Delayed Elimination After High-dose Methotrexate in Pediatric Patients with Acute Lymphoblastic Leukemia and Non-Hodgkin Lymphoma

BACKGROUND: High doses of methotrexate (MTX) are often used in various chemotherapy protocols to treat acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL) in children, but its delayed elimination increases the occurrence of adverse events, such as bone marrow suppression. The aim of this study was to investigate the elimination of MTX at 24 and 48 hours. METHODS: We retrospectively analyzed electronic medical records of ALL or NHL pediatric patients who received 5 g/m² MTX infusion over 24 hours (between June, 2012 and July, 2018) at the Yonsei University Health System, Korea. The delayed elimination of MTX concentrations was assessed with 100 or 150 µM MTX at 24 hours, and 2 or 5 µM at 48 hours. RESULTS: Among the 85 MTX cycles administered, 23 cycles were classified in delayed elimination group, and 62 cycles showed normal elimination. At 24 hours, the delayed elimination group with MTX concentration > 100 µM showed higher percentage than group with MTX concentration < 100 µM (45.8% vs. 19.7%, p = 0.015). However, no differences were observed at 150 µM MTX (p = 0.66). At 48 hours, the delayed elimination was higher than the normal elimination at both concentration baselines (p < 0.001 at 2 µM, p = 0.024 at 5 µM). CONCLUSIONS: MTX concentrations greater than 100 µM show high probability of delayed elimination at 24 hours. When MTX levels are above normal, leucovorin and hydration regimens should be continued to prevent delayed elimination.

Posaconazole for Prophylaxis of Fungal Infection in Pediatric Patients with Acute Myeloid Leukemia undergoing Induction Chemotherapy

BACKGROUND: Posaconazole is a broad-spectrum triazole antifungal agent and the most recommended prophylactic antifungal agent for patients with acute myeloid leukemia (AML) undergoing induction chemotherapy. In this study, we evaluated the status and effectiveness of posaconazole as a prophylactic antifungal agent in pediatric patients receiving induction chemotherapy for AML. METHODS: We retrospectively reviewed the electronic medical records of 36 pediatric patients with AML (between January 2013 and September 2017) at the Yonsei University Health System. Invasive fungal disease (IFD) was assessed as the primary endpoint of prophylactic antifungal effect. The secondary endpoints were incidence of fever, persistent fever despite the use of broad-spectrum antibiotics for 72 h, alteration of antifungal agent, intensive care unit admission, and death within 100 days. RESULTS: Among the 36 patients, 18 patients used posaconazole, 12 were treated with suspension formula, and 6 of them were treated with tablets. Eighteen patients did not use antifungal agents prophylactically. The mean number of days of posaconazole administration was 26.8±16 days. IFD occurred in 2/18 (11.1%) patients in the no prophylaxis group and in 1/18 (5.6%) patients in the posaconazole group (p=0.49). CONCLUSION: Posaconazole is expected to be useful for the prevention of IFD in pediatric patients with AML undergoing induction chemotherapy. Prospective studies of the effectiveness of posaconazole prophylaxis should be conducted in more pediatric patients in the future.