Comparative data was needed to evaluate the effectiveness of developing treatment options for second relapsed and refractory first relapsed pediatric AML as they evolved from exclusively palliative to more typically curative in character. In addition, nothing was known regarding prognosis indicators after third-line treatment. Between 2004 and 2019, 277 of the 869 patients included in the NOPHO-DB SHIP consortium studies had the first relapse, with 98 of these patients having a refractory first relapse and 59 having a second relapse. The data on patient and illness variables in this 157-patient cohort was analyzed to assess the probability of overall survival (pOS) and factors impacting survival. There were no data on early therapeutic response or full remission. The one-year and five-year pOS rates were 22 ± 3% and 14 ± 3%, respectively. Survival did not differ significantly between refractory first and second relapsed AML. 

Late recurrence, type of third-line therapy, FLT3 mutational status, and original treatment strategy were all factors that influenced prognosis. The findings established a foundation for assessing the efficacy of developing medicines for treating children with refractory first- and second-relapsed pediatric AML, as well as evidence that select individuals receiving third-line therapy can be cured.