1735. Epidemiology of Invasive Fungal Infections During Induction Chemotherapy in Adults With Newly Diagnosed Acute Myeloid Leukemia Without Antifungal Prophylaxis: A Retrospective Cohort Study

BACKGROUND: While invasive fungal infections (IFIs) are common in patients with acute myeloid leukemia (AML) undergoing induction chemotherapy, little current data exist on the epidemiology of IFIs in this patient population given widespread use of antifungal prophylaxis. Because our institution does not administer antifungal prophylaxis, we are in a unique position to study the natural history of IFIs in these patients. METHODS: We evaluated the incidence of IFIs using established definitions in adults with AML undergoing induction chemotherapy at Stanford Health Care from 2012 to 2017. We also analyzed incidence of antifungal treatment, impact of IFI diagnosis on survival, and risk factors for IFI development. Patients were followed for up to 12 weeks after beginning induction chemotherapy. RESULTS: Of 488 patients analyzed, 243 were eligible for inclusion. The median age was 57 (interquartile range 45–65). Men composed 134 (55%) of the patients and 157 (65%) where white. Fifty-four (22%) had antecedent myelodysplastic syndrome; most received a “7 + 3” regimen involving cytarabine and an anthracycline. Thirty-one (13%) developed a proven or probable IFI; 104 (43%) developed a proven, probable, or possible IFI. Most IFIs were due to lower respiratory tract disease. Eighteen identified organisms were Candida, including six C. albicans. Eight organisms were mold, including four Aspergillus isolates (all but one A. fumigatus) and one isolate each of Fusarium solani, Rhizomucor, Rhizopus, and Scedosporium apiospermum/Pseudallescheria boydii. One hundred ninety patients (78%) received antifungals during their initial admission and 99 (46%) of patients surviving their initial admission were discharged on antifungals. Only 66.7% of patients with a proven or probable IFI survived through 12 weeks, compared with 92.2% of those without (P = 0.007). Baseline absolute neutrophil count ≤500 cells/μL and longer duration of neutropenia were significantly associated with development of proven or probable IFIs. CONCLUSION: Among patients receiving induction chemotherapy for AML, IFIs due to Candida and mold remain frequent absent antifungal prophylaxis and are associated with worse survival. Our findings support the use of antifungal prophylaxis in this patient population. DISCLOSURES: All authors: No reported disclosures.