FDA approves first ever therapy for ultra rare primary haemophagocytic lymphohistiocytosis

The partnership of Sobi and Novimmune has revealed that their interferon gamma (IFNγ) blocking antibody Gamifant (emapalumab-lzsg) has received approval from the FDA for the treatment of the primary haemophagocytic lymphohistiocytosis (HLH) with in paediatric and adult patients with refractory, recurrent or progressive disease or intolerance to conventional HLH therapy.

The treatment becomes the first approved in the US for the ultra-rare syndrome, which is associated with high rates of morbidity and mortality. The decision was based on Phase 2/3 data which demonstrated that the therapy met its primary endpoint, with a "clinically meaningful and statistically significant" section of participants experiencing overall response, while 70% proceeded to haematopoietic stem-cell transplantation (HSCT).

 "Primary HLH is a rare and life-threatening condition typically affecting children and this approval fills an unmet medical need for these patients," commented Dr Richard Pazdur, 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. "We are committed to continuing to expedite the development and review of therapies that offer meaningful treatment options for patients with rare conditions."

Dr Michael Jordan, the trial’s Primary Investigator and a physician-scientist in the division of Bone Marrow Transplantation and Immune Deficiency at Cincinnati Children's Hospital Medical Center HLH Center of Excellence, explained why the ruling is so significant: "HLH is a disorder of immune regulation in which many cytokines are deranged, but interferon gamma appears to play a critical role. While we have long understood the pivotal role of this cytokine in HLH, until emapalumab's approval we did not have a medicine that could specifically hit this target. Emapalumab represents an entirely new approach to treating primary HLH and helping these very sick patients reach haematopoietic stem cell transplant."

Sobi President and CEO Guido Oelkers also remarked on the news, saying: "The FDA approval of Gamifant marks an important milestone in Sobi’s vision to bring transformative treatments to patients with a high medical need. Gamifant will add significant strength to Sobi’s Immunology franchise, along with Kineret and the recent acquisition of the US rights to Synagis. We would like to acknowledge the excellent work done by Novimmune to develop and bring this important treatment to approval and Sobi will now focus on ensuring a successful commercialisation of Gamifant for the benefit of HLH patients in the US."