Use of hypomethylating agents and associated care in patients with myelodysplastic syndromes: a claims database study

Objective: The purpose of this study is to describe patterns of hypomethylating agents (HMA) use and to compare treatment outcomes of decitabine (DAC) and azacitidine (AZA) with respect to transfusion dependence and the use of erythropoiesis-stimulating agents (ESA) treatment in commercially-insured patients with Myelodysplastic Syndromes (MDS). Research design and methods: A retrospective study using MarketScan Research Data, a large claims database studied patients who received DAC, AZA, or Supportive Care (SC) with at least two claims for MDS between January 1, 2006 and December 31, 2008. Poisson regressions were used to compare DAC and AZA on post-index number of red blood cell/platelet (RBC/PLT) transfusions and ESA treatment, controlling for age, gender, Charlson Comorbidity Index (CCI), time to HMA initiation, number of HMA cycles, and pretreatment RBC/PLT or ESA claims. No other adjustment for disease severity was made. Results: Approximately 48% of the patients were males with a mean age of 73 years (N = 2525). There were 37 DAC-treated and 60 AZA-treated patients. The length of follow-up did not significantly differ between the DAC- and AZA-treated groups (DAC = 349.2; AZA = 350.5 days); however, the number of days from MDS diagnosis to HMA therapy initiation was longer in the DAC cohort than in the AZA cohort (mean 93.7 days vs. 50.8 days, respectively, p = 0.029). Both DAC- and AZA-treated patients received similar number of treatment cycles (mean: 4.8 vs. 5.6 in DAC vs. AZA, p>0.05), with means of 4.6 days per cycle for patients receiving DAC and 7.4 days for those receiving AZA (p = 0.003). Following treatment with HMA using Poisson regression analysis, DAC-treated patients had significantly lower use of RBC/PLT transfusions (RR 0.206, p = 0.034) and similar use of ESAs compared with AZA-treated patients. Limitations of the study included the small sample size, and the fact that the majority of patients were unspecified regarding their International Prognostic Scoring System (IPSS) risk category, which did not allow for accounting for differences in disease severity. Conclusions: In MDS patients treated with an HMA, treatment with DAC was associated with less frequent transfusions than with AZA treatment. Further studies with the ability to control for disease severity are warranted.