FDA Approves Gamifant, the First Drug to Treat Hemophagocytic Lymphohistiocytosis
The FDA has approved emapalumab for the treatment of both pediatric and adult patients with primary hemophagocytic lymphohistiocytosis who have refractory, recurrent or progressive disease or had an inadequate response or intolerance to conventional therapy, according to a press release.
Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe hyperinflammation caused by uncontrolled proliferation of activated lymphocytes and macrophages, which can result in extensive organ damage. Despite its severity, primary HLH is relatively rare, affecting less than one in 100,000 children, for whom there was previously no approved treatment.
“Primary HLH is a rare and life-threatening condition typically affecting children and this approval fills an unmet medical need for these patients,” Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, said in the release. “We are committed to continuing to expedite the development and review of therapies that offer meaningful treatment options for patients with rare conditions.”
An interferon gamma-blocking antibody, emapalumab (Gamifant; Sobi, Novimmune SA) was approved by the FDA based on data from a multicenter, open-label, single-arm pivotal phase 2/3 clinical study, which enrolled 27 pediatric patients with suspected or confirmed primary HLH with either refractory, recurrent or progressive disease during conventional HLH therapy or who were intolerant of conventional HLH therapy.
The study achieved its primary endpoint, with 63% of patients (P = 0.013) demonstrating an overall response at the end of treatment, defined as achievement of either a complete or partial response, or HLH improvement. Additionally, 70% of patients were able to proceed to hematopoietic stem-cell transplantation.
“I applaud the FDA approval of Gamifant for the treatment of primary hemophagocytic lymphohistiocytosis,” Jeff Toughill, president and CEO of the Histiocytosis Association, said in a press release. “We are excited that this drug will be available to patients diagnosed with this rare, life-threatening disease, and we are optimistic that this approval will help to increase awareness and improve diagnosis, ultimately giving more patients a chance.”
According to the FDA, the most common adverse events associated with emapalumab in clinical trials were fever, hypertension, infections, infusion-related reactions and low potassium; however, patients receiving emapalumab should refrain from receiving live vaccines and should be tested for latent tuberculosis.