Abstract
Background: Cladribine-based combination chemotherapy has demonstrated promising efficacy in patients with relapsed/refractory adult acute myeloid leukemia (AML), prompting its increased utilization in the frontline; in pediatrics, it has been typically reserved for relapsed or refractory cases. While fludarabine has been used more commonly as a purine analog in intensive regimens, cladribine may be an important alternative. Methods: We performed a retrospective study at MD Anderson Cancer Center from January 2015 to July 2023, which included patients aged 1-21 years with refractory or relapsed AML who received cladribine outside of a transplant conditioning. Results: A total of 30 patients were included, with a median age of 20 years (range, 2-21), and 55% being male. Similar to adults, cladribine exhibited good tolerability in pediatric and adolescent patients, with the most common adverse events being febrile neutropenia and myelosuppression. The most common grade 3 or 4 adverse events included febrile neutropenia (55%) and sepsis (26%), and there were no treatment discontinuations due to adverse events. Among patients with a median number of 2 (0-7) prior treatments, the overall response rate (CR/CRi) was 45%, and median event-free and overall survival were 6 and 12 months, respectively. Disease progression resulted in 4 deaths within 30 days of treatment. Conclusions: Cladribine was tolerated in pediatrics. No new safety signals were seen with cladribine regimens in this cohort. Response assessment is limited due to the heavily pretreated cohort. Further prospective studies are warranted on the safety and efficacy of cladribine and establish its role in pediatric, adolescent, and early young adult patients with AML.