Impact of Iron Chelation Therapy on Overall Survival and AML Transformation in Lower Risk MDS Patients Treated At the Moffitt Cancer Center

Elevated serum ferritin levels and red blood cell transfusion dependence are associated with poor outcome in patients with lower risk myelodysplastic syndromes (MDS). Few retrospective and observational studies suggest that iron chelation therapy (ICT) may favorably impact outcome in lower risk MDS. The vast majority of patients in those studies were treated with deferoxamine (Desferal). Two studies reported that oral deferasirox (Exjade) significantly decreases ferritin level over time in MDS. An ongoing randomized placebo-controlled trial (TELESTO) is designed to address the impact of deferasirox on overall survival (OS) in lower risk MDS. We examined the impact of ICT predominantly deferasirox in lower risk MDS patients treated at the Moffitt Cancer Center (MCC).

Patients were retrospectively identified from the MCC database and individual patients' records reviewed. Inclusion criteria included lower risk MDS patients defined as low or intermediate-1 (int-1) risk disease by the international prognostic scoring system (IPSS) and serum ferritin level ≥ 1000 ng/ml. Patients were divided into two comparator groups: ICT vs. no ICT. Baseline characteristics were compared between the two groups; chi square test was used for categorical variables and t-test for continuous variables. The primary endpoint was overall survival compared between the two groups using Kaplan-Meier estimates. Cox regression was used for multivariate analysis. All analyses were conducted using SPSS version 19.0 statistical software.

Between July 2001 and July 2009, 97 patients with lower risk MDS and serum ferritin ≥ 1000 ng/ml were identified. Forty five (46.4%) received ICT and 52 did not. The ICT included deferasirox in 35 patients and deferoxamine in 10 patients. The baseline characteristics between the two groups (ICT and no ICT) are summarized in (table-1). No statistically significant difference in baseline characteristics was observed except more patients in the ICT group were transfusion dependent. The median duration of follow up was 85.7 month from time of diagnosis.

The median OS was 59 months (95%CI 22–48) for patients who received ICT compared to 33.7 months (95%CI 38–80) for patients who did not receive ICT (P= 0.013). After adjustment for age and cytogenetics in Cox multivariable analysis, ICT was associated with better OS (HR 0.52, 95%CI 0.31–0.87, P= 0.013). The rate of AML transformation was 21.2% in patients who did not receive ICT compared to 15.6% in those who had ICT. (p=0.33).

ICT in lower risk MDS patients with elevated serum ferritin ≥ 1000 ng/ml was associated with improved overall survival and a trend to lower AML transformation. Results of ongoing randomized clinical study with deferasirox are needed to confirm the retrospective data.

Komrokji:Novartis: Honoraria, Research Funding.