Retrospective analysis of prognostic factors associated with response and overall survival by baseline marrow blast percentage in patients with myelodysplastic syndromes treated with decitabine

Background: After the World Health Organization (WHO) changed the definition of acute myeloid leukemia (AML) to ≥ 20% blasts, the International Working Group (IWG) response criteria for myelodysplasia were updated. This retrospective analysis evaluated response to decitabine using updated IWG criteria in patients pooled from 2 decitabine trials. Patients and Methods: Outcomes for patients with myelodysplastic syndrome (MDS) with baseline marrow blasts ≥ 20% and < 30% (RAEB-t group) and < 20% (MDS group) were compared. Results: Patients with RAEB-t (n = 26) had a significantly shorter time from diagnosis to study treatment (7.3 vs. 18.3 months), a higher International Prognostic Scoring System (IPSS) risk (77% vs. 16% high-risk patients), and lower median baseline platelet count (62.3 vs. 112.7 × 10³/μL) vs. patients with MDS (n = 157), yet no significant difference in overall response rate (ORR) (15.4% vs. 28.0%). Patients with MDS had better duration of response (9.9 vs. 5 months; P =.024) and overall survival (OS) (16.6 vs. 9.0 months; P =.021) compared with patients with RAEB-t. Conclusion: Decitabine is active in and may benefit patients with > 20% blasts (RAEB-t).