SOBI announced that the results from the pivotal phase 2/3 study evaluating the efficacy and safety of emapalumab in patients with primary hemophagocytic lymphohistiocytosis (HLH) were published in the New England Journal of Medicine on 7 May 2020. Emapalumab is the first therapy approved by the US Food & Drug Administration (FDA) for primary HLH and is under review by the European Medicines Agency (EMA).
The open-label, single-group, phase 2–3 study enrolled patients who had received conventional therapy before enrollment (previously treated patients) and previously untreated patients who were 18 years of age or younger and had primary hemophagocytic lymphohistiocytosis. The primary efficacy end point was the overall response, which was assessed in the previously treated patients according to objective clinical and laboratory criteria. A total of 34 patients (27 previously treated patients and 7 previously untreated patients) were enrolled and 26 patients completed the study. A total of 63% of the previously treated patients and 65% of the patients who received an emapalumab infusion had a response. In the previously treated group, 70% of the patients were able to proceed to transplantation, as were 65% of the patients who received emapalumab. At the last observation, 74% of the previously treated patients and 71% of the patients who received emapalumab were alive. Emapalumab was not associated with any organ toxicity. Severe infections developed in 10 patients during emapalumab treatment. Emapalumab was discontinued in 1 patient because of disseminated histoplasmosis.
Emapalumab is a monoclonal antibody that binds to and neutralizes interferon gamma (IFNγ). In the US, emapalumab is indicated for paediatric (newborn and older) and adult primary hemophagocytic lymphohistiocytosis (HLH) patients with refractory, recurrent or progressive disease, or intolerance to conventional HLH therapy.
About Primary HLH
Primary HLH is a rare syndrome that typically presents in infancy but can also be seen in adults and is associated with high morbidity and mortality. This life-threatening disease is characterized by immune dysregulation and uncontrolled hyperinflammation. The treatment objective is to suppress the hyperinflammation and control the acute features of the disease in order to successfully bring patients to hematopoietic stem cell transplantation (HSCT).