Postinduction Treatment for Specific ALL Subgroups
Evidence (allogeneic SCT in first remission for infants with MLL translocations):
- On a Japanese clinical trial conducted between 1998 and 2002, all infants with MLL-rearrangement were intended to proceed to allogeneic SCT from the best available donor (related, unrelated, or umbilical cord) 3 to 5 months after diagnosis.
- The 3-year EFS for all enrolled infants was 44%. This result was due, in part, to the high frequency of early relapses, even with intensive chemotherapy; of the 41 infants with MLL-rearrangement on that study who achieved complete remission (CR), 11 infants (27%) relapsed prior to proceeding to transplant.
- In a COG report that included 189 infants treated on CCG or POG infant ALL protocols between 1996 and 2000, there was no difference in EFS between patients who underwent SCT in first CR and those who received chemotherapy alone.
- The Interfant clinical trials group, after adjusting for waiting time to transplantation, also did not observe any difference in disease-free survival (DFS) in high-risk infants (defined by prednisone response) with MLL translocations treated on the Interfant-99 trial with either allogeneic SCT in first CR or chemotherapy alone.
- In a subset analysis from the same trial, allogeneic SCT in first remission was associated with a significantly better DFS for infants with MLL translocations who were younger than 6 months at diagnosis and had either a poor response to steroids at day 8 or leukocyte levels of at least 300 g/L. In this subset, SCT in first remission was associated with a 64% reduction in the risk of failure resulting from relapse or death compared with chemotherapy alone.
Treatment options for infants withoutMLLtranslocations
The optimal treatment for infants without MLL translocations also remains unclear.
- On the Interfant-99 trial, patients without MLL translocations achieved a relatively favorable outcome with the cytarabine-intensive treatment regimen (4-year EFS was 74%).
- A favorable outcome for this subset of patients was obtained in a Japanese study using therapy comparable to that used to treat older children with ALL; however, that study was limited by small numbers.