Fusariosis in Patients With Hematologic Malignancies in the Era of Antifungal Prophylaxis

Invasive fusariosis (IF) is an uncommon but frequently fatal infection among patients with hematologic malignancies (HM). Despite widespread mould-active prophylaxis, breakthrough infections and treatment failures may occur. We aim to describe the clinical epidemiology, diagnostic approaches, antifungal management strategies, and outcomes of IF in the era of routine antifungal prophylaxis.

We conducted a retrospective study of all cancer patients diagnosed with IF at a tertiary cancer center that met probable/proven criteria for IF from 2015 to 2024. We collected data on demographics, oncologic history, diagnostics, therapy, and outcomes.

Twenty-two patients met criteria for proven IF. Most had acute myeloid leukemia (73%), and many underwent prior hematopoietic cell transplant (36%); nearly all were neutropenic (96%, median:48 days). Skin was the most common clinical site of infection (68%), followed by sino-pulmonary involvement (41%); fungemia occurred in 32%. Fever (77%) and skin nodules (64%) were frequent, while serum galactomannan was uniformly negative. Most common species complex was Fusarium fujikuroi. In our cohort, 82% occurred during antifungal prophylaxis, most often posaconazole. Minimum inhibitory concentrations were high for azoles and lower for amphotericin B and terbinafine. Antifungal regimens ranged from monotherapy to triple therapy. Overall mortality was 68%, of which 45% of deaths were attributed to IF. Mortality did not differ by antifungal regimen, species complexes, or presence of fungemia.

IF remains a life-threatening infection in patients with HM, often presenting as disseminated disease, despite prophylaxis. High azole MICs and the observed diversity of antifungal regimens highlight the ongoing uncertainty regarding optimal treatment and the need for prospective studies to define the role of combination therapy.