RESUMO
Treatment with azacitidine (AZA) has been suggested to be of benefit for higher-risk myelodysplastic syndrome (HR-MDS) patients with chromosome 7 abnormalities (Abn 7). This retrospective study of 235 HR-MDS patients with Abn 7 treated with AZA (n = 115) versus best supportive care (BSC; n = 120), assessed AZA treatment as a time-varying variable in multivariable analysis. A Cox Regression model with time-interaction terms of overall survival (OS) at different time points confirmed that, while chromosome 7 cytogenetic categories (complex karyotype [CK] versus non-CK) and International Prognostic Scoring System risk (high versus intermediate-2) retained poor prognosis over time, AZA treatment had a favourable impact on OS during the first 3 years of treatment compared to BSC (Hazard ratio [HR] 0·5 P < 0·001 at 1 year, 0·7 P = 0·019 at 2 years; 0·73 P = 0·029 at 3 years). This benefit was present in all chromosome 7 categories, but tended to be greater in patients with CK (risk reduction of 82%, 68% and 53% at 1, 3 and 6 months in CK patients; 79% at 1 month in non-CK patients, P < 0·05 for all). AZA also significantly improved progression-free survival (P < 0·01). This study confirms a time-dependent benefit of AZA on outcome in patients with HR-MDS and cytogenetic abnormalities involving chromosome 7, especially for those with CK.