Post hoc analysis of the relationship between baseline white blood cell count and survival outcome in a randomized Phase III trial of decitabine in older patients with newly diagnosed acute myeloid leukemia

Abstract

Christopher Arthur,1 Jaroslav Cermak,2 Jacques Delaunay,3 Jirí Mayer,4 Grzegorz Mazur,5 Xavier Thomas,6 Agnieszka Wierzbowska,7 Mark M Jones,8 Erhan Berrak,8 Hagop Kantarjian9 1Department of Haematology, Royal North Shore Hospital, Sydney, NSW, Australia; 2Institute of Hematology and Blood Transfusion, Prague, Czech Republic; 3Department of Clinical Hematology, University of Nantes, Nantes, France; 4Department of Internal Medicine, Masaryk University Hospital Brno, Central European Institute of Technology, Brno, Czech Republic; 5Department of Hematology, Wroclaw Medical University, Wroclaw, Poland; 6Department of Hematology, Edouard Herriot Hospital, Lyon, France; 7Copernicus Memorial Hospital, Lodz, Poland; 8Oncology Product Creation Unit, Eisai Inc., Woodcliff Lake, NJ, USA; 9Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA Background: In a Phase III trial, 485 patients (≥65 years) with newly diagnosed acute myeloid leukemia received decitabine 20 mg/m2 intravenously for 5 days every 4 weeks or a treatment choice (supportive care or cytarabine 20 mg/m2 subcutaneously for 10 days every 4 weeks). Materials and methods: We summarized overall and progression-free survival by baseline white blood cell count using two analyses: <1, 1–5, >5×109/L; ≤10 or .10×109/L. Results: There were 446 deaths (treatment choice, n=227; decitabine, n=219). Median overall survival was 5.0 (treatment choice) versus 7.7 months (decitabine; nominal P=0.037). Overall survival differences between white blood cell groups were not significant; hazard ratios (HRs) favored decitabine. Significant progression-free survival differences favored decitabine for groups 1–5×109/L (P=0.005, HR =0.67), greater than 5×109/L (P=0.027, HR =0.71), and up to 10×109/L (P=0.003, HR =0.72). Conclusion: There was a trend toward improved outcome with decitabine, regardless of baseline white blood cell count. Keywords: decitabine, acute myeloid leukemia, prognosis, leukemia, adult