Residual Blast Cells in Bone Marrow on Day 15 Following Remission Induction Therapy for Acute Myeloid Leukemia Is Associated with Long-Term Prognosis: A Retrospective Analysis of the JALSG AML201 Study

Background The percentage of blasts in the bone marrow in the early stage of remission induction therapy for acute myeloid leukemia (AML) has been reported to affect not only remission rate, but also long-term prognosis. If early post-treatment response to therapy was determined to affect prognosis, this finding could be a basis for selection of a proactive treatment such as hematopoietic stem cell transplantation; however, the proper assessment period and the percentage of blast cell survival vary among reports. Therefore, we retrospectively analyzed the relationship between prognosis and the percentage of blasts in the bone marrow in the early post-treatment stage in cases registered for the AML201 study conducted by the Japan Adult Leukemia Study Group (JALSG). Patients and Methods The JALSG AML201 study was a multicenter randomized study in which 1064 patients with newly diagnosed AML patients were registered between December 2001 and December 2005. For remission induction therapy, we compared standard-dose idarubicin or high-dose daunorubicin in combination with cytarabine. For consolidation therapy, we compared standard-dose multiagent chemotherapy or high-dose cytarabine alone, and no apparent differences were observed in overall survival (OS) between both treatment groups. The percentage of blasts in the bone marrow on day 15 was strongly associated with remission; using the receiver operating characteristic curve as a reference, we divided patients into a ≥5% and a Results Among the 1064 patients registered for the JALSG AML201 study, 600 patients for whom bone marrow examination was performed on Day 15 were selected as subjects for the present study. The patients consisted of 375 men and 225 women with a median age of 47 years (15-64 years). A total of 377 patients (62.8%) had Conclusion As an early assessment of bone marrow following remission induction therapy, having Disclosures Fujita: Chugai Pharmaceutical CO.,LTD.: Honoraria. Kiyoi:Novartis Pharma K.K.: Research Funding; JCR Pharmaceutlcals Co.,Ltd.: Research Funding; FUJIFILM Corporation: Patents & Royalties, Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Phizer Japan Inc.: Research Funding; Toyama Chemikal Co.,Ltd.: Research Funding; AlexionpharmaLLC.: Research Funding; Celgene Corporation: Consultancy; Nippon Shinyaku Co., Ltd.: Research Funding; Alexion Pharmaceuticals: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding; MSD K.K.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Mochida Pharmaceutical Co., Ltd.: Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Astellas Pharma Inc.: Consultancy, Research Funding; Eisai Co., Ltd.: Research Funding; Yakult Honsha Co.,Ltd.: Research Funding. Naoe:Amgen Astellas BioPharma K.K.: Honoraria; Fujifilm Corporation: Honoraria, Patents & Royalties, Research Funding; Sumitomo Dainippon Pharma Co.,Ltd.: Honoraria, Research Funding; TOYAMA CHEMICAL CO.,LTD.: Research Funding; Pfizer Inc.: Research Funding; CMIC Co., Ltd.: Research Funding; Astellas Pharma Inc.: Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Honoraria, Research Funding; Celgene K.K.: Honoraria, Research Funding; Chugai Pharmaceutical Co.,LTD.: Honoraria, Patents & Royalties; Bristol-Myers Squibb: Honoraria; Kyowa-Hakko Kirin Co.,Ltd.: Honoraria, Patents & Royalties, Research Funding; Otsuka Pharmaceutical Co.,Ltd.: Honoraria, Research Funding.