Vor Bio (Nasdaq: VOR), a clinical-stage cell and genome engineering company, today 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.
“As most tumor antigens are also expressed on normal blood cells or bone marrow, traditional targeted immunotherapy increases the risk of severe cytopenia,” explained Tirtha Chakraborty, Ph.D., Vor Bio’s Chief Scientific Officer. “Our pre-clinical proof-of-concept data shows that the knockout of both CD33 and CLL-1 from allogeneic HSC grafts can restrict these antigens to only the patients’ AML cells, thereby protecting the healthy HSCs and making them resistant to the toxic effects of targeted therapies. These data validate that CD33 and CLL-1 may both be independently biologically dispensable, where we envision our multiplex treatment system has the potential to avoid concerns regarding tumor heterogeneity or escape mechanisms.”
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.
Vor Bio is developing a first-in-class treatment approach consisting of gene-edited HSC transplants that are designed to be resistant to targeted therapies, enabling post-transplant use of powerful therapies such as CAR-Ts or other targeted immuno-therapies. This new approach has the potential to protect healthy cells from the damaging effects of cancer-targeted therapies, leaving the cancerous cells exposed and, for the first time, allowing these targeted therapies to be truly cancer-specific sparing the healthy cells.
The full poster (P1249) is available on the Vor Bio corporate website at https://www.vorbio.com/