Detailed analysis of a high-risk form of ALL (Den Boer et al, 2021)
Aberrations in genes of the so-called ABL-class occur in approximately three percent of children with acute lymphoblastic leukemia (ALL). An international study of the Ponte di Legno-group, initiated by researchers from the Princess Máxima Center, demonstrates that these children have a higher risk of recurrence and dying from the disease. The results were published in The Lancet Haematology. By detailed mapping of the characteristics and outcomes of this aggressive form of ALL, this study provides an important reference for determining the potential benefit of new targeted therapies.
This form of ALL is very rare, which makes it very difficult to test new drugs in the traditional way, where one group receives the standard treatment and another group is treated with a new drug. There are strong indications that new targeted drugs, so-called tyrosine-kinase inhibitors, may be successful in this aggressive form of ALL. This study was important for providing a reference to which the results of future studies can be compared.
Researchers of the Princess Máxima Center, led by prof. dr. Monique den Boer and prof. dr. Rob Pieters, collaborated with 20 childhood cancer centers worldwide to collect data on the disease course of 122 children with ALL whose leukemic cells carry the ABL-class aberration. These children were treated between 2000 and 2018 with chemotherapy, with or without stem-cell transplantation. At that time tyrosine-kinase inhibitors were not part of the first-line treatment.
The analysis showed that 76 percent of the children were alive five years after diagnosis – a much worse outcome than in children with other forms of ALL, of whom more than 90 percent are still alive after five years. In 31 percent of the children the disease recurred within five years; in other forms of ALL this happens in less than 8 percent of the children.
Basis for future research
With this study as a basis, researchers can now determine the potential value of new targeted drugs. A new study is now ongoing to evaluate the effect of tyrosine-kinase inhibitors in children with this aggressive form of ALL.