Background: Acute myeloid leukaemia (AML) with t (8;21) or inv (16), called core binding factor (CBF) AML, has a favourable prognosis. However, some CBF-AML patients have persistent measurable residual disease (MRD) and are more likely to relapse after standard chemotherapy treatment. The CAG regimen, composed of cytarabine, aclarubicin and granulocyte colony-stimulating factor, has been proven to be effective and safe in treating refractory AML patients.
Method: We performed a retrospective study to evaluate the efficacy of the CAG regimen to eliminate MRD detected by RUNX1::RUNX1T1 and CBFβ::MYH11 transcript levels by quantitative polymerase chain reaction (Q-PCR) among 23 patients. Molecular response was defined as the ratio of fusion transcript after treatment to that before treatment greater than or equal to 0.5.
Result: The molecular response rate and median decrease ratio of fusion transcripts at themolecular level of the CAG regimen were 52.5% and 0.53, respectively. Among the 15 patients who had a poor molecular response to the high/intermediate-dose cytarabine regimen, the median decrease ratios of transcripts at the molecular level of high/intermediate-dose cytarabine and CAG were 1.55 and 0.53 (P=0.028), respectively, and 6 of 15 patients achieved amolecular response to CAG (40%). The median disease-free survival was 18 months, and the overall survival rate at three years among all patients was 72.7%±10.7%. The common treatment-related adverse events were nausea (100%), thrombocytopenia (39%) and neutropenia (37.5%).
Conclusion: The CAG regimen may have activity in CBF-AML patients and could provide a new option for patients who have a poor molecular response to high/intermediate-dose cytarabine.