Incidence and Risk Factors for Breakthrough Invasive Mold Infections in Acute Myeloid Leukemia Patients Receiving Remission Induction Chemotherapy

BACKGROUND: Despite fungal prophylaxis, invasive mold infections (IMIs) are a significant cause of morbidity and mortality in patients with acute myeloid leukemia (AML) receiving remission induction chemotherapy. The choice of antifungal prophylaxis agent remains controversial, especially in the era of novel targeted therapies. We conducted a retrospective case–control study to determine the incidence of fungal infections and to identify risk factors associated with IMI. METHODS: Adult patients with AML receiving anti-Aspergillus prophylaxis were included to determine the incidence of IMI per 1000 prophylaxis-days. Patients without and with IMI were matched 2:1 based on the day of IMI diagnosis, and multivariable models using logistic regression were constructed to identify risk factors for IMI. RESULTS: Of the 162 included patients, 28 patients had a possible (n = 22), probable, or proven (n = 6) diagnosis of IMI. The incidence of proven or probable IMI per 1000 prophylaxis-days was not statistically different between anti-Aspergillus azoles and micafungin (1.6 vs 5.4, P = .11). The duration of prophylaxis with each agent did not predict IMI occurrence on regression analysis. Older age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.004–1.081; P = .03) and relapsed/refractory AML diagnosis (OR, 4.44; 95% CI, 1.56–12.64; P = .003) were associated with IMI on multivariable analysis. CONCLUSIONS: In cases that preclude use of anti-Aspergillus azoles for prophylaxis, micafungin 100 mg once daily may be considered; however, in older patients and those with relapsed/refractory disease, diligent monitoring for IMI is required, irrespective of the agent used for antifungal prophylaxis.