The company has shown proof of concept for stem cell lentiviral gene therapy of FHL3 using primary cells and a genetic mouse model of FHL3. The success of the therapy is derived from the use of Expression's core technology that allows for rapid generation of transgenes with high potency. The lead candidate was demonstrated to restore exocytosis and cytolytic function to primary patient cells and in mouse models.

The lead candidate is likely to be successful for treatment of FHL3 because the disease can be reversed with less than 20% genetically corrected cells, it has an autologous nature that eliminates risks due to grafts, and there is no wait time to find an antigen-matched donor, according to Trent Spencer, PhD, president of Expression Therapeutics.

FHL3 is a hyperinflammatory disease that causes multiorgan damage leading to premature death. The company expects rapid progress for gene therapies targeting other common forms of hemophagocytic lymphohistiocytosis as well.