Design and rationale of the QUAZAR Lower-Risk MDS (AZA-MDS-003) trial: a randomized phase 3 study of CC-486 (oral azacitidine) plus best supportive care vs placebo plus best supportive care in patients with IPSS lower-risk myelodysplastic syndromes and poor prognosis due to red blood cell transfusion-dependent anemia and thrombocytopenia

CC-486 is an oral formulation of the epigenetic modifier azacitidine. In an expanded phase 1 trial, CC-486 demonstrated clinical and biological activity in patients with International Prognostic Scoring System (IPSS) lower-risk (low- and intermediate-1-risk) myelodysplastic syndromes (MDS) with poor prognostic features including anemia and/or thrombocytopenia who may have required red blood cell or platelet transfusions. The overall response rate was 40 %, including hematologic improvement in 28 % of patients and RBC transfusion independence sustained for 56 days in 47 % of patients with baseline transfusion dependence. Based on the results of this study, the randomized, placebo-controlled phase 3 QUAZAR Lower-Risk MDS trial (AZA-MDS-003) was initiated. The design and rationale for this trial comparing CC-486 with placebo for the treatment of patients with IPSS lower-risk MDS with poor prognostic features are described.