Addition of Cladribine to the Standard Daunorubicine - Cytarabine (DA 3+7) Remission Induction Protocol (DAC) Contrary to Adjunct of Fludarabine (DAF) Improves the Overall Survival in Untreated Adults with Acute Myeloid Leukemia Aged up to 60 Y: A Multicenter, Randomized, Phase III PALG AML 1/2004 DAF/DAC/DA Study in 673 Patients

Abstract Our previous PALG study in 445 de novo AML patients has demonstrated that addition of cladribine to the standard daunorubicine-cytarabine (DA) remission induction regimen - DAC has a beneficial influence on both the CR rate after one induction cycle (p=0,0008) and on survival in patients older than 40 y (Leukemia 2004, 18:989–97, updated at 7 y: ASH 2006, Abstr.N#2003). The goal of this study was to evaluate the efficacy of original combination including another purine analogue fludarabine – DAF (daunorubicine 60 mg/m2/d iv, d 1–3; cytarabine (AraC) 200 mg/m2/d ci, d 1–7, and fludarabine 25 mg/m2 iv d 1–5) in untreated patients with AML, aged up to 60 y, based on head to head comparison with DAC - (DNR, AraC, Cladribine), and standard DA regimens. We evaluated earlier the DAF protocol in relapsed or refractory AML (PALG pilot study; Ann Hematol. 2008, 87:361–7. Epub 2007 Dec 12); the tolerance was good, CR 44%, LFS 38%. Primary objectives of the presented trial were: complete remission rate (CR) and overall survival (OS); secondary objectives were: toxicity and leukemia-free survival (LFS). Additional analysis was planned for patients submitted to an early bone marrow allotransplantation (alloBMT) after CR. Patients achieving CR received two courses of subsequent intensive consolidation: HAM (HD AraC, mitoxantrone) HD AraC. Reduction of consolidation was accepted in patients treated with early alloBMT. In case of partial remission (PR) after the first induction course the same regimen was repeated. Patients with no remission (NR) or with PR after 2 induction courses were withdrawn from the study. Between 09.2004 and 05.2008, 673 adult untreated AML patients aged 18–60 y, median 47 y, sex: male 49,5%, female 50,5%, treated in 18 co-operating Polish Adult leukemia Group (PALG) centres were centrally randomised to either DAF (n=225), DAC (n=224) or DA (n=224) arm (1:1:1). PML/RAR alfa positive - FAB M3 cases were excluded. The study groups were well balanced in respect of age, sex, FAB subtype, and WBC. After a single induction course the CR rate for patients receiving DAC equalling 63% was significantly higher if compared with DA - 51% (p=0,01), whereas no significant differences were noted between DAC vs. DAF - 55% and DAF vs. DA subgroups. Also the entire CR rate of 68% in the DAC arm was higher in comparison with DA one - 57% (p=0,02). No significant differences were found between DAC vs. DAF - 60%, and DAF vs. DA. At median time of 24 months (longest observation time 3,5y) the OS rate equalled 51% for the DAC treated subgroup and was higher in comparison to the standard DA arm - 39% and the DAF arm - 36% (p=0,03). The leukemia free survival rates (LFS) in DAC, DA and DAF treated cohorts equalled 51%, 32% and 41% respectively (p=NS). The early death rates of 8–10%. were similar in the studied treatment subgroups. All patients developed WHO grade IV thrombocytopenia and agranulocytosis. The frequency and severity of infections, mucositis, vomiting, diarrhoea, alopecia, polyneuropathy as well as of cardiac, liver or kidney dysfunctions were comparable in particular arms. In conclusion, this randomised study proves that the addition of cladribine to the standard DA induction regimen (DAC) improves CR rate and the overall survival in adults with AML aged up to 60 y, without additional toxicity. This beneficial effect was not observed in patients treated using the DAF protocol with fludarabine added to the standard “DA 3+7” schedule