[Safety and the Short-Term Efficacy of Venetoclax Combined with Azacitidine Followed by Cladribine in Children with Refractory/Relapsed Acute Myeloid Leukemia]

Objective: To investigate the safety and the short-term efficacy of venetoclax combined with azacitidine followed by cladribine (VAC regimen) in children with refractory/ relapsed acute myeloid leukemia (AML).

Methods: The clinical data, treatment outcomes, complications, and blood product consumption of 6 children with refractory/relapsed AML treated with VAC regimen in the Children's Hospital of Soochow University from August 2021 to December 2021 were retrospectively analyzed.

Results: Among the 6 children, there were 1 male and 5 females. 5 cases were refractory AML, and 1 case was relapsed AML, which recurred again 16 months after allogeneic hematopoietic stem cell transplantation. 4 children were accompanied by chromosomes or genes that predicted poor prognosis, such as RUNX1, FLT3-ITD, KMT2A exon 2-exon 8 dup, MLL-AF6, 7q-, KMT2A exon 2-exon 10 dup, etc. After received VAC regimen, 4 cases achieved CR+CRi, 1 case achieved PR (only MRD did not relieve, MRD was 0.59%), and 1 case was NR (but the proportion of bone marrow blasts decreased). All 6 patients had grade Ⅳ neutropenia, and 4 patients had grade Ⅳ thrombocytopenia. During the period of neutropenia, none of the 6 children developed symptoms of infection such as fever, cough, and diarrhea. No treatment-related death occurred.

Conclusion: Venetoclax combined with azacitidine followed by cladribine provides a new treatment option for patients with relapsed/refractory AML who have poor efficacy in early induction remission theragy, showing good efficacy and safety.