Vor Bio announced successful first of its kind dual editing of CD33 and CLL-1 in human hematopoietic stem cells (HSCs) demonstrating continued progress on its novel approach for the treatment of acute myeloid leukemia (AML). The data is being presented at the European Hematology Association Congress in Vienna, Austria.
The pre-clinical data demonstrates that multiplex deletion by CRISPR/Cas9 of CD33 and CLL-1 from human CD34+ hematopoietic stem and progenitor cells (HSPCs) maintained cell function and persisted long-term post engraftment in vivo, with a high-level of editing, no counterselection, and minimum translocation risk when compared to unedited control cells. In addition, genetically modifying HSPCs to remove select cell surface targets does not impair their function and these dual engineered cells showed significant protection from targeted immunotherapy in vitro.
AML is the most common type of acute leukemia in adults and is characterized by excessive proliferation of immature myeloid progenitor cells and their failure to properly differentiate into mature blood cells. Healthy donor HSC transplantation is the standard of care and currently around 40% of patients with AML who receive HSC transplantation suffer a relapse of their cancer, with two-year survival rates of less than 20%, highlighting the need for new therapeutic approaches for these patients.