6576 Background: Patients (pts) receiving red blood cell (RBC) transfusions are exposed to various side-effects such as intolerance reactions, iron overload, and alloimmunization risks. Reduction in RBC transfusions plus improvement in quality of life was demonstrated in pts with MDS treated with azacitidine in the phase 3 randomized study (9221) conducted by the CALGB (JCO 2002;20:2429). Azacitidine also demonstrated beneficial effects on platelets and neutrophils. To further explore transfusion results in 9221, we compared RBC and platelet transfusion requirements in pts treated with azacitidine across 3 CALGB studies (phase 2 intravenous [IV] 8421, phase 2 subcutaneous [SC] 8921, and Phase 3 SC 9221). METHODS Baseline was defined as 90 days immediately prior to randomization or crossover, as appropriate. Transfusion independence was defined as maintaining independence for ≥56 days (IWG criteria). Duration of transfusion independence was defined as the date of last transfusion to the date of the next transfusion or date of censoring. Proportions of pts who became RBC or platelet independent during the study were compared, as were the median durations of independence. RESULTS Compared with pts treated with IV azacitidine, a greater percent of pts treated with SC azacitidine achieved independence ( Table ), but the IV study (8421) enrolled only pts with advanced MDS. Differences of 10% in proportions of pts registered or randomized to SC azacitidine who achieved transfusion independence were noted in the phase 2 and 3 studies for RBCs (8921: 35%; 9221: 45%) and for platelets (8921: 43%; 9221: 53%). Median duration of RBC independence in 8921 was 221 days, which was within 6% of that observed for pts randomized to azacitidine in 9221 (235 days). CONCLUSIONS These results provide further support that azacitidine has beneficial effect on erythropoiesis and thrombopoiesis. Patients with MDS treated with azacitidine may develop RBC or platelet transfusion independence. [Table: see text] [Table: see text].
L. Silverman, B. Peterson, J. Holland
Journal of clinical oncology : official journal of the American Society of Clinical Oncology