Stem cell transplantation in children with AML not responding to other treatments

This study examined stem cell transplantation (SCT) in childhood acute myeloid leukemia (AML) patients who are not responding to other treatments. This study concluded that SCT was an effective treatment in many patients, but certain risk factors were associated with worse outcomes.

Between 5% and 23% of childhood AML patients do not respond to treatment (called refractory disease). The best treatment option for refractory AML is not yet clear. SCT is a main treatment option for patients with high-risk or relapsed AML. However, patients usually undergo transplantation after they have responded to treatment, and complete remission (CR, no sign of disease) has been achieved. It is not clear whether SCT is effective in refractory patients not in CR.

The records of 44 patients were examined. 23 had primary refractory AML (not responding to their first treatments). 21 had refractory relapsed AML. None of the patients were in CR before starting conditioning (chemotherapy) before SCT. 77% of patients underwent myeloablative conditioning (higher intensity of chemotherapy). 23% underwent reduced intensity conditioning. Patients were followed for an average of 6.8 years.

Of 42 patients, 93% achieved engraftment (when the transplanted stem cells begin producing new blood cells). 52% experienced acute graft versus host disease (when the transplanted stem cells attack healthy organs).

Off 44 patients, 68% achieved CR. 43% remained leukemia-free after 5 years. 17 patients died due to disease progression after SCT. The one-year transplant-related mortality rate was 18%.

Patients with a higher proportion of leukemia cells (more than 30%) before SCT had a higher relapse rate (60%) compared to those with less than 30% of leukemia cells (15%). Patients who were older than 10 at the time of SCT also had worse outcomes. Patients who received higher intensity conditioning and those who developed acute graft versus host disease tended to have better outcomes.

This study concluded that SCT was an effective treatment for most patients, but certain risk factors (age and proportion of leukemia cells) affected outcomes.