High-dose methotrexate in ICU patients: a retrospective study

High-dose methotrexate (HD-MTX) is commonly used in the treatment of solid tumors and hematological malignancies. Severe toxicities are frequent, leading to organ dysfunction and death. Risk-benefit ratio of using HD-MTX in critically ill patients is unknown. This study aims to describe MTX-induced toxicities and to assess outcome in ICU patients. We conducted a retrospective single-center study conducted in a university hospital ICU between January 2002 and December 2018. Consecutive patients treated by HD-MTX were included.

33 patients (24 men and 9 women) aged 48 years [34-63], were included. B cell lymphoma had been diagnosed in 31 patients (Burkitt, n = 14; diffuse large B-cell lymphoma with CNS (central nervous system) involvement, n = 9; primary CNS lymphoma, n = 5) and T-cell lymphoma in two patients. Patients were mainly admitted for coma (n = 14; 42%) or acute kidney injury (n = 8; 24%). MTX was administered at a median dose of 6.1 g [5-14]. Fourteen patients had concomitant medication interacting with MTX. Median MTX clearance was 4 days [4-5]. Frequent MTX-related complication were mucositis (n = 21, 64%), diarrhea (n = 14, 44%) or hepatic failure (n = 15, 45%). During ICU stay, 11 patients experienced acute kidney injury (KDIGO stage 3 [2-3]). Two patients received carboxypeptidase and three underwent dialysis. Overall, 19 patients (57%) required mechanical ventilation, 10 (30%) vasopressors. Hospital mortality was 30% (n = 10). Cox model identified MTX concentration 24 h after administration higher than 4.6 µmol/L as associated with hospital mortality (HR 6.7; 95% CI 1.6-27.3).

To our knowledge, this is the first study assessing characteristics and outcome of critically ill patients receiving HD-MTX. MTX concentration at H24 was associated with hospital mortality. Despite underlying malignancy, ICU support of these patients was associated with a meaningful survival.