The impact of antimicrobial prophylaxis in morbidity and infections during azacitidine treatment.

The clinical consequences of the infectious events in patients receiving azacitidine are poorly documented. Likewise, the role of primary antimicrobial prophylaxis is unknown. In this retrospective, single-center study, we compare the impact of prophylaxis on the incidence of infection and morbidity in all consecutive higher-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) patients, during the first 4 azacitidine cycles. Seventy-six patients, corresponding to 283 azacitidine cycles, were studied. There were infectious events in 43% of the patients. Development of infections led to more hospital admissions, increased red blood cells and platelet requirements, and a delay in subsequent cycles. Median overall survival was comparable between patients with or without infections. In the multivariate analysis, a neutrophil count below 0.5 × 10 ⁹ /L (OR 12.5 [2.6-50]) and antimicrobial prophylaxis (OR 0.1 [0.02-04]) were independent factors for the development of infection. We conclude that infectious events have a significant impact in the early clinical course of azacitidine-treated patients by increasing hospital admissions and transfusion requirements. Antimicrobial prophylaxis may prevent infections, leading to a decreased need for supportive care in these patients with poor outcome.