Outcomes for patients with acute myeloid leukemia who receive ex vivo T cell-depleted hematopoietic stem cell transplantation

This study aimed to investigate the outcomes of patients with acute myeloid leukemia after ex vivo T cell-depleted allogeneic hemopoietic stem cell transplant.  

This study concluded that the outcomes for these patients compare favorably to an unmodified transplant and that the modified transplant leads to lower rates of graft-versus-host disease.  

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a procedure in which a person receives blood-forming stem cells from a genetically similar, but not identical, donor. This is often a sister or brother but could be an unrelated donor. Ex vivo means the cells are grown outside the body. They are taken from a donor and grown in a lab before being reintroduced to the body.  

T cell depletion (TCD) involves removing T cells. T cells' main function is to attack foreign things that enter the body. TCD should allow the transplant to work and reduce the risk of graft versus host disease (GVHD). GVHD is a common complication after an allo-HSCT. This occurs after transplant when the transplanted cells attack the body. 

The outcomes for patients with AML after and ex vivo TCD allo-HSCT have not been previously reported.  

This study involved 266 patients with AML. All patients received CD34 selected TCD allo-HSCTs while in first or second complete remission (CR). CR is when all signs of cancer are gone. 75% of patients were in first CR and 25% were in second CR. Patients were followed up for at least 2 years after the allo-HSCT.

Patients received myeloablative conditioning regimes (treatment to prepare for transplant that reduces blood cells). Patients did not receive GVHD preventative treatment. 

At 180 days, the occurrence of mild to severe short-term GVHD was 14%. At 180 days, the occurrence of severe to life-threatening short-term GVHD was 3%. At 3 years, the occurrence of long-term GVHD was 3%. 

At 3 years, the rate of non-relapse mortality (death not related to relapse – NRM) was 21%. The rate of relapse at 3 years was 21%. Overall survival (OS) at 1 year was 75%, at 3 years was 61% and at 5 years was 56%. Disease-free survival (DFS) at 1 year was 68%, at 3 years was 57% and at 5 years was 53%. 

This study concluded that the outcomes for patients with AML treated with ex vivo TCD allo-HSCT compare favorably to an unmodified transplant. It was also concluded that ex vivo TCD allo-HSCT leads to lower rates of GVHD.  

This study was based on medical records. Data might have been missing. This might have influenced the results. Further studies are needed.