Prospective comparison of 5- and 7-day administration of azacitidine for myelodysplastic syndromes: a JALSG MDS212 trial

The hypomethylating agent azacitidine (AZA) significantly extends overall survival (OS) in patients with higher risk myelodysplastic syndromes (MDS), when compared with other conventional care regimens, including supportive care and low-dose and intensive chemotherapy. However, the effects of 5- and 7-day treatment schedules of AZA (AZA-5 and AZA-7, respectively) on the OS of MDS patients had not been compared prospectively. We started a phase 3 trial comparing the effects of AZA-7 and AZA-5 on MDS patients with refractory anemia with excess blasts (RAEB) and RAEB in transformation (RAEB-T). However, this trial was prematurely terminated because of poor recruitment. Using all data, there was no significant difference in the OS of patients between AZA-7 (92 patients) and AZA-5 (95 patients), with the 2-year OS rates of AZA-7 and AZA-5 at 36.4% and 25.8%, respectively (P = 0.293). Adverse event profiles were similar between the two groups. Interestingly, data of the centrally diagnosed RAEB and RAEB-T cases showed that AZA-7 significantly prolonged the time to leukemia transformation compared with AZA-5 (P = 0.022), confirmed by multivariate analysis. Although this trial could not provide definite evidence, the results support the use of AZA-7 for RAEB and RAEB-T. (UMIN Clinical Trials Registry UMIN000009633).