Effects of Azacitidine (AZA) Vs Conventional Care Regimens (CCR) in Elderly (≥75 years) Patients (Pts) with Myelodysplastic Syndromes (MDS) from the AZA-001 Survival Trial (2008)

Abstract Background. A recent phase III trial (AZA-001) showed AZA is the first treatment to significantly extend overall survival (OS) in higher-risk MDS patients (pts) (Blood2007;110:817). MDS incidence increases with age resulting in limited treatment options, particularly for those ≥75 years of age, given the poor tolerability and ineffectiveness of cytotoxic therapies. This subgroup analysis compared the effects of AZA vs CCR on OS, hematologic improvement (HI), transfusion independence (TI), and tolerability in pts ≥75 yrs of age. Methods. Higher-risk MDS (FAB: RAEB, RAEB-T, CMML and IPSS: Int-2 or High) pts were enrolled. All pts were pre-selected by site investigators – based on age, performance status, and comorbidities – to receive 1 of 3 CCR: best supportive care only (BSC); lowdose ara-C (LDAC), or intensive chemotherapy (IC). Pts were then randomized to AZA (75 mg/m2/d SC × 7d q 28d), or to CCR. Those randomized to AZA received AZA; those randomized to CCR received their pre-selected treatment. Randomization was stratified based on FAB subtype (RAEB and RAEB-T) and IPSS (Int-2 or High). Erythropoiesis stimulating agents were disallowed. OS was assessed using Kaplan-Meier (KM) methods and HI and TI were assessed per IWG 2000. To adjust for baseline imbalances, a Cox proportional hazards model was used, with ECOG status, LDH, number of RBC transfusions, Hgb, and presence or absence of -7/del(7q) at baseline as variables in the final model. Adverse events (AEs) were evaluated using NCI-CTC v. 2.0. Results. Of all enrolled pts (N=358, median age 69 yrs), 87 pts (24%) were ≥75 yrs of age (AZA n=38, CCR n=49 [BSC, n=33; LDAC, n=14; IC, n=2]). The majority of pts randomized to CCR received BSC only, suggesting clinicians are generally reticent to use active treatment in this population. Similar to the overall AZA-001 results, treatment with AZA was associated with prolonged survival in pts ≥75 yrs of age, with KM median OS in the AZA group not reached at 17.7 months of follow-up, vs KM median OS for CCR at 10.8 months (HR: 0.48 [95%CI: 0.26, 0.89]; p=0.0193). In these pts, OS rates at 2 years were significantly higher in the AZA group vs CCR: 55% vs 15% (p=0.0003). Two-fold more RBC transfusion-dependent pts at baseline in the AZA group achieved TI vs CCR: 10/23 (44%) vs 7/32 (22%), p=0.1386, respectively. Similarly, more pts in the AZA group achieved HI (major + minor) vs CCR: 58% vs 39%, (p=0.0875), respectively. As previously reported, AZA was generally well tolerated. Anemia, neutropenia, and thrombocytopenia were seen in 42%, 66%, and 71% of pts in the AZA group, respectively, vs 47%, 26%, and 40% in the CCR group, who were predominately receiving BSC only. Infections were reported by 79% and 60% of AZA and CCR pts, respectively. Discontinuations due to an AE occurred in 13% of AZA and 8% of CCR pts ≥75 yrs of age. Conclusion. Data from this subgroup analysis indicate pts ≥75 yrs of age with higher-risk MDS receiving active treatment with AZA experience significantly prolonged 2-year OS and reduced risk of death. AZA is generally well tolerated in this elderly patient population.