Early recovery of the platelet count after decitabine-based induction chemotherapy is a prognostic marker of superior response in elderly patients with newly diagnosed acute myeloid leukaemia

BackgroundDefinite prognostic clinical factors of benefit for decitabine-based induction chemotherapy in elderly patients newly diagnosed with acute myeloid leukaemia (AML) are not identified. This study was designed to explore the potential biomarker, especially regeneration of haematopoiesis, of treatment response and survival in elderly patients with newly diagnosed AML.MethodWe analysed the clinical data of 117 elderly AML patients who were treated with a decitabine dose of 15mg/m(2) for 5days, granulocyte colony-stimulating factor of 300g/d for priming, plus cytarabine 10mg/m(2) q12h for 7days and aclarubicin 10mg/d for 4days (D-CAG).ResultsAfter initial induction chemotherapy, the overall response rate and complete remission (CR) were 71.8% and 58.1%, respectively. Patients responding to the D-CAG regimen achieved higher platelet counts on day 14 after initial treatment (p<0.001). Median counts were 59.5x10(9)/L in the CR group, 37x10(9)/L in the partial remission group and 28x10(9)/L in the non-responsive group. We then classified patients into those who achieved platelet counts60x10(9)/L or 100x10(9)/L on day 14 after D-CAG vs. those who did not. Platelet counts60x10(9)/L or 100x10(9)/L on day 14 were significantly associated with superior CR, overall survival and disease-free survival (80.9% vs. 45.3% p<0.001,16.5 vs. 9.1months p=0.009 and 16.3 vs. 7.4months p=0.024; 85.2% vs. 50% p=0.001, 31 vs. 10.1months p=0.003 and 16.9 vs. 8.9months p=0.006). Multivariate analysis confirmed that poor cytogenetics (p=0.010) and FLT3-ITD mutation (p=0.007) were identified as independent factors of OS, but not platelet count (p=0.091). However, platelet count100x10(9)/L on day 14 was an independent prognostic factor of CR and DFS.ConclusionPlatelet count recovery on day 14 after D-CAG induction chemotherapy is associated with response.Trial registrationD-CAG regimen was registered on ChicTR with number 11001700.