ORLANDO, Fla.—Patients with myelodysplastic syndrome (MDS) previously treated with intensive regimens had responses to decitabine similar to those who were treatment-naïve, suggesting this population should be considered for this hypomethylating therapy, results of a retrospective analysis have found.

Elias Jabbour, MD, of MD Anderson Cancer Center, Houston, Texas, and colleagues sought to determine the effect of prior MDS treatment on overall response rate (ORR), duration of response, time to response, and overall survival (OS) in patients who had received decitabine, which is active and has an acceptable safety profile for the treatment of all FAB subtypes of MDS. They examined results of a phase 3, 3-day dosing study and a phase 2, 5-day dosing study that included 188 patients, 54 of whom had prior treatment for MDS that consisted of cytotoxic chemotherapy (n=31), immunomodulators (n=21), stem cell transplant (n=4), monoclonal antibodies (n=2), oblimersen (n=1), or HMAs (n=1).

Patients were stratified based on prior treatment (PT, n=54) for MDS or no prior treatment (NPT, n=134), the investigators outlined in a poster presentation at the 52nd American Society of Hematology Annual Meeting and Exposition. Descriptive statistics quantified differences between the two groups for baseline characteristics, response rates (based on International Working Group 2006 consensus criteria), safety, and survival data.

Patients in the PT group had a longer time from diagnosis and a shorter duration of improvement (median 208 days) than those in the NPT group (median 296 days, p=NS) for the 5-day dosing study. The NPT group had a greater percentage of patients with International Prognostic Scoring System risk scores of high and int-2; in addition, more patients in the 5-day dosing study had FAB classification of refractory anemia with excess blasts (RAEB) and RAEB-t (n=45), whereas the baseline PT group had a greater number of patients with chronic myelomonocytic leukemia (n=8).

ORR, overall improvement rate (OIR), and median survival were greater in NPT patients with no significant difference observed between the groups. Please click here for more study data.