5 '-Azacitidine in myelodysplastic syndromes with inversion of chromosome 3

The efficacy of azacitidine has been proved in two large phase III trials in intermediate-2 or high-risk myelodysplastic patients. The CALGB (Cancer and Leukemia Group B) study showed significantly prolonged median time to progression to leukaemia and/or death, whereas AZA 001 trial showed a prolonged overall survival (OS) compared with conventional care regimens.1, 2, 3 Recently, it has been reported that abnormal karyotype independently predicted lower response rates to azacitidine and that intermediate- and poor-risk cytogenetics independently predicted poorer OS.4 Inversion of chromosome 3 (inv(3)(q21;q26)), with EVI-1 (ecotropic viral integration site 1) transcriptional activation, is relatively common in myeloid malignancies and was reported in acute myeloid leukaemia, chronic myeloid leukaemia in blast crisis and myelodysplastic syndromes (MDS).5 Usually, a distinct phenotype is associated with this cytogenetic aberration, such as trilineage dysplasia, thrombocytosis, young age, possible association with monosomy 7 or other complex karyotype changes, and poor prognosis because of scarce response to conventional chemotherapy.6 No data were reported on the sensibility of MDS patients with this cytogenetic alteration to azacitidine. We here describe two MDS patients with inv(3)(q21;q26) who achieved morphological and cytogenetic response with azacitidine.