Azacitidine (Vidaza®) is a
pyrimidine nucleoside analogue of
cytidine. This article reviews the clinical efficacy and tolerability of
azacitidine in the treatment of patients with
myelodysplastic syndromes (MDS)/acute myeloid leukaemia (AML), as well as summarizing its pharmacological properties. The randomized, multicentre
Cancer and
Leukemia Group B 9221 trial compared the efficacy of subcutaneous
azacitidine with that of supportive care alone in patients with MDS fulfilling French-American-British (FAB) classification criteria. The overall response rate, the complete response rate and the complete plus partial response rate were significantly higher in patients receiving
azacitidine than in those receiving supportive care alone. The randomized, open-label, multicentre AZA-001 trial compared the efficacy of subcutaneous
azacitidine with that of conventional care in adults with higher-risk (i.e. International Prognostic Scoring System intermediate-2-risk or high-risk classification) MDS/AML. Prior to randomization, investigators preselected patients to the conventional care strategy considered most appropriate (i.e. best supportive care, low-dose
cytarabine or intensive
chemotherapy). The median duration of overall survival was significantly prolonged by 9.4 months in patients with higher-risk MDS receiving
azacitidine versus those receiving conventional care. The survival benefit seen with
azacitidine versus conventional care was maintained across various patient subgroups (e.g. in patients aged ≥75 years, in those who did not achieve complete remission and in patients with WHO-defined AML). The efficacy of subcutaneous or intravenous
azacitidine was also shown in a noncomparative trial in Japanese patients with MDS fulfilling FAB classification criteria, and registry programmes in various countries support the efficacy of
azacitidine in patients with MDS.
Azacitidine was generally well tolerated in patients with MDS, including in the elderly. Across trials, peripheral
cytopenias were the most commonly occurring adverse event in
azacitidine recipients, with gastrointestinal adverse events (e.g.
nausea,
vomiting and diarrhoea) and
injection-site reactions among the most commonly occurring non-haematological adverse events. In conclusion,
azacitidine is an important agent for use in the treatment of patients with MDS/AML.