MDS and JMML are two rare forms of blood cancer in children. A stem cell transplant is the only curative treatment for these children. If the disease subsequently returns (relapses), a second stem cell transplant is possible, but unfortunately the prognosis then is poor.
The drug azacitidine is already used in other blood cancers. If MDS or JMML returns, treatment with azacitidine could possibly be a good way to control the disease before a second stem cell transplant is given. To investigate this, international cooperation was essential, since these are very rare cancers that occur in only a few children per year in the Netherlands.
The study ran from June 2013 to March 2019. A total of six children with MDS and four children with JMML were treated with the drug azacitidine after their disease returned. Although there were side effects, such as adverse effects on bone marrow, the children generally tolerated the drug well.
In the children with relapsed MDS, azacitidine only had a minor effect: the disease did not diminish, but remained stable in five of the six children. Four of them received a second stem cell transplant, and were still alive after a year. The children with relapsed JMML responded better to treatment with azacitidine: in three of the four children, the disease disappeared completely or partially. They then received a second stem cell transplant, and two of them were still alive after one year.
This study shows that azacitidine at the dose used (75 mg/m2) can be safely given to children with relapsed MDS or JMML. Although the long-term benefit is not yet clear, azacitidine appears to be an effective agent for children with relapsed JMML.
The scientific publication can be found here: Rubio-San-Simón A, van Eijkelenburg NKA, Hoogendijk R, et al. Azacitidine (Vidaza®) in Pediatric Patients with Relapsed Advanced MDS and JMML: Results of a Phase I/II Study by the ITCC Consortium and the EWOG-MDS Group (Study ITCC-015). Paediatr Drugs. 2023 Nov;25(6):719-728.