response (n=8), or HLH improvement (n = 2). A total of 70% (n=19) of patients went on to hematopoietic stem cell transplant. The most common adverse events were infections (56%), hypertension (41%), infusion-related reactions (27%), and pyrexia (24%).
Results also are scheduled to be presented at the 2018 annual meeting of the American Society of Hematology in the late-breaker abstract session ().
Emapalumab was developed by Novimmune SA. Sobi acquired global rights to the drug in August 2018.