Breakthrough invasive fungal infection in patients with myeloid malignancy receiving posaconazole tablet prophylaxis: clinical features, risk factors, and posaconazole profiles.

Posaconazole (PSC) delayed-release tablet prophylaxis is the standard of care for preventing invasive fungal infection (IFI) in patients with acute myeloid leukemia undergoing myelosuppressive chemotherapy. The clinical features, risk factors, and PSC profiles of breakthrough IFI (bIFI) in patients receiving PSC tablet prophylaxis were investigated. A single-center retrospective cohort study was conducted, including adult patients with myeloid malignancy who received prophylactic PSC tablets while undergoing chemotherapy from June 2016 to June 2021. Logistic regression analysis was used to identify risk factors for breakthrough IFI. A receiver operating characteristic curve was used to predict the relationship between PSC trough level at steady-state and breakthrough IFI. A total of 434 patients with myeloid malignancy who received PSC tablets were screened. Ten patients with bIFI were compared with 208 non-IFI patients. There were four proven and six probable IFI cases, nine due to Aspergillus and one due to Fusarium species. The bIFI patients had higher in-hospital mortality (30.0%) than the non-IFI patients (1.9%; P < 0.001). History of allogeneic hematopoietic stem cell transplantation (OR 6.27; 95% CI 1.63-24.09), prolonged neutropenia ≥ 28 days (OR 4.33; 95% CI 1.20-15.70), and low plasma PSC concentration < 0.7 μg/mL (OR 16.33; 95% CI 4.15-64.26) were risk factors for bIFI. The optimal cut-off value of plasma PSC concentration predicting bIFI was 0.765 μg/mL (sensitivity, 60.0%; specificity, 91.3%; area under the curve, 0.746). bIFI was not uncommon in patients with myeloid malignancy receiving PSC tablets prophylaxis and associated with poor outcomes. Therapeutic drug monitoring may still be necessary, even in patients receiving PSC tablets.