There are currently no approved treatments for primary hemophagocytic lymphohistiocytosis (pHLH), a rare, genetic condition that is characterized by hyper-inflammation due to excessive IFN-γ production. Here, Franco Locatelli, MD, PhD, of IRCCS Ospedale Pediatrico Bambino Gesu, Rome, Italy, presents the promising pivotal study results for emapalumab in pediatric pHLH. This video was recorded at the American Society of Hematology (ASH) 2018 Annual Meeting and Exposition in San Diego, CA.