High-Dose Methotrexate in Pediatric Acute Lymphoblastic Leukemia: Predictors of Delayed Clearance and the Effect of Increased Hydration Rate on Methotrexate Clearance.

Objectives High-dose methotrexate (HDMTX) is an important chemotherapeutic agent in the treatment of many cancers. Identification of the predictors of poor clearance during HDMTX infusions could advance the introduction of improved supportive care to prevent toxicities and reduce hospital length of stay. The purpose of this study was to identify relationships between patient physical characteristics and HDMTX clearance in the treatment of pediatric acute lymphoblastic leukemia (ALL). At our hospital, patients who have delayed methotrexate (MTX) clearance during a cycle of HDMTX receive an increased rate of hydration with subsequent cycles. This increase in hydration rate was examined for its potential to mitigate predictors of poor clearance and to prevent nephrotoxicity. Methods This study retrospectively examined the treatment records of 87 pediatric patients diagnosed with ALL who were treated on or according to Children's Oncology Group (COG) protocols AALL0232, AALL0434, AALL1131, and AALL1231. Each patient received four cycles of HDMTX (5 g/m2 over 24 hours) at two-week intervals. Patients received either 125 ml/m2/hour (standard) or 200 ml/m2/hour (delayed clearance protocol) hydration before, with, and after each infusion. MTX levels taken at 24-, 42-, and 48-hour time points were used as an indirect measure of drug clearance. Two-tailed inference for ordinary least squares regression and both heteroskedastic and paired two-tailed t-tests were performed to identify physical characteristics associated with delayed MTX clearance and the effects of hydration rate on MTX clearance, respectively. Results Patient age and body surface area (BSA) were found to have statistically significant (p<0.05) positive associations with the serum MTX levels at 24, 42, and 48 hours in cycle 1. Age and BSA were significant only at the 24-hour time point in cycles 2 and 4. Weight alone was not associated with delayed MTX clearance. For patients who had delayed MTX clearance once and thus received the delayed clearance protocol in subsequent cycles, increasing the hydration rate from 125 to 200 ml/m2/hour was associated with a statistically significant decrease in average MTX levels as well as serum creatinine levels at the 24-, 42-, and 48-hour time points. Once patients with delayed clearance received the 200 ml/m2/hour rate of hydration, the history of prior poor clearance lost its predictive value for serum MTX levels and delayed clearance. Conclusions These results suggest that patient age and BSA are significant predictors of MTX clearance if all patients receive the same rate of hydration. Age and BSA affect the distribution phase of MTX kinetics, with downstream effects in the elimination phase. Increased hydration mitigates the effects of these physical characteristics on the elimination phase kinetics by improving renal elimination of MTX, causing a loss of significance of age and BSA as predictors of MTX levels in subsequent cycles at the 42- and 48-hour time points, but with less effect at 24 hours. Thus, hyperhydration regimens prior to cycle 1 of HDMTX could be considered for patients presenting with risk factors of advanced age or high BSA to avoid delayed clearance.

Chen AR ，Wang YM ，Lin M ，Kuo DJ ... -  《Cureus》

Extended duration of prehydration does not prevent nephrotoxicity or delayed drug elimination in high-dose methotrexate infusions: a prospectively randomized cross-over study.

Alkalized hydration is used as supportive care to prevent renal toxicity during infusions with high-dose methotrexate (HDMTX). In children with acute lymphoblastic leukemia (ALL), the hydration is commonly initiated 4 hours before start of the methotrexate (MTX) infusion. To test if longer duration of prehydration would prevent MTX-induced renal toxicity, we preformed a randomized cross-over study comparing 12-4 hours of hydration before the infusion of HDMTX. Children with ALL and non-Hodgkin lymphoma that were treated with infusions of HDMTX 5 or 8 g/m(2) were randomized to receive intravenous prehydration 12 or 4 hours before the first HDMTX infusion. Patients alternated between 12 and 4 hours of prehydration in the subsequent HDMTX infusions. Renal toxicity was defined as 50% increase in plasma creatinine after the HDMTX infusion. The plasma MTX concentration was measured during and after the HDMTX infusion to determine if the duration of prehydration would influence the systemic MTX clearance. A total of 47 patients (224 HDMTX infusions) with a median age of 4.9 years were included in the study. The duration of prehydration had no effect on MTX induced renal toxicity that occurred in 18.5% of all HDMTX 5 g/m(2) infusions and in 40.0% of all HDMTX 8 g/m(2) infusions. Similar the duration of prehydration had no impact on the systemic clearance of MTX. Extending prehydration beyond 4 hours does not reduce the risk of renal toxicity or delayed MTX clearance after infusions with HDMTX 5-8 g/m(2).

Mikkelsen TS ，Mamoudou AD ，Tuckuviene R ，Wehner PS ，Schroeder H ... -  《-》

Creatinine clearance rate and serum creatinine concentration are related to delayed methotrexate elimination in children with lymphoblastic malignancies.

Mao J ，Zhang L ，Shen H ，Tang Y ，Song H ，Zhao F ，Xu W ... -  《NEOPLASMA》

Improved Survival for Children and Young Adults With T-Lineage Acute Lymphoblastic Leukemia: Results From the Children's Oncology Group AALL0434 Methotrexate Randomization.

Winter SS ，Dunsmore KP ，Devidas M ，Wood BL ，Esiashvili N ，Chen Z ，Eisenberg N ，Briegel N ，Hayashi RJ ，Gastier-Foster JM ，Carroll AJ ，Heerema NA ，Asselin BL ，Gaynon PS ，Borowitz MJ ，Loh ML ，Rabin KR ，Raetz EA ，Zweidler-Mckay PA ，Winick NJ ，Carroll WL ，Hunger SP ... -  《-》

Plasma creatinine as predictor of delayed elimination of high-dose methotrexate in childhood acute lymphoblastic leukemia: A Danish population-based study.

Severely delayed elimination of methotrexate (MTX) is difficult to predict in patients treated with high-dose MTX (HD-MTX), but it may cause life-threatening toxicity. It has not been defined how an increase in plasma creatinine can be best used as a predictor for severely delayed MTX elimination, thus providing a guide for therapeutic interventions to minimize renal toxicity. Pharmacokinetic data were retrospectively collected on 218 Danish children with acute lymphoblastic leukemia treated with HD-MTX 5 or 8 g/m2 on the NOPHO2000 protocol. Moderately delayed MTX elimination was defined as 42-hour plasma MTX ≥ 4.0-9.9 μM, and severely delayed elimination was defined as 42-hour plasma MTX ≥ 10 μM. Median 42-hour plasma MTX was 0.61 μM (interquartile range, 0.4-1.06 μM). Of 1295 MTX infusions with 5 g/m2 (n = 140 patients) or 8 g/m2 (n = 78 patients), 5.1% were severely (1.5%) or moderately (3.6%) delayed. The risk of having delayed elimination was highest in the first of eight infusions with MTX 5 g/m² (7.4% vs 0.0 to 4.1% for subsequent MTX infusions) (P < 0.02). A 25 μM increase or a 1.5-fold increase in plasma creatinine within 36 hours from start of the MTX infusion had a sensitivity of 92% (95% CI, 82%-97%) and a specificity of 85% (95% CI, 83%-87%) for predicting 42-hour MTX ≥4.0 μM. A 25 μM increase or a 1.5-fold in plasma creatinine within 36 hours after start of an HD-MTX infusion can predict delayed MTX elimination, thus allowing intensification of hydration and alkalization to avoid further renal toxicity and promote the elimination of MTX.

Schmidt D ，Kristensen K ，Schroeder H ，Wehner PS ，Rosthøj S ，Heldrup J ，Damsgaard L ，Schmiegelow K ，Mikkelsen TS ... -  《-》