High-dose methotrexate-induced nephrotoxicity in patients with osteosarcoma

A Case Report on Iatrogenic Methotrexate Toxicity

This case study studies the adverse effects of methotrexate toxicity as well as the importance of early recognition of the symptoms and signs of methotrexate toxicity. This study involves a 54-year-old female who accidentally took methotrexate in high doses for a period of five consecutively days. The patient had been diagnosed with mixed connective tissue disease and was being treated with methotrexate once weekly. However, she took 7.5 mg (three tablets) three times a day for five days instead of 15 mg once weekly in two divided doses. The patient immediately went to the ER but was asymptomatic and discharged after a CBC showed values within the normal range. The patient was then seen by her primary care physician and advised to return to the ER. At this time, the patient had mucocutaneous lesions and was complaining of oral and throat pain, and a repeat CBC demonstrated pancytopenia. The patient was admitted to the hospital for further management and treatment of methotrexate toxicity.

Phase 2 study of glucarpidase in patients with delayed methotrexate elimination after high-dose methotrexate therapy

PURPOSE

High-dose methotrexate therapy (HD-MTX) is a standard treatment for various malignant tumors, but approximately 1-10% of patients experience delayed MTX elimination (DME) that can induce organ damage. Glucarpidase can hydrolyze MTX and thereby lower the level of active MTX in the blood. A multicenter, open-label, phase II investigator-initiated trial (CPG2-PII study) was conducted to evaluate glucarpidase rescue therapy in Japanese patients who showed DME after HD-MTX treatment. To confirm the robustness of this therapy, further corporate-sponsored clinical trial (OP-07-001 study) was conducted.

METHODS

The primary endpoint in the CPG2-PII study was to evaluate the proportion of patients of the percentage clinical important reduction (CIR) as an indicator of MTX concentration, which can be managed with leucovorin and supportive care. The primary endpoint of the OP-07-001 study was to evaluate the decreasing rate of plasma MTX concentration at 20 min after glucarpidase administration from the baseline for four patients. Glucarpidase was administered at a dose of 50 U/kg for 15 and 4 patients, respectively in the two studies, and safety was analyzed for each of them.

RESULTS

The rate of CIR was 76.9% (95% confidence interval, 46.2-95.0%) in the CPG2-PII study. The median reduction rate of plasma MTX was 98.83% in the OP-07-001 study. Hypersensitivity, blood bilirubin increased, and headache for each patient were the only study drug-related events.

CONCLUSION

Glucarpidase showed an effect of reducing plasma MTX concentration in Japanese patients with DME as that observed in a previous US study, confirming its favorable safety and tolerability.

Dose-dependent renoprotective effect of vanillic acid on methotrexate-induced nephrotoxicity via its anti-apoptosis, antioxidant, and anti-inflammatory properties

Methotrexate-induced nephrotoxicity is a medical emergency which is associated with a variety of side effects. Vanillic acid (VA), as an antioxidant, removes free radical oxygen to protect cell defense. Therefore, this study investigated VA's beneficial effects on nephrotoxicity induced by methotrexate through its anti-apoptosis, antioxidant, and anti-inflammatory properties. Our study included five groups of male Wistar rats (n = 8): sham, MTX (Methotrexate) group: rats receiving methotrexate (20 mg/kg, intraperitoneally) on Day 2. Moreover, the remaining groups consisted of animals that received vanillic acid (25, 50, and 100 mg/kg, orally for seven days) plus MTX on the 2nd day. The rats were deeply anesthetized on the eighth day to obtain blood and renal tissue samples. The results showed that MTX can increase blood urea nitrogen and creatinine. However, VA (50 and 100 mg/kg) improved renal function as approved by histological findings. Compared with MTX-treated rats, VA enhanced the contents of total antioxidant capacity (TAC) and reduced renal malondialdehyde (MDA). Moreover, VA reduced mRNA expressions of caspase-3 and Bcl-2-associated x protein (Bax) and caused mRNA overexpression of the renal B-cell lymphoma-2 (Bcl-2), and Nrf-2 (Nuclear factor erythroid 2-related factor 2) compared to the MTX group. Also, VA administration significantly reduced inflammatory agents. Overall, VA protects the kidneys against methotrexate-induced nephrotoxicity via anti-apoptosis, antioxidant, and anti-inflammatory properties. Our results revealed that the most effective dose of VA was 100 mg/kg.

Nobiletin alleviates methotrexate-induced hepatorenal toxicity in rats

We investigated the possible ameliorative effects of nobiletin (NBL) against methotrexate (MTX)-induced hepatorenal toxicity in rats. Twenty-eight Wistar albino rats were randomly divided into four groups, namely: Control; MTX (administered 20 mg/kg MTX); MTX+NBL (administered 20 mg/kg MTX and 10 mg/kg NBL per day); and NBL (administered 10 mg/kg/day NBL). Histopathological, immunohistochemical and biochemical analyses were performed on the kidney and liver tissues of rats at the end of the study. MTX caused renal toxicity, as indicated by increases in malondialdehyde (MDA) and caspase-3, as well as decreases in reduced glutathione (GSH), glucose-6-phosphate dehydrogenase (G6PD), glutathione peroxidase (GPx), catalase (CAT) and B-cell lymphoma-2 (Bcl-2). MTX also caused hepatotoxicity, as indicated by increases in 8-hydroxy-2'-deoxyguanosine (8-OHdG), tumor necrosis factor alpha (TNF-α), MDA and caspase-3 and decrease in interleukin 10 (IL-10), GSH, total antioxidant capacity, GPx, G6PD, CAT and Bcl-2. MTX caused histopathological changes in kidney and liver tissues indicating tissue and cellular damage. Administration of NBL concurrently with methotrexate reduced oxidative stress, inflammatory and apoptotic signs, and prevented kidney and liver damage caused by methotrexate. We consider NBL has attenuating and ameliorating effects on methotrexate-induced hepatorenal toxicity.

External Evaluation of Population Pharmacokinetic Models for High-Dose Methotrexate in Adult Patients with Hematological Tumors

Currently, numerous population pharmacokinetic (popPK) models for methotrexate (MTX) have been published for estimating PK parameters and variability. However, it is unclear whether the accuracy of these models is sufficient for clinical application. The aim of this study is to evaluate published models and assess their predictive performance according to the standards of scientific research. A total of 237 samples from 74 adult patients who underwent high-dose MTX (HDMTX) treatment at Shanghai Changzheng Hospital were collected. The software package NONMEM was used to perform an external evaluation for each model, including prediction-based diagnosis, simulation-based diagnosis, and Bayesian forecasting. The simulation-based diagnosis includes normalized prediction distribution error (NPDE) and visual predictive check (VPC). Following screening, 7 candidate models suitable for external validation were identified for comparison. However, none of these models exhibited excellent predictive performance. Bayesian simulation results indicated that the prediction precision and accuracy of all models significantly improved when incorporating prior concentration information. The published popPK models for MTX exhibit significant differences in their predictive performance, and none of the models were able to accurately predict MTX concentrations in our data set. Therefore, before adopting any model in clinical practice, extensive evaluation should be conducted.

Diallyl trisulfide inhibits osteosarcoma 143B cell migration, invasion and EMT by inducing autophagy

Background

Diallyl trisulfide (DATS), a compound derived from garlic, has been demonstrated its anti-cancer properties. While it has been shown to inhibit the expression of epidermal growth factor receptor (EGFR) in various cancers, its effects on osteosarcoma (OS) cells remain unclear. This study aimed to investigate the impacts of DATS on OS cells growth, migration, invasion, epithelial-mesenchymal transition (EMT) and autophagy, as well as its underlying mechanisms which was involving in the EGFR/PI3K/AKT/mTOR pathway.

Methods

In this study, human osteosarcoma cells (143B) were treated with different concentrations of DATS (10, 50, 100 and 200 μM) for 24 and 48 h, respectively. Cell viability was measured using CCK8, the half lethal concentration was selected for the following experiments. Wound healing and transwell assays were performed to evaluate migration and invasion abilities, while flow cytometry was used to measure apoptosis. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blotting, and confocal imaging were employed to analyze the related mRNA and protein expression levels of epithelial-mesenchymal transition (EMT), EGFR/Phosphoinositide 3 kinase (PI3K)/AKT/Mammalian target of rapamycin (mTOR) signaling pathway and autophagy-related markers.

Results

DATS significantly inhibited proliferation, migration and EMT in osteosarcoma cells. Additionally, DATS promoted cell apoptosis and induced autophagy, which could be rescued by the autophagy inhibitor 3-methyladenine (3-MA). Moreover, DATS treatment led to the inactivation of the EGFR/PI3K/AKT/mTOR pathway in osteosarcoma cells.

Conclusions

This study demonstrated that DATS inhibited osteosarcoma cell growth, migration and EMT, but inducing apoptosis and autophagy. These effects were mediated by the inactivation of the EGFR/PI3K/AKT/mTOR signaling pathway. These findings suggested that DATS could serve as a potential therapeutic agent for osteosarcoma treatment.

Gut diversity and the resistome as biomarkers of febrile neutropenia outcome in paediatric oncology patients undergoing hematopoietic stem cell transplantation

The gut microbiota of paediatric oncology patients undergoing a conditioning regimen before hematopoietic stem cell transplantation is recently considered to play role in febrile neutropenia. Disruption of commensal microbiota and evolution of opportune pathogens community carrying a plethora of antibiotic-resistance genes play crucial role. However, the impact, predictive role and association of patient´s gut resistome in the course of the therapy is still to be elucidated. We analysed gut microbiota composition and resistome of 18 paediatric oncology patients undergoing hematopoietic stem cell transplantation, including 12 patients developing febrile neutropenia, hospitalized at The Bone Marrow Transplantation Unit of the National Institute of Children´s disease in Slovak Republic and healthy individuals (n = 14). Gut microbiome of stool samples obtained in 3 time points, before hematopoietic stem cell transplantation (n = 16), one week after hematopoietic stem cell transplantation (n = 16) and four weeks after hematopoietic stem cell transplantation (n = 14) was investigated using shotgun metagenome sequencing and bioinformatical analysis. We identified significant decrease in alpha-diversity and nine antibiotic-resistance genes msr(C), dfrG, erm(T), VanHAX, erm(B), aac(6)-aph(2), aph(3)-III, ant(6)-Ia and aac(6)-Ii, one week after hematopoietic stem cell transplantation associated with febrile neutropenia. Multidrug-resistant opportune pathogens of ESKAPE, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli found in the gut carried the significant subset of patient's resistome. Over 50% of patients treated with trimethoprim/sulfamethoxazole, piperacillin/tazobactam and amikacin carried antibiotic-resistance genes to applied treatment. The alpha diversity and the resistome of gut microbiota one week after hematopoietic stem cell transplantation is relevant predictor of febrile neutropenia outcome after hematopoietic stem cell transplantation. Furthermore, the interindividual diversity of multi-drug resistant opportunistic pathogens with variable portfolios of antibiotic-resistance genes indicates necessity of preventive, personalized approach.

A population pharmacokinetic model of methotrexate in Korean patients with haematologic malignancy

AIMS

This study was conducted to develop a population pharmacokinetic (PK) model of methotrexate in Korean patients with haematologic malignancy, identify factors affecting methotrexate PK, and propose an optimal dosage regimen for the Korean population.

METHODS

Data were retrospectively collected from 188 patients with acute leukaemia or non-Hodgkin's lymphoma who were admitted to Severance Hospital during the period from November 2005 to January 2016. Using demographic factors and laboratory results as potential covariates for PK parameters, model development was performed using NONMEM and optimal dosing regimens were developed using the final PK model.

RESULTS

A two-compartment model incorporating body weight via allometry best described the data, yielding typical parameter values of 25.09 L for central volume of distribution ( V 1 ), 17.65 L for peripheral volume of distribution ( V 2 ), 12.89 L/h for clearance (CL) and 0.655 L/h for inter-compartmental clearance in a 50 kg patient. Covariate analyses showed that, at the weight of 50 kg, CL decreased by 0.11 L/h for each 1-year increase in age above 14 years old and decreased 0.8-fold when serum creatinine level doubled, indicating the importance of age-specific dose individualization in methotrexate treatment. Volume of distribution at steady state derived from PK parameters (=  V 1  +  V 2 ) was 0.85 L/kg, which was similar to those in the Western or Chinese populations. Optimal doses simulated from the final model successfully produced the PK measures close to the target chosen.

CONCLUSIONS

The population PK model and optimal dosage regimens developed in this study can be used as a basis to achieve precision dosing in Korean patients with haematologic malignancy.

Dysregulation of the mRNA Expression of Human Renal Drug Transporters by Proinflammatory Cytokines in Primary Human Proximal Tubular Epithelial Cells

Proinflammatory cytokines, which are elevated during inflammation or infections, can affect drug pharmacokinetics (PK) due to the altered expression or activity of drug transporters and/or metabolizing enzymes. To date, such studies have focused on the effect of cytokines on the activity and/or mRNA expression of hepatic transporters and drug-metabolizing enzymes. However, many antibiotics and antivirals used to treat infections are cleared by renal transporters, including the basal organic cation transporter 2 (OCT2), organic anion transporters 1 and 3 (OAT1 and 3), the apical multidrug and toxin extrusion proteins 1 and 2-K (MATE1/2-K), and multidrug resistance-associated protein 2 and 4 (MRP2/4). Here, we determined the concentration-dependent effect of interleukin-6 (IL-6), IL-1β, tumor necrosis factor (TNF)-α, and interferon-γ (IFN-γ) on the mRNA expression of human renal transporters in freshly isolated primary human renal proximal tubular epithelial cells (PTECs, n = 3-5). PTECs were exposed to either a cocktail of cytokines, each at 0.01, 0.1, 1, or 10 ng/mL or individually at the same concentrations. Exposure to the cytokine cocktail for 48 h was found to significantly downregulate the mRNA expression, in a concentration-dependent manner, of OCT2, the organic anion transporting polypeptides 4C1 (OATP4C1), OAT4, MATE2-K, P-glycoprotein (P-gp), and MRP2 and upregulate the mRNA expression of the organic cation/carnitine transporter 1 (OCTN1) and MRP3. OAT1 and OAT3 also appeared to be significantly downregulated but only at 0.1 and 10 ng/mL, respectively, without a clear concentration-dependent trend. Among the cytokines, IL-1β appeared to be the most potent at down- and upregulating the mRNA expression of the transporters. Taken together, our results demonstrate for the first time that proinflammatory cytokines transcriptionally dysregulate renal drug transporters in PTECs. Such dysregulation could potentially translate into changes in transporter protein abundance or activity and alter renal transporter-mediated drug PK during inflammation or infections.

Vinpocetine mitigates methotrexate-induced duodenal intoxication by modulating NF-κB, JAK1/STAT-3, and RIPK1/RIPK3/MLKL signals

OBJECTIVES

Methotrexate (MTX) is an antimetabolite agent widely used to manage a variety of tumors and autoimmune diseases. Nonetheless, MTX-induced intestinal intoxication is a serious adverse effect limiting its clinical utility. Inflammation and oxidative stress are possible mechanisms for MTX-induced intestinal toxicity. Vinpocetine (VNP) is a derivative of the alkaloid vincamine with potent anti-inflammatory and antioxidant effects. The current study investigated the protective intestinal impact of VNP in attenuating MTX-induced intestinal intoxication in rats.

MATERIALS AND METHODS

VNP was administered orally in a dose of 20 mg/kg, while MTX was injected intraperitoneal in a dose of 20 mg/kg.

RESULTS

VNP administration attenuated drastic histological changes induced by MTX and preserved both normal villus and crypt histology. VNP significantly attenuated oxidative injury by upregulating intestinal Nrf2 and HO-1 expression. VNP attenuated inflammation by reducing MPO, NO2-, TNF-α, and IL-1β levels mediated by downregulating NF-κB, NDAPH-oxidase, IRF3, p-JAK-1, and p-STAT-3 expressions. Moreover, VNP potently counteracted intestinal necroptosis by effectively downregulating RIPK1, RIPK3, MLKL, and caspase-8 proteins.

CONCLUSION

Therefore, VNP may represent a promising approach that can attenuate intestinal toxicity in patients receiving MTX.

A Delphi study to determine the epidemiology and clinical management of patients treated with HDMTX who develop methotrexate (MTX) delayed elimination in France, Germany, Italy, and the UK

Introduction

High-dose methotrexate (HDMTX) is administered for the treatment of some malignancies. Serious complications after the administration of HDMTX are rare, but occasionally MTX may precipitate in the renal tubes causing a delayed elimination leading to renal, multiorgan toxicities and to life-threatening complications. This study aims to estimate the incidence and clinical management of delayed MTX elimination in France, Germany, Italy, and the UK.

Methods

Twelve haemato-oncology and pediatric oncology clinical experts from leading European hospitals participated in the study. A two-round Delphi methodology was used to gather data on different variables relevant to evaluate the HDMTX induced-toxicity impact. For quantitative data, median and interquartile ranges were calculated. Data on prevalence was calculated considering the number of patients in each hospital and the population they cover, and then, extrapolated to the country population.

Results

The total number of patients treated annually with HDMTX in France, Germany, Italy, and the UK is estimated in 7155. Of these, 16% are estimated to develop delayed MTX elimination and around 9% may develop HDMTX-induced acute kidney injury (AKI). Leucovorin, hyperhydration and urine alkalinization are applied to prevent MTX toxicity and precipitation whilst glucarpidase, hemofiltration and hemodialysis are being used for persisting toxic MTX serum levels. Grade 3 systemic toxicities are common in these patients, hematologic and gastrointestinal being the most common ones.

Conclusions

This report provides expert clinical practice experience and opinion of the incidence and management of HDMTX-delayed elimination in France, Germany, Italy and the UK, thereby contributing to the evidence available on this relevant medical condition which can be life-threatening.

Modulatory effect of amifostine (WR-1065) against genotoxicity and oxidative stress induced by methotrexate in human umbilical vein endothelial cells (HUVECs)

Amifostine is used in chemotherapy and radiotherapy as a cytoprotective adjuvant alongside DNA-binding chemotherapeutic agents. It functions by reducing free radicals and detoxifying harmful metabolites. Methotrexate, as an antimetabolite drug has been considered for treating various cancers and autoimmune diseases. However, the cytotoxic effects of methotrexate extend beyond tumor cells to crucial organs, including the heart. This study applied the HUVEC cell line as a reference in vitro model for researching the characteristics of vascular endothelium and cardiotoxicity. The current study aimed to assess amifostine's potential cytoprotective properties against methotrexate-induced cellular damage. Cytotoxicity was measured using the MTT assay. Apoptotic rates were evaluated by Annexin V-FITC/PI staining via flow cytometry. The genoprotective effect of amifostine was determined using the comet assay. Cells were exposed to various amifostine doses (10-200 μg/mL) and methotrexate (2.5 μM) in pretreatment culture condition. Methotrexate at 2.5 μM revealed cytotoxicity, apoptosis, oxidative stress and genotoxicity while highlighting amifostine's cyto/geno protective properties on HUVECs. Amifostine significantly decreased the levels of ROS and LPO while preserving the status of GSH and SOD activity. Furthermore, it inhibited genotoxicity (tail length, %DNA in tail, and tail moment) in the comet assay. Amifostine markedly attenuated methotrexate-induced apoptotic cell death (early and late apoptotic rates). These findings convey that amifostine can operate as a cytoprotectant agent.

Use of glucarpidase (carboxypeptidase-G2) in pediatric cancer patients: 11-year experience of a tertiary center

Methotrexate is an essential drug in the treatment of childhood cancer that is not exempt from toxicities. Glucarpidase is a drug used to reduce the toxic concentration of plasma methotrexate in patients with delayed elimination or at risk of toxicity. We describe the characteristics of a cohort of pediatric patients that received glucarpidase and analyze its role in the treatment of toxicity induced by high doses of methotrexate (HDMTX). Retrospective observational study of all pediatric cancer patients who received glucarpidase between 2012 and 2022 at a single center. Fifteen patients were treated with a single dose of glucarpidase, eleven of them presented with acute lymphoblastic leukemia and received HDMTX at 5 g/m2 in 24-hour infusion. In eight patients, glucarpidase was administered during the first cycle of HDMTX. The indication in thirteen cases was acute renal failure with delayed elimination of plasma methotrexate. The median maximum creatinine was 1.22 mg/dl (0.68 2.01 mg/dl), with a median increase over its baseline level of 313%. All patients normalized renal function after glucarpidase administration, with a median methotrexate excretion time of 193 hours (42-312 hours). No grade ≥2 adverse events derived from carboxypeptidase administration. Eleven patients received new doses of HDMTX in subsequent cycles, without new episodes of serious toxicity. The use of glucarpidase is effective and safe in the treatment of acute renal failure and methotrexate elimination delay in pediatric cancer patients. Further HDMTX doses may be prescribed without additional toxicities.

Osteosarcoma in Pediatric and Adult Populations: Are Adults Just Big Kids?

Malignant bone tumors are commonly classified as pediatric or adolescent malignancies, and clinical trials for these diseases have generally focused on these populations. Of primary bone cancers, osteosarcoma is among the most common. Osteosarcoma has a bimodal age distribution, with the first peak occurring in patients from 10 to 14 years old, and the second peak occurring in patients older than 65, with about 25% of cases occurring in adults between 20 and 59 years old. Notably, adult osteosarcoma patients have worse outcomes than their pediatric counterparts. It remains unclear whether age itself is a poor prognostic factor, or if inherent differences in tumor biology exist between age groups. Despite these unknowns, current treatment strategies for adults are largely extrapolated from pediatric studies since the majority of clinical trials for osteosarcoma treatments are based on younger patient populations. In light of the different prognoses observed in pediatric and adult osteosarcoma, we summarize the current understanding of the molecular etiology of osteosarcoma and how it may differ between age groups, hypothesizing why adult patients have worse outcomes compared to children.

Metabolomic profiling reveals the mechanisms underlying the nephrotoxicity of methotrexate in children with acute lymphoblastic leukemia

BACKGROUND

Methotrexate is widely recommended as a first-line treatment for the intensive systemic and consolidation phases of childhood acute lymphoblastic leukemia. However, methotrexate-induced nephrotoxicity is a severe adverse reaction, of which the mechanisms remain unclear.

METHODS

An untargeted metabolomics analysis of serum from childhood acute lymphoblastic leukemia patients with delayed methotrexate excretion, with or without acute kidney injury, was performed to identify altered metabolites and metabolic pathways. An independent external validation cohort and in vitro HK-2 cell assays further verified the candidate metabolites, and explored the mechanisms underlying the nephrotoxicity of methotrexate.

RESULTS

Four metabolites showed significant differences between normal excretion and delayed excretion, seven metabolites reflected the differences between groups with or without acute kidney injury, and six pathways were finally enriched. In particular, oxidized glutathione was confirmed as a candidate metabolite involved in the toxicity of methotrexate. We further explored the role of glutathione deprivation-induced ferroptosis on methotrexate cytotoxicity, and it was found that methotrexate overload significantly reduced cell viability, triggered reactive oxygen species and intracellular Fe2+ accumulation, and altered the expression of ferroptosis-related proteins in HK-2 cells. These methotrexate-induced changes were alleviated or reversed by the administration of a ferroptosis inhibitor, further suggesting that ferroptosis promoted methotrexate-induced cytotoxicity in HK-2 cells.

CONCLUSIONS

Our findings revealed complex metabolomic profiles and provided novel insights into the mechanism by which ferroptosis contributes to the nephrotoxic effects of methotrexate.

Chapter 1: Evaluation of kidney function in patients undergoing anticancer drug therapy, from clinical practice guidelines for the management of kidney injury during anticancer drug therapy 2022

The prevalence of CKD may be higher in patients with cancer than in those without due to the addition of cancer-specific risk factors to those already present for CKD. In this review, we describe the evaluation of kidney function in patients undergoing anticancer drug therapy. When anticancer drug therapy is administered, kidney function is evaluated to (1) set the dose of renally excretable drugs, (2) detect kidney disease associated with the cancer and its treatment, and (3) obtain baseline values for long-term monitoring. Owing to some requirements for use in clinical practice, a GFR estimation method such as the Cockcroft-Gault, MDRD, CKD-EPI, and the Japanese Society of Nephrology's GFR estimation formula has been developed that is simple, inexpensive, and provides rapid results. However, an important clinical question is whether they can be used as a method of GFR evaluation in patients with cancer. When designing a drug dosing regimen in consideration of kidney function, it is important to make a comprehensive judgment, recognizing that there are limitations regardless of which estimation formula is used or if GFR is directly measured. Although CTCAEs are commonly used as criteria for evaluating kidney disease-related adverse events that occur during anticancer drug therapy, a specialized approach using KDIGO criteria or other criteria is required when nephrologists intervene in treatment. Each drug is associated with the different disorders related to the kidney. And various risk factors for kidney disease associated with each anticancer drug therapy.

The use of glucarpidase as a rescue therapy for high dose methotrexate toxicity - a review of pharmacological and clinical data

INTRODUCTION

This review aims to summarize recent data on the pharmacodynamic, pharmacokinetic, and safety of glucarpidase. This is an enzymatic agent that catalyzes the conversion of methotrexate (MTX) into inactive metabolites. Glucarpidase is used to manage high-dose MTX (HDMTX) toxic plasma concentration, especially in patients with impaired renal function.

AREAS COVERED

In this review, studies on glucarpidase clinical efficacy as a therapeutic option for patients suffering from MTX kidney toxicity were presented. Pharmacodynamic and pharmacokinetic properties of glucarpidase were included. Moreover, potential interactions and safety issues were discussed.

EXPERT OPINION

The use of glucarpidase is an effective therapeutic strategy in both adults and children treated with high doses of MTX for various types of cancer who have developed acute renal failure. Glucarpidase causes MTX to be converted to nontoxic metabolites and accelerates the time for its complete elimination. After administration of glucarpidase, it is possible to resume HDMTX.

Pediatric cancer care management during the COVID-19 pandemic: a review of the literature and a single-centre real-life experience of an Italian pediatric oncology unit

INTRODUCTION

The severe acute respiratory syndrome coronavirus-2 pandemic significantly affected clinical practice, also in pediatric oncology units. Cancer patients needed to be treated with an adequate dose density despite the SARS-CoV-2 infection, balancing risks of developing severe COVID-19 disease.

AREAS COVERED

Although the pandemic spread worldwide, the prevalence of affected children was low. The percentage of children with severe illness was approximately 1-6%. Pediatric cancer patients represent a prototype of a previously healthy immune system that is hampered by the tumor itself and treatments, such as chemotherapy and steroids. Through a review of the literature, we reported the immunological basis of the response to SARS-CoV-2 infection, the existing antiviral treatments used in pediatric cancer patients, and the importance of vaccination. In conclusion, we reported the real-life experience of our pediatric oncology unit during the pandemic period.

EXPERT OPINION

Starting from the data available in literature, and our experience, showing the rarity of severe COVID-19 disease in pediatric patients with solid tumors, we recommend carefully tailoring all the oncological treatments (chemotherapy/targeted therapy/stem cell transplantation/radiotherapy). The aim is the preservation of the treatment's timing, balanced with an evaluation of possible severe COVID-19 disease.

Rescue Therapies for AKI in Onconephrology: Rasburicase and Glucarpidase

Tumor lysis syndrome (TLS) and high-dose methotrexate (HD MTX) toxicity can present with potentially severe complications, including acute kidney injury, in patients with malignancy. Guidelines for using rasburicase and glucarpidase as rescue therapies for TLS and HD MTX toxicity, respectively, are widely used by clinicians intending to mitigate organ toxicity and decrease morbidity and mortality as a consequence of cancer therapy. This review discusses the pathogenesis of TLS and HD MTX-associated toxicity, to understand the mechanism of action of these therapeutic agents and to review the currently available evidence supporting their use.

Apocynin abrogates methotrexate-induced nephrotoxicity: role of TLR4/NF-κB-p65/p38-MAPK, IL-6/STAT-3, PPAR-γ, and SIRT1/FOXO3 signaling pathways

The present study was designed to evaluate the potential renoprotective impacts of apocynin (APC) against nephrotoxicity induced by methotrexate (MTX) administration. To fulfill this aim, rats were allocated into four groups: control; APC (100 mg/kg/day; orally); MTX (20 mg/kg; single intraperitoneal dose at the end of the 5th day of the experiment); and APC +MTX (APC was given orally for 5 days before and 5 days after induction of renal toxicity by MTX). On the 11th day, samples were collected to estimate kidney function biomarkers, oxidative stress, pro-inflammatory cytokines, and other molecular targets. Compared to the MTX control group, treatment with APC significantly decreased urea, creatinine, and KIM-1 levels and improved kidney histological alterations. Furthermore, APC restored oxidant/antioxidant balance, as evidenced by a remarkable alleviation of MDA, GSH, SOD, and MPO levels. Additionally, the iNOS, NO, p-NF-κB-p65, Ace-NF-κB-p65, TLR4, p-p38-MAPK, p-JAK1, and p-STAT-3 expressions were reduced, while the IκBα, PPAR-γ, SIRT1, and FOXO3 expressions were significantly increased. In NRK-52E cells, MTX-induced cytotoxicity was protected by APC in a concentration-dependent manner. In addition, increased expression of p-STAT-3 and p-JAK1/2 levels were reduced in MTX-treated NRK-52E cells by APC. The in vitro experiments revealed that APC-protected MTX-mediated renal tubular epithelial cells were damaged by inhibiting the JAK/STAT3 pathway. Besides, our in vivo and in vitro results were confirmed by predicting computational pharmacology results using molecular docking and network pharmacology analysis. In conclusion, our findings proved that APC could be a good candidate for MTX-induced renal damage due to its strong antioxidative and anti-inflammatory bioactivities.

Melatonin protects against methotrexate hepatotoxicity in young rats: Impact of PI3K/Akt/mTOR signaling

With the improvement in children's acute lymphoblastic leukemia (ALL) care, the survival rate in children ALL has improved much. Methotrexate (MTX) plays an essential role in the success of children's ALL treatment. Since hepatotoxicity is commonly reported in individuals treated with intravenous or oral MTX, our study further examined the hepatic effect following intrathecal MTX treatment, which is an essential treatment for leukemia patients. Specifically, we examined the pathogenesis of MTX hepatotoxicity in young rats and explored the impact of melatonin treatment in protection against MTX hepatotoxicity. Successfully, we found that melatonin was able to protect against MTX hepatotoxicity.

Nephrotoxicity associated with anticancer agents: perspective on onconephrology from nephrologists

Nephrotoxicity is one of the most important complications in cancer patients. In particular, acute kidney injury (AKI) is known to be associated with discontinuing effective oncological treatments, longer hospitalizations, increased costs, and a higher risk of death. In addition to acute kidney injury, clinical signs associated with nephrotoxicity during treatment with anticancer agents include chronic kidney disease, proteinuria, hypertension, electrolyte abnormalities, and other characteristic manifestations. Many of these signs are caused both by cancer treatment as well as by cancer itself. Therefore, it is important to carefully recognize whether the underlying causes of renal impairment in cancer patients are cancer-related, treatment-related, or both. This review describes the epidemiology and pathophysiology of anticancer agent-induced acute kidney injury, proteinuria, hypertension, and other characteristic manifestations.

Establishment, Maintenance, and Performance of the Cooperative Osteosarcoma Study Group (COSS)

INTRODUCTION

Osteosarcoma treatment has benefitted greatly from collaborative research. This paper describes the history and accomplishments of the Cooperative Osteosarcoma Study Group (COSS), mainly dedicated to clinical questions, as well as remaining challenges.

MATERIALS AND METHODS

Narrative review of over four decades of uninterrupted collaboration within the multi-national German-Austrian-Swiss COSS group.

RESULTS

Since its very first prospective osteosarcoma trial starting in 1977, COSS has continuously been able to provide high-level evidence on various tumor- and treatment-related questions. This includes both the cohort of patients enrolled into prospective trials as well as those patients excluded from them for various reasons, followed in a prospective registry. Well over one hundred disease-related publications attest to the group's impact on the field. Despite these accomplishments, challenging problems remain.

DISCUSSION

Collaborative research within a multi-national study group resulted in better definitions of important aspects of the most common bone tumor, osteosarcoma, and its treatments. Important challenges continue to persist.

Acute Kidney Injury with SARS-CoV-2 Infection in Pediatric Patients Receiving High-Dose Methotrexate Chemotherapy: A Report of Three Cases

BACKGROUND

Methotrexate is renally excreted. HDMTX (high dose-methotrexate)-induced acute kidney injury (AKI) is a non-oliguric decrease in glomerular filtration rate (GFR) heralded by an acute rise in serum creatinine. Moreover, AKI is also a frequent complication of COVID-19. Among our patients treated with HDMTX, some of these developed AKI during SARS-CoV-2 infection. Therefore, we wondered whether our patients' kidney failure might have been triggered by their underlying SARS-CoV-2 positivity.

METHODS

Data were collected from the database at the Pediatric Oncology Unit of the Istituto Nazionale dei Tumori in Milan (Italy) regarding patients who matched the following selective criteria: (a) treatment with HDMTX during the pandemic period; (b) SARS-CoV-2 infection during the treatment; (c) development of AKI during HDMTX treatment and SARS-CoV-2 infection.

RESULTS

From March 2020 to March 2022, a total of 23 patients were treated with HDMTX; 3 patients were treated with HDMTX during SARS-CoV-2 infection and all 3 developed AKI.

CONCLUSIONS

Clinical manifestations associated with this virus are many, so we are not yet able to lower our guard and rule out this infection as a cause of clinical manifestations with any certainty.

Insights from a pharmacometric analysis of HDMTX in adults with cancer: Clinically relevant covariates for application in precision dosing

AIMS

High-dose methotrexate (HDMTX) is an essential part of the treatment of several adult and paediatric malignancies. Despite meticulous supportive care during HDMTX administration, severe toxicities, including acute kidney injury (AKI), may occur contributing to patient morbidity. Population pharmacokinetics provide a powerful tool to predict time to clear HDMTX and adjust subsequent doses. We sought to develop and validate pharmacokinetic models for HDMTX in adults with diverse malignancies and to relate systemic exposure with the occurrence of severe toxicity.

METHODS

Anonymized, de-identified data were provided from 101 US oncology practices that participate in the Guardian Research Network, a non-profit clinical research consortium. Modelled variables included clinical, laboratory, demographic and pharmacological data. Population pharmacokinetic analysis was performed by means of nonlinear mixed effects modelling using MonolixSuite.

RESULTS

A total of 693 HDMTX courses from 243 adults were analysed, of which 62 courses (8.8%) were associated with stage 2/3 acute kidney injury (43 stage 2, 19 stage 3). A three-compartment model adequately fitted the data. Time-dependent serum creatinine, baseline serum albumin and allometrically scaled bodyweight were clinically significant covariates related to methotrexate clearance. External evaluation confirmed a satisfactory predictive performance of the model in adults receiving HDMTX. Dose-normalized methotrexate concentration at 24 and 48 hours correlated with AKI incidence.

CONCLUSION

We developed a population pharmacometric model that considers weight, albumin and time-dependent creatinine that can be used to guide supportive care in adult patients with delayed HDMTX elimination.

Paullinia cupana seed extract ameliorated methotrexate-induced testicular dysfunction through the regulation of antioxidants, inflammatory, apoptosis/anti-apoptosis, and steroidogenesis-associated genes

Methotrexate (MXT) is a medication used for cancer and rheumatoid treatment with severe organs toxicity as a side effect. Paullinia cupana (Guarana) is a plant with pleiotropic functions used to overcome the side effects of some chemotherapeutic medications. Current study aimed to examine the possible protective effect of guarana against oxidative stress induced by a single dose of MTX in testis. Forty male mice were divided into 4 groups (8 weeks old; 30 g weight), 1st group is negative control. The 2nd group is positive intoxicated group, received a single dose of MTX intraperitoneally (IP; 20 mg/kg BW in saline) on day 7. The 3rd group received guarana seed extract orally (300 mg/kg BW daily) for 12 days. The protective group was given guarana seed extract orally for 1 week, then on day 7 injected with MTX, and continued with guarana for extra 5 days. Blood was taken for biochemical measurement (hormones, antioxidants, cytokines, and oxidative stress biomarkers). Testicular tissues were taken for gene quantification (qRT-PCR), testicular oxidative stress activity (malondialdehyde; MDA, and SOD) and comet assay (sperm DNA damage), and histopathological changes at the end of experimental design. MTX intoxication caused a decrease in testicular SOD, GSH, and catalase and an increase in serum and tissue levels of MDA. Biomarkers of oxidative stress were increased by MTX intoxication, and were ameliorated by guarana administration to MTX-intoxicated mice. Guarana prevented the increase in IL-1β and IL-6 levels compared to mice intoxicated with MTX alone. MTX upregulated the expression of caspase-3 and downregulated Bcl-2 expression using qRT-PCR analysis. These negative impacts of MTX were protected by guarana pre-administration. MTX decreased reproductive hormones and altered spermogram parameters (sperm concentration and motility, and percentage of live and dead sperms). In addition, the mRNA expression of steroidogenesis-associated genes, such cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and 17β hydroxyl steroid dehydrogenase (17β-HSD) was downregulated in the MTX-treated group, all were prevented by guarana administration. The sperm DNA damage revealed by a comet assay was increased in MTX group and was reversed to control levels by guarana supplementation. Finally, testis histology of MTX-group showed marked spermatocytes vacuolization and a decrease in spermatogenesis. Guarana administration abrogated histopathological changes reported in the Leydig cells and testicular tissues. In conclusion, guarana has the potential as a supplement medication to antagonize testicular oxidative stress induced by methotrexate.

Glucarpidase for Treating Adults with Delayed Methotrexate Elimination Due to Impaired Renal Function: An Economic Simulation Analysis

Background

Glucarpidase is indicated for treating delayed methotrexate (MTX) elimination due to impaired renal function. Although glucarpidase is capable of rapidly eliminating MTX independent of renal clearance, its cost can be perceived as a barrier to use. However, no published economic analyses have evaluated glucarpidase relative to comparable treatments.

Purpose

To assess the economic value of glucarpidase for treating adult patients in the United States (US) who experience delayed MTX elimination due to impaired renal function.

Methods

A decision tree model was developed to assess the economic value of glucarpidase. The short-term inpatient management of patients as well as long-term survival were simulated. Costs associated with the use of glucarpidase were compared against other methods for treating delayed MTX elimination due to impaired renal function under two scenarios: current practice (ie, mix of timely/delayed use of glucarpidase, hemodialysis, or supportive care [SC] alone) as compared with proposed practice (ie, timely glucarpidase administration within 60 hours for all eligible patients). Hypothetical practical scenarios for US institutions were also considered.

Results

For adult patients with delayed MTX elimination, proposed practice as compared to current practice was associated with an increased cost of $20,024 per patient, not considering any incremental reimbursement associated with glucarpidase administration. Importantly, early treatment with glucarpidase, within 60 hours, was shown to be less expensive per patient than delayed glucarpidase treatment or treating with hemodialysis, but more expensive than SC alone. However, proposed practice was associated with multiple clinical benefits, including shorter hospital length of stay. For hypothetical practical scenarios, minimal shifts in treatment patterns had minimal cost impacts.

Conclusion

Treatment of all eligible patients with glucarpidase within 60 hours was associated with an increased cost per patient (relative to current practice) but substantial improvements in clinical outcomes. Timely glucarpidase use was less expensive than delayed glucarpidase or hemodialysis.

Successful Treatment of Central Nervous System Post-Transplant Lymphoproliferative Disease With a Reduced Dose of High-Dose Methotrexate

Post-transplant lymphoproliferative disease (PTLD) is a complication of solid organ and hematopoietic stem cell transplantation that occurs as a result of immunosuppression. PTLD isolated to the central nervous system (CNS) is a rare disease and it presents with nonspecific signs and symptoms. Optimal therapy guidelines have not yet been established for CNS PTLD. Here, we report a case of successful treatment of CNS PTLD in an adult female following two subsequent kidney transplants. Initial management was with immunosuppression reduction and a trial of rituximab. There were concerns regarding using methotrexate (MTX) given the patient's fragile transplant status. Magnetic resonance imaging of the brain following four cycles of rituximab revealed the progression of the disease. Subsequently, high-dose MTX (HD-MTX) was considered within the constraints of potential kidney toxicities given her transplant status and chronic kidney disease. Potential toxicities from other therapies, such as brain radiation, also factored into the final decision. The patient was treated with one cycle of a combination of rituximab and HD-MTX 1 g/m². The patient tolerated HD-MTX and did not have evidence of renal toxicity in laboratory studies. Following that, she was started on a reduced dose of HD-MTX at 2 g/m² every two weeks instead of the higher MTX dose range of 3.5 to 8 g/m², which was a shared decision with the patient and nephrology after weighing the risk of kidney dysfunction with the possibility of a less than optimal response with regards to her lymphoma. She was followed with a magnetic resonance imaging of the brain, which demonstrated a complete response after four cycles. Further consolidation treatments with HD-MTX 2 g/m² every four weeks were administered to complete one year of treatment. Following the completion of chemotherapy, the patient was able to achieve and maintain a complete response without affecting her kidney function. She continues to do well one year following treatment. This case highlights the significance of tailoring therapy to each individual based on their comorbidities and clinical response, as well as the possible merit in exploring the use of a reduced dose of HD-MTX in the treatment of CNS PTLD in patients at high risk for renal toxicity.

High-Dose Methotrexate in Patients With Lymphoma: Predictors of a Complicated Course

PURPOSE

High-dose methotrexate (HDMTX; > 500 mg/m²) is an important component of lymphoma therapy. Serum MTX monitoring at 48 hours is the standard approach to identify those at increased risk of developing MTX toxicity. Our aim was to characterize the incidence of complications and their association with MTX levels.

METHODS

A retrospective review of our institutional electronic medical record was conducted to identify patients with lymphoma who received HDMTX between January 1, 2002, and December 31, 2018. We characterized the incidence of acute kidney injury (AKI), intensive care unit (ICU) admission, length of hospital stay (LOS), and 30-day mortality across 48-hour MTX levels. To establish an association between 48-hour MTX levels and the complications listed, we performed chi-square analysis for dichotomous variables and Kruskal-Wallis for nonparametric data. Receiver operator characteristic curve analysis was performed to identify the MTX level where AKI grade ≥ 2 was more likely. Multivariate logistic regression analysis was performed to identify risk factors for this MTX level.

RESULTS

We identified 642 patients with 2,804 cycles of HDMTX. The incidence of AKI was 19.1% with AKI grade ≥ 2 making up 21% of cases. Rates of AKI, ICU admission, and 30-day mortality are associated with elevated 48-hour MTX levels. There was a significant increase in median LOS with elevated MTX levels (P < .001). Receiver operator characteristic curve analysis for AKI grade ≥ 2 demonstrated a 48-hour MTX level threshold of 1.28 μmol/L. Multivariate logistic regression analysis revealed age, male sex, elevated body surface area, higher MTX dose, monotherapy, and first cycle as independent factors.

CONCLUSION

Elevated MTX levels are associated with a significant increased rate of AKI, ICU admission, prolonged LOS, and 30-day mortality. Elevated 48-hour MTX levels, particularly > 1.28 μmol/L, should alert clinicians for complications and to initiate measures to reduce MTX levels.

The Role of Single Nucleotide Polymorphisms in Transporter Proteins and the Folate Metabolism Pathway in Delayed Methotrexate Excretion: A Case Report and Literature Review

High-dose methotrexate (HDMTX) is a pivotal component of the chemotherapeutic regimens of osteosarcoma. However, the use of HDMTX is limited by an increased risk of dose-dependent toxicity. It is thought that the plasma levels and therapy-related toxicity of MTX could be associated with single nucleotide polymorphisms (SNPs) within MTX metabolism pathway genes. Here, we report a case of a paediatric osteosarcoma girl with delayed MTX excretion who was successfully managed using supportive measures and continuous veno-venous haemodiafiltration. We further identified the cause that could account for delayed elimination by genotyping analysis. The results showed that variations have been found in SLCO1B1, SLC19A1, ABCB1 and MTHFR, all those were reported to have a strong association with delayed elimination of MTX in clinical studies. After comprehensive consideration of genotype and clinical phenotype, the second course of HDMTX was administered to this patient at a half reduced dose. We also performed a literature review to summarize the pharmacogenetic factors that influence HDMTX pharmacokinetics or MTX-related adverse effects in osteosarcoma patients. It is suggested that the potential risk of delayed MTX elimination is worthy of clinical attention, and the implementation of genotyping should be considered to ensure therapeutic safety.

Methotrexate-Induced Alteration of Renal Aquaporins 1 and 2, Oxidative Stress and Tubular Apoptosis Can Be Attenuated by Omega-3 Fatty Acids Supplementation

Methotrexate (MTX) is a potent anti-cancer drug, commonly associated with nephrotoxicity via the induction of oxidative stress and apoptosis with alteration of renal water channel proteins, namely aquaporins (AQPs). Omega-3 long-chain polyunsaturated fatty acids (LC-PUFA) have shown cytoprotective effects through their anti-oxidant and antiapoptotic activities. The present study aims for the first time to explore the role of LC-PUFA against MTX-induced nephrotoxicity. Rats were divided into the following groups: saline control, LC-PUFA control, MTX, MTX + LC-PUFA (150 mg/kg), or MTX + LC-PUFA (300 mg/kg). Then, H&E staining and immunohistochemical staining for the anti-apoptosis marker B-cell lymphoma 2 (BCL-2), the apoptosis marker BCL2-Associated X Protein (BAX), the proinflammatory marker Nuclear factor kappa B (NF-kB), AQPs 1 and 2 were performed in kidney sections with an assessment of renal oxidative stress. The MTX caused a renal histopathological alteration, upregulated renal BAX and NF-kB, downregulated Bcl-2 and AQP1, altered the distribution of AQP2, and caused oxidative stress. The LC-PUFA attenuated the pathological changes and decreased renal BAX and NF-kB, increased BCL-2 and AQP1, restored the normal distribution of AQP2, and decreased the oxidative stress. Therefore, LC-PUFA is a good adjuvant to MTX to prevent its adverse effects on kidneys through its antiapoptotic, antioxidant, and anti-inflammatory effect and its role in the restoration of the expression of AQPs 1 and 2.

Reno-protective effect of mangiferin against methotrexate-induced kidney damage in male rats: PPARγ-mediated antioxidant activity

Methotrexate (MTX) is an immunosuppressant used for the treatment of cancer and autoimmune diseases. MTX has a major adverse effect, acute kidney injury, which limits its use. Mangiferin (MF) is a natural bioactive xanthonoid used as a traditional herbal supplement to boost the immune system due to its potent anti-inflammatory and antioxidant activity. The present study evaluates the protective effect of MF against MTX-induced kidney damage. Male Wistar rats received MTX to induce nephrotoxicity or were pretreated with MF for 10 constitutive days before MTX administration. MF dose-dependently improved renal functions of MTX-treated rats and this activity was correlated with increased renal expression of PPARγ, a well-known transcriptional regulator of the immune response. Pretreating rats with PPARγ inhibitor, BADGE, reduced the reno-protective activity of MF. Furthermore, MF treatment significantly reduced MTX-induced upregulation of the pro-inflammatory (NFκB, interleukin-1ß, TNF-α, and COX-2), oxidative stress (Nrf-2, hemoxygenase-1, glutathione, and malondialdehyde), and nitrosative stress (nitric oxide and iNOS) markers in the kidney. Importantly, BADGE treatment significantly reduced the anti-inflammatory and antioxidant activity of MF. Therefore, our data suggest that the reno-protective effect of MF against MTX-induced nephrotoxicity is due to inhibition of inflammation and oxidative stress in a PPAR-γ-dependent manner.

St. Jude Total Therapy studies from I to XVII for childhood acute lymphoblastic leukemia: a brief review

The therapy design of childhood acute lymphoblastic leukemia (ALL) has evolved over the past 60 years. The St. Jude Children's Research Hospital has developed 17 treatment protocols from 1962 to 2017, aiming to have the most effective and least toxic treatment form. This review summarizes each protocol's objectives, inclusion criteria, treatment phases, pharmacological agents, irradiation therapy, response criteria, risk stratification, type of relapse, and overall survival. The enhancement and successful application of preventive therapy for ALL and following a risk-stratified approach have progressively improved the cure rate of childhood ALL, with relatively few adverse sequelae. Moreover, St. Jude's scientific theme serves as a reminder of the principal factor of research directed to a catastrophic disease such as ALL.

Pediatric Onco-Nephrology: Time to Spread the Word-Part II: Long-Term Kidney Outcomes in Survivors of Childhood Malignancy and Malignancy after Kidney Transplant

Onco-nephrology is a recent and evolving medical subspecialty devoted to the care of patients with kidney disease and unique kidney-related complications in the context of cancer and its treatments, recognizing that management of kidney disease as well as the cancer itself will improve survival and quality of life. While this area has received much attention in the adult medicine sphere, similar emphasis in the pediatric realm has not yet been realized. As in adults, kidney involvement in children with cancer extends beyond the time of initial diagnosis and treatment. Many interventions, such as chemotherapy, stem cell transplant, radiation, and nephrectomy, have long-term kidney effects, including the development of chronic kidney disease (CKD) with subsequent need for dialysis and/or kidney transplant. Thus, with the improved survival of children with malignancy comes the need for ongoing monitoring of kidney function and early mitigation of kidney-related comorbidities. In addition, children with kidney transplant are at higher risk of developing malignancies than their age-matched peers. Pediatric nephrologists thus need to be aware of issues related to cancer and its treatments as they impact their own patients. These facts emphasize the necessity of pediatric nephrologists and oncologists working closely together in managing these children and highlight the importance of bringing the onco-nephrology field to our growing list of pediatric nephrology subspecialties.

Extracorporeal Treatment for Methotrexate Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup

Methotrexate is used in the treatment of many malignancies, rheumatological diseases, and inflammatory bowel disease. Toxicity from use is associated with severe morbidity and mortality. Rescue treatments include intravenous hydration, folinic acid, and, in some centers, glucarpidase. We conducted systematic reviews of the literature following published EXtracorporeal TReatments In Poisoning (EXTRIP) methods to determine the utility of extracorporeal treatments in the management of methotrexate toxicity. The quality of the evidence and the strength of recommendations (either "strong" or "weak/conditional") were graded according to the GRADE approach. A formal voting process using a modified Delphi method assessed the level of agreement between panelists on the final recommendations. A total of 92 articles met inclusion criteria. Toxicokinetic data were available on 90 patients (89 with impaired kidney function). Methotrexate was considered to be moderately dialyzable by intermittent hemodialysis. Data were available for clinical analysis on 109 patients (high-dose methotrexate [>0.5 g/m²]: 91 patients; low-dose [≤0.5 g/m²]: 18). Overall mortality in these publications was 19.5% and 26.7% in those with high-dose and low-dose methotrexate-related toxicity, respectively. Although one observational study reported lower mortality in patients treated with glucarpidase compared with those treated with hemodialysis, there were important limitations in the study. For patients with severe methotrexate toxicity receiving standard care, the EXTRIP workgroup: (1) suggested against extracorporeal treatments when glucarpidase is not administered; (2) recommended against extracorporeal treatments when glucarpidase is administered; and (3) recommended against extracorporeal treatments instead of administering glucarpidase. The quality of evidence for these recommendations was very low. Rationales for these recommendations included: (1) extracorporeal treatments mainly remove drugs in the intravascular compartment, whereas methotrexate rapidly distributes into cells; (2) extracorporeal treatments remove folinic acid; (3) in rare cases where fast removal of methotrexate is required, glucarpidase will outperform any extracorporeal treatment; and (4) extracorporeal treatments do not appear to reduce the incidence and magnitude of methotrexate toxicity.

Incidence and management of patients with methotrexate delayed elimination in the clinical practice: A Delphi study

INTRODUCTION

High-dose methotrexate (HDMTX) is administered for the treatment of some cancers. HDMTX is usually safe but may crystallize in renal tubules causing acute kidney injury (AKI). Consequently, MTX elimination is delayed, resulting in a severe and life-threatening condition. No studies have been published about the impact of MTX toxicity in Spain. This study aims to estimate the incidence and management of MTX delayed elimination and toxicity.

METHODS

A two-round Delphi study was performed to reach consensus between 10 medical experts on haemato-oncology and paediatric oncology with experience in the management of HDMTX treated patients from leading Spanish hospitals. An online questionnaire was developed based on national and international guidelines and previous evidence regarding HDMTX-related toxicity. Consensus was established at 80% agreement. Median and interquartile ranges were calculated, and incidence data were extrapolated to the Spanish general population.

RESULTS

Out of 1.475 patients estimated to receive HDMTX treatment annually in Spain, 27.5% present MTX delayed elimination and 11.6% develop HDMTX-induced AKI (35.4% with severe systemic toxicities (>grade 3) and 18.8% develop chronic renal disease). Mortality is estimated in 4.2%. Immuno-enzymatic assay is used in most of the hospitals (90%) for MTX serum level monitoring. All experts use increased supportive care and high leucovorin as first-line treatment. Available treatments in experts' hospitals in case toxicity persists are haemodialysis (90% of hospitals), glucarpidase (60%) and hemofiltration (50%). Most prevalent non-renal systemic toxicities are haematologic and mucositis (21-40% of patients). Patients with HDMTX-induced AKI require from intensive care (5% of patients), more than 3 sessions and 4 days of dialysis, and about 8.5 days of hospitalization (non-ICU patients) and 12 days in case of patients requiring ICU.

CONCLUSIONS

These results are the first evidence regarding HDMTX-induced AKI in Spain. Incidence and mortality results are in line with previous studies. Clinical management is based on preventive measures and the treatment depend on the availability in the hospital. The need for effective, safe and rapid treatment for the reduction of MTX toxic levels and the improvement of monitoring methods were noted by experts as urgent needs. Further observational studies to validate these results would be needed.

Pharmacomicrobiology of Methotrexate in Rheumatoid Arthritis: Gut Microbiome as Predictor of Therapeutic Response

Rheumatoid arthritis (RA) is a disabling autoimmune disease with invasive arthritis as the main manifestation and synovitis as the basic pathological change, which can cause progressive destruction of articular cartilage and bone, ultimately leading to joint deformity and loss of function. Since its introduction in the 1980s and its widespread use in the treatment of RA, low-dose methotrexate (MTX) therapy has dramatically changed the course and outcome of RA treatment. The clinical use of this drug will be more rational with a better understanding of the pharmacology, anti-inflammatory mechanisms of action and adverse reaction about it. At present, the current clinical status of newly diagnosed RA is that MTX is initiated first regardless of the patients’ suitability. But up to 50% of patients could not reach adequate clinical efficacy or have severe adverse events. Prior to drug initiation, a prognostic tool for treatment response is lacking, which is thought to be the most important cause of the situation. A growing body of studies have shown that differences in microbial metagenomes (including bacterial strains, genes, enzymes, proteins and/or metabolites) in the gastrointestinal tract of RA patients may at least partially determine their bioavailability and/or subsequent response to MTX. Based on this, some researchers established a random forest model to predict whether different RA patients (with different gut microbiome) would respond to MTX. Of course, MTX, in turn, alters the gut microbiome in a dose-dependent manner. The interaction between drugs and microorganisms is called pharmacomicrobiology. Then, the concept of precision medicine has been raised. In this view, we summarize the characteristics and anti-inflammatory mechanisms of MTX and highlight the interaction between gut microbiome and MTX aiming to find the optimal treatment for patients according to individual differences and discuss the application and prospect of precision medicine.

Evaluation of kidney dysfunction in childhood cancer survivors

BACKGROUND

The major increase in the survival rate among children with cancer is due to improvement in the diagnosis and treatment. Despite this increase, childhood cancer survivors (CCS) are at high risk of developing late complications such as nephrotoxicity due to chemotherapy. So, we aimed to detect early subclinical kidney dysfunction among CCS.

METHODS

This cross-sectional study was implemented on 52 survivors of childhood cancer recruited from Pediatric Oncology Unit, Menoufia University. Laboratory evaluations for each participant, including complete blood count, serum urea, creatinine, urinary protein, urinary calcium, uric acid, and serum cystatin C and urinary Neutrophil Gelatinase Associated Lipocalin (UrNGAL) by ELISA were obtained.

RESULTS

Estimated GFR was decreased in 23.1% of cases, with elevated serum cystatin C, UrNGAL and UrNGAL/Cr. There was a significant increase of Uprotein/Cr, UCa/Cr, UACR (p = 0.02), UrNGAL and UrNGAL/Cr (P < 0.001) in patients with tubular dysfunction compared without tubular dysfunction. There was a significant difference between two groups regarding cisplatin (P = 0.03) and high-dose methotrexate chemotherapy (p = 0.04). The AUCs for detecting kidney tubular dysfunction by UrNGAL and UrNGAL/Cr were 0.807 and 0.747.

CONCLUSION

A significant tubular dysfunction among childhood cancer survivors receiving chemotherapy as cisplatin and high-dose methotrexate.

IMPACT

Detection of kidney dysfunction mainly tubular in childhood cancer survivors after finishing chemotherapy. Urinary NGAL is a good predictor for detection of tubular dysfunction in childhood cancer survivors after finishing chemotherapy.

Urine volume to hydration volume ratio is associated with pharmacokinetics of high-dose methotrexate in patients with primary central nervous system lymphoma

High-dose methotrexate (HD-MTX)-based chemotherapy is the first-line treatment for primary central nervous system lymphoma (PCNSL), but is associated with severe adverse effects, including myelosuppression and renal impairment. MTX is primarily excreted by the kidneys. Renal function calculated using serum creatinine (Scr) derived from muscle may be overestimated in elderly PCNSL patients. Therefore, we aimed to construct a population pharmacokinetic model in PCNSL patients and explore the factors associated with MTX clearance. Sixteen PCNSL patients (median age, 66 years) treated with HD-MTX were included, and serum MTX concentrations were measured at 193 points in 49 courses. A population pharmacokinetic analysis was performed using NONMEM. A Monte Carlo simulation was conducted, in which serum MTX concentrations were stratified into three groups of creatine clearance (Ccr) (50, 75, and 100 ml/min) with three groups of the urine volume to hydration volume (UV/HV) ratio (<1, 1-2, and >2). The final model was constructed as follows: MTX clearance = 4.90·(Ccr/94.5)0.456 ·(UV/HV)0.458 . In the Monte Carlo simulation, serum MTX concentrations were below the standard values (10, 1, and 0.1 µM at 24, 48, and 72 h, respectively, after the start of the MTX administration) in most patients with UV/HV >2, even with Ccr of 50 ml/min. Conversely, half of the patients with UV/HV <1 and Ccr of 50 ml/min failed to achieve the standard values. The present results demonstrated that the UV/HV ratio was useful for describing the pharmacokinetics of MTX in PCNSL patients.

Medication Therapy of High-Dose Methotrexate: An Evidence-Based Practice Guideline of the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society

OBJECTIVES

A lot of medication risks related to high-dose methotrexate (HDMTX) therapy still remain to be identified and standardized. This study aims to establish an evidence-based practice guideline for individualized medication of HDMTX.

METHODS

The practice guideline was launched by the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society. The guideline was developed following the WHO handbook for guideline development and the methodology of evidence-based medicine (EBM). The guideline was initially registered in the International Practice Guidelines Registry Platform (IPGRP-2017CN021). Systematic reviews were conducted to synthesis available evidence. A multicenter cross-sectional study was conducted by questionnaires to evaluate patients' perception and willingness on individualized medication of HDMTX. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to rate the quality of evidence and to grade the strength of recommendations.

RESULTS

Multidisciplinary working groups were included in this guideline, including clinicians, pharmacists, methodologists, pharmacologists and pharmacoeconomic specialists. A total of 124 patients were involved to integrate patient values and preferences. Finally, the guideline presents 28 recommendations, regarding evaluation prior to administration (renal function, liver function, pleural effusion, comedications, genetic testing), pre-treatment and routine dosing regimen, therapeutic drug monitoring (necessity, method, timing, target concentration), leucovorin rescue (initial timing, dosage regimen and optimization), management of toxicities. Of them, 12 are strong recommendations.

CONCLUSIONS

We developed an evidence-based practice guideline with respect to HDMTX medication using a rigorous and multidisciplinary approach. This guideline provides comprehensive and practical recommendations involving the whole process of HDMTX administration to health care providers.

Effective elimination of high-dose methotrexate by repeated hemodiafiltration and high-flux hemodialysis in patients with acute kidney injury

INTRODUCTION

Acute kidney injury (AKI) after high dose methotrexate (HD-MTX) is associated with delayed MTX-excretion and life-threatening toxicity. Glucapridase, the recommended therapy, is expensive and not always available.

CASE SERIES

We describe 3 cases (69, 67, 73 years) with diffuse large B-cell lymphoma who developed AKI and early-onset severely delayed MTX elimination after HD-MTX. MTX serum concentrations were 101 and 69 μmol/L at 24 h after administration in two patients and 34 μmol/L at 32 h in the third.

MANAGEMENT AND OUTCOME

Since glucarpidase was unavailable, we performed daily high-flux hemodialysis (HF-HD) or online hemodiafiltration (HDF) sessions (median duration, 6 h). The median serum MTX elimination half-life during HDF/HF-HD sessions was similar in all patients (median, 4.4 h; IQR, 3.8-5.3 h), but serum MTX concentrations rebounded after each dialysis by a median of 40% of the trough concentrations. The three patients underwent multiple dialysis sessions, until MTX serum concentrations remained sufficiently low to be neutralized by leucovorin. Only 1 patient developed severe pancytopenia, and renal function normalized in all patients after 3-6 weeks.

DISCUSSION

In conclusion, when glucarpidase is unavailable or delayed, early, repeated and prolonged HDF/HF-HD effectively enhance MTX elimination and prevent toxicity in patients with AKI and severely delayed MTX elimination after HD-MTX.

Eicosapentaenoic and docosahexaenoic acids attenuate methotrexate-induced apoptosis and suppression of splenic T, B-Lymphocytes and macrophages with modulation of expression of CD3, CD20 and CD68

Methotrexate (MTX) is a chemotherapeutic agent used for cancer and autoimmune disorders. MTX may cause multi-organ affections. However, few studies examined MTX-induced splenic suppression and therapeutic modalities against it. This is the first study to explore the efficacy of omega-3 fatty acids; Eicosapentaenoic (EPA) and Docosahexaenoic (DHA) against MTX-induced splenic suppression and its effect on splenic macrophages and lymphocytes. Five groups of Sprague Dawley rats were used. Group 1 received saline; group 2: omega-3 only; group 3: a single dose of MTX (20 mg/kg); groups 4 and 5: MTX (20 mg/kg) + either omega-3 (150) or (300 mg/kg) once daily, respectively, given for two days before MTX and three days after it. Splenic tissues were then removed, evaluated for oxidative stress markers; GSH, MDA, and for mRNA expression of the apoptotic marker caspase-3, the anti-apoptotic marker Bcl-2 and the inflammatory cytokine TNFα. Moreover, H&E stain, Prussian blue stain for iron, and immunohistochemical staining for TNFα, T lymphocyte marker; CD3, B lymphocyte marker; CD20, and macrophage marker; CD68, were performed with morphometric analysis. EPA and DHA could decrease the MTX-induced increase in the histopathological injury score, splenic hemosiderin, splenic MDA, mRNA expression of TNFα, caspase-3 and could increase the MTX-induced decrease in Splenic GSH and mRNA expression for Bcl-2. It also decreased the MTX-induced elevation in the immunopositive area of TNFα, and increased the area percentage of CD3+, CD20+ and CD68+ cells. Therefore, omega-3 can be a promising adjuvant to help MTX action with prevention of its deleterious effects on spleen.

Outcomes of kidney injury including dialysis and kidney transplantation in pediatric oncology and hematopoietic cell transplant patients

Pediatric oncology and hematopoietic cell transplant (HCT) patients are susceptible to both acute kidney injury (AKI) and chronic kidney disease (CKD). The etiologies of AKI vary but include tumor infiltration, radiation, drug-induced toxicity, and fluid and electrolyte abnormalities including tumor lysis syndrome. HCT patients can also have additional complications such as sinusoidal obstructive syndrome, graft-versus-host disease, or thrombotic microangiopathy. For patients with severe AKI requiring dialysis, multiple modalities can be used successfully, although continuous kidney replacement therapy (CKRT) is often the principal modality for critically ill patients. While increasing numbers of pediatric cancer and HCT patients are now surviving long term, they remain at risk for a number of chronic medical conditions, including CKD. Certain high-risk patients, due to underlying risk factors or treatment-related complications, eventually develop kidney failure and may require kidney replacement therapies. Management of co-morbidities and complications associated with kidney failure, including use of erythropoietin for anemia and potential need for ongoing cancer-related treatment while on dialysis, is an additional consideration in this patient population. Kidney transplantation can be successfully performed in pediatric cancer survivors, although additional features such as specific cancer diagnosis and duration of remission should be considered.

The Role of Oxidative Stress and Inflammation in Cardiometabolic Health of Children During Cancer Treatment and Potential Impact of Key Nutrients

Significance: The 5-year survival rate of childhood cancers is now reaching 84%. However, treatments cause numerous acute and long-term side effects. These include cardiometabolic complications, namely hypertension, dyslipidemia, hyperglycemia, insulin resistance, and increased fat mass. Recent Advances: Many antineoplastic treatments can induce oxidative stress (OxS) and trigger an inflammatory response, which may cause acute and chronic side effects. Critical Issues: Clinical studies have reported a state of heightened OxS and inflammation during cancer treatment in children as the result of treatment cytotoxic action on both cancerous and noncancerous cells. Higher levels of OxS and inflammation are associated with treatment side effects and with the development of cardiometabolic complications. Key nutrients (omega-3 polyunsaturated fatty acids, dietary antioxidants, probiotics, and prebiotics) have the potential to modulate inflammatory and oxidative responses and, therefore, could be considered in the search for adverse complication prevention means as long as antineoplastic treatment efficiency is maintained. Future Directions: There is a need to better understand the relationship between cardiometabolic complications, OxS, inflammation and diet during pediatric cancer treatment, which represents the ultimate goal of this review. Antioxid. Redox Signal. 35, 293-318.

Diabetes is a risk factor for high-dose methotrexate-associated AKI in lymphoma patients

Purpose

The aim of the study was to investigate the incidence of acute kidney injury (AKI) occurring after high-dose methotrexate (HDMTX) administration and the role of type 2 diabetes (T2D) playing in the occurrence of AKI.

Methods

We assessed associations between T2D along with other confounding factors mainly including baseline estimated glomerular filtration rate (eGFR), methotrexate (MTX) elimination and urine pH, and AKI occurrence. Patients who were diagnosed as primary central nervous system lymphoma with treatment of HDMTX and with eGFR ≥60 mL/min/1.73 m² were enrolled in this study.

Results

Of the 507 courses enrolled in this study, 132 courses have T2D. Lower baseline eGFR, delayed MTX elimination, lower urine pH, and higher incidence of AKI were observed in T2D group. Using univariate logistic regression, several confounding factors including baseline eGFR, hypertension, MTX elimination, and urine alkalinization statistically and clinically important were screened out. After adjusting for these factors, T2D remained an independent association with AKI occurrence. AKI outcome had no significant relationship with severe hematological toxicity or hepatotoxicity. AKI was associated with faster eGFR decline after a series of HDMTX treatment courses.

Conclusions

Patients with T2D have a higher sensitivity to AKI when administrated with HDMTX. This conclusion addresses safety concerns for making chemotherapy regimen for this population.

Population Pharmacokinetics of High-Dose Methotrexate in Chinese Pediatric Patients With Acute Lymphoblastic Leukemia

High-dose methotrexate (HD-MTX) is widely used in pediatric acute lymphoblastic leukemia (ALL) treatment regimens. In this study, we aimed to develop a population pharmacokinetic (PK) model of HD-MTX in Chinese pediatric patients with ALL for designing personalized dosage regimens. In total, 4,517 MTX serum concentration data for 311 pediatric patients with ALL, aged 0.75–15.2 years and under HD-MTX treatment, were retrospectively collected at a tertiary Children’s Hospital in China. The non-linear mixed-effect model was used to establish the population PK model, using NONMEM software. The potential covariate effects of age, body weight, and biochemical measurements (renal and liver function) on MTX PK disposition were investigated. The model was then evaluated using goodness-of-fit, visual predictive check. MTX PK disposition was described using a three-compartment model reasonable well. Body weight, implemented as a fixed allometric function on all clearance and volume of distribution parameters, showed a substantial improvement in model fit. The final population model demonstrated that the MTX clearance estimate in a typical child with body weight of 19 kg was 6.9 L/h and the central distribution of volume estimate was 20.7 L. The serum creatinine significantly affected the MTX clearance, with a 0.97% decrease in clearance per 1 μmol/L of serum creatinine. Other covariates (e.g., age, sex, bilirubin, albumin, aspartate transaminase, concomitant medication) did not significantly affect PK properties of MTX. The proposed population PK model could describe the MTX concentration data in Chinese pediatric patients with ALL. This population PK model combined with a maximum a posteriori Bayesian approach could be used to estimate individual PK parameters, and optimize personalized MTX therapy in target patients, thus aiming to reduce toxicity and improve treatment outcomes.

Protective effects of guarana (Paullinia cupana) against methotrexate-induced intestinal damage in mice

This study aimed to examine the effects of guarana (Paullinia cupana) on intestinal damage induced by MTX in mice. Mice were classified into four groups: control, MTX, guarana (Paullinia cupana), and guarana (Paullinia cupana) together with MTX. Total antioxidant capacity together with glutathione, superoxide dismutase, MDA, ALT, AST, myeloperoxidase, total protein and IL-1β were detected in the serum. Bax and Bcl2 expressions were detected in intestine together with histopathological examination and immunohistochemical examination of caspase-9. Intoxication with MTX inhibited antioxidant and promoted myeloperoxidase activity in experimental mouse models but pre-administration of guarana ameliorated this effect by inhibiting IL-1β. Real-time quantitative PCR (qRT-PCR) analysis found that MTX intoxication upregulated BAX expression, causing apoptosis, and downregulated Bcl2 expression. These were also brought under control following guarana pre-administration. Histological examination of intestine indicated hyperplasia and desquamation of superficial epithelium of villi in the MTX-administered group, as well as round cell infiltration in the lamina propria. Pre-administration of guarana protected against these effects. The MTX group showed that caspase-9 expression was upregulated, increasing immune-reactivity in comparison to the guarana experimental groups. These combined effects lead to the conclusion that guarana has a preventative or protective effect against MTX-induced oxidative stress in the intestinal tissue.

Combination Therapy of Cisplatin and other Agents for Osteosarcoma: A Review

Background:

Osteosarcoma is the most common type of primary bone tumor in children and adolescents, which is associated with rapid progression and poor prognosis. Multimodal therapy is the most common approach utilized for osteosarcoma management, such as the application of chemotherapy in combination with surgery or radiation therapy. Cisplatin is one of the predominantly used chemotherapeutic agents for osteosarcoma. Optimally, it is employed in combination with other chemotherapeutic drugs along with surgery or radiation therapy. Despite the availability of numerous treatment approaches, the patient survival rate has not definitively improved over the past three decades.

Methods:

We have summarized all findings regarding the combination of cisplatin with other chemotherapeutic agents as well as with phytochemical compounds.

Results:

A combination of cisplatin with a phytochemical compound synergistically enhances the killing effect of cisplatin on osteosarcoma cells with fewer side effects compared to combination with other chemotherapeutic agents.

Conclusion:

Conclusively, a combination of cisplatin with selected chemotherapeutic drugs has been shown to be effective. However, the unchanged survival rate has posed an urge to search for a new combination regimen. As a collaborative effort to substantiate the therapeutic efficacy, the combination with phytochemical compounds shows a promising response both in vitro as well as in the preclinical study.

A cross-sectional study of chemotherapy-related AKI

PURPOSE

This study aims to detail the characteristics of chemotherapy-related acute kidney injury (CR-AKI) and investigate its effect on patient outcomes.

METHODS

This is a multicenter cross-sectional study of cancer patients with CR-AKI screened from hospital-acquired adult AKI patients based on a nationwide AKI survey in China.

RESULTS

Of the 3468 patients with hospital-acquired AKI, 258 cases of CR-AKI were identified. Of the patients, 20.1% (52/258) were ≥ 70 years old. Among the 258 CR-AKI cases, 61 (23.6%) reached AKI stage 3, and 75 (29.1%) reached AKI stage 2. The remaining 122 (47.3%) remained at AKI stage 1. A total of 413 chemotherapeutic agents were related to AKI, of which platinum compounds (24.5%, 101/413) were the most common. In-hospital mortality was 14.7% (38/258), and the rate of AKI non-recovery was 48.3% (100/207). AKI stage 3 (OR 2.930, 95% CI 1.156-7.427) and age ≥ 70 years (OR 3.138, 95% CI 1.309-7.519) were independent risk factors for in-hospital death. Compared to stage 2 or 3 AKI cases, a higher proportion of patients with stage 1 AKI did not recover their renal function (57.1% vs. 41.4% vs. 36.4%, P = 0.032). More AKI episodes were not recognized in patients with stage 1 AKI compared with the other two groups (82.8% vs. 60.0% vs. 36.1%, P < 0.001).

CONCLUSIONS

CR-AKI accounted for a noteworthy proportion of hospital-acquired AKI, and severe CR-AKI increased in-hospital mortality. Mild CR-AKI was more likely to be overlooked, and sustained kidney injury was common in this situation. Recognizing CR-AKI at an early stage and personalizing treatment should be emphasized in those undergoing chemotherapy.

A pharmacologically-based approach to high dose methotrexate administration to investigate nephrotoxicity and acute kidney injury biomarkers in children and adolescents with newly diagnosed osteosarcoma

PURPOSE

High dose methotrexate (HDMTX) acute kidney injury (AKI) results in prolonged hospitalization and treatment delays. Using a pharmacologically-based approach, HDMTX was administered with standard combination therapy to patients with osteosarcoma; nephrotoxicity was assessed.

METHODS

Patients were randomized by cycle to 4 h or 12 h HDMTX (12 g/m²) infusions administered with hydration, alkalization and leucovorin rescue. Urinalysis, AKI biomarkers, and estimated glomerular filtration rate using serum creatinine or cystatin C (GFR_Cr or GFR_cysC) were obtained. Serum and urine methotrexate concentrations [MTX] were measured.

RESULTS

Patients (n = 12), median (range) age 12.4 (5.7-19.2) years were enrolled; 73 MTX infusions were analyzed. Median (95% Confidence Interval) serum and urine [MTX] were 1309 (1190, 1400) µM and 16.4 (14.7, 19.4) mM at the end of 4 h infusion and 557 (493, 586) µM and 11.1 (9.9, 21.1) mM at the end of 12 h infusion. Time to serum [MTX] < 0.1 µM was 83 (80.7, 90.7) h and 87 (82.8, 92.4) h for 4 and 12 h infusions. GFR_Cr was highly variable, increased after cisplatin, and exceeded 150 ml/min/1.73 m². GFR_cysC was less variable and decreased at the end of therapy. AKI biomarkers were elevated indicating acute tubular dysfunction, however, did not differ between 4 and 12 h infusions. Radiographic and histological response were similar for patients receiving 4 h or 12 h infusions; the median percent tumor necrosis was > 95%.

CONCLUSIONS

Reducing peak serum and urine MTX concentration by prolonging the infusion duration did not alter risk of acute kidney injury. GFR_cysC was decreased at the end of therapy. Proteinuria and elevations in AKI biomarkers indicate that direct tubular damage contributes to HDMTX nephrotoxicity.

CLINICAL TRIAL

NCT01848457.