Why was this study done?
Nearly 500 children are found to have acute myeloid leukemia (AML) each year in the U.S. About half of these children are cured with standard therapy, which means they show no signs of leukemia for 5 years.
The study’s main goal was to improve the cure rate of children and adolescents with AML.
The study’s other goals were to:
- Compare the response rates after 1 course of chemotherapy (chemo) in patients treated with the standard drug combination of cytarabine, daunorubicin, and etoposide versus the experimental combination of clofarabine and cytarabine
- Find out if natural killer (NK) cell therapy will be useful for patients with standard-risk AML
- Learn more about the biology and genetic makeup of AML by studying blood and bone marrow samples
- Learn more about how AML treatment drugs work in the body of patients with AML
- Learn how the drugs affect the body and how patients’ own genetic makeup may predict who will have more side effects and who will respond to treatment
- Find out if we can prevent major infections by giving antibiotics and antifungal drugs when blood counts are very low
When was this study done?
The study opened in August 2008 and closed in March 2017.
What did the study consist of?
- All patients were randomly assigned to get clofarabine and cytarabine or cytarabine, daunorubicin, and etoposide as their first treatment course
- Low-risk patients got 4 courses of chemotherapy
- Standard-risk patients who had appropriate NK cell donors had 4 courses of chemotherapy followed by an infusion of NK cells. Other standard-risk patients got 4 courses of chemotherapy without NK cell therapy.
- High-risk patients got 2 or 3 courses of chemotherapy followed by hematopoietic cell transplantation.
What did we learn from this study?
After 2 courses of therapy, 92.3% of the 285 patients were in complete remission (no evidence of leukemia).
Minimal residual disease (small numbers of leukemia cells) was present on Day 22 of therapy in 47% of patients who got clofarabine and cytarabine and in 35% of patients who got cytarabine, daunorubicin, and etoposide. Despite this result, the 3-year event-free survival rate did not differ significantly between the 2 treatment arms. The 3-year overall survival rate was 75% for patients who got clofarabine and cytarabine and 65% for those who got cytarabine, daunorubicin, and etoposide.
Patients who got NK cells tolerated the treatment well. But the therapy with NK cells did not improve survival rates.
Scientists looked for signs of minimal residual disease in the blood and bone marrow of AML patients. Patients who were at risk for relapse showed signs of minimal residual disease in their blood as early as 8 days after treatment, as well as in their bone marrow 28 days after treatment. This could help doctors identify at-risk patients earlier.
What are the next research steps as a result of this study?
The findings suggest that the use of clofarabine with cytarabine during remission induction might reduce the need for anthracycline and etoposide in pediatric patients with AML and may reduce rates of cardiomyopathy and treatment-related cancer.
This study also shows the importance of finding minimal residual disease early to identify patients at risk for relapse. More studies are planned to detect this risk by testing blood and bone marrow samples and looking for DNA changes. This will help doctors select the best therapy for each patient.
How does this study affect my child?
Every childhood cancer survivor should have long-term follow-up care. Through the St. Jude After Completion of Care clinic, your child will get information and guidance for care after treatment. Please speak with your St. Jude doctor about specific guidelines that apply to your child.
For more information
Please talk with your child’s St. Jude doctor about questions or concerns you have as a result of this study.
Publications generated from this study:
Clofarabine Can Replace Antracyclines and Etoposide in Remission Induction Therapy for Childhood Acute Myeloid Leukemia: The AML08 Multicenter, Randomized Trial. Rubnitz JE, Lacayo NJ, Inaba H, Heym K, Ribeiro RC, Taub J, McNeer J, Degar B, Schiff D, Yeoh AE, Coustan-Smith E, Wang L, Triplett B, Raimondi SC, Klco J, Choi J, Pounds S, Pui CH. J Clin Oncol. 2019 Aug 10;37(23):2072-2081.
https://www.ncbi.nlm.nih.gov/pubmed/31246522
A Phase II Clinical Trial of Adoptive Transfer of Haploidentical Natural Killer Cells for Consolidation Therapy of Pediatric Acute Myeloid Leukemia. Nguyen R, Wu H, Pounds S, Inaba H, Ribeiro RC, Cullins D, Rooney B, Bell T, Lacayo NJ, Heym K, Degar B, Schiff D, Janssen WE, Triplett B, Pui CH, Leung W, Rubnitz JE. J Immunother Cancer. 2019 Mar 20; 7: 81. https://pubmed.ncbi.nlm.nih.gov/30894213/
Clinical impact of minimal residual disease in blood and bone marrow of children with acute myeloid leukemia. Karol SE, Coustan-Smith E, Pounds S, Wang L, Inaba H, Ribeiro RC, Pui CH, Klco JM, Rubnitz JE. Blood Adv. 2023 Jul 25;7(14):3651-3657. https://pubmed.ncbi.nlm.nih.gov/37058475/