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

Cancer drugs and acute kidney injury: new therapies and new challenges

PURPOSE OF REVIEW

Cancer therapies continue to evolve at a rapid pace and although novel treatments, including immunotherapies and targeted therapies have allowed for substantial improvements in cancer survival, they carry associated risks of acute kidney injury (AKI). We aim to summarize the existing literature on AKI associated with the spectrum of systemic cancer treatments, including conventional chemotherapies, newer immunotherapies, and the growing number of targeted cancer therapies, which may be associated with both AKI and 'pseudo-AKI'.

RECENT FINDINGS

Conventional cytotoxic chemotherapies (e.g. cisplatin and other platinum-based agents, methotrexate, pemetrexed, ifosfamide, etc.) with well recognized nephrotoxicities (predominantly tubulointerstitial injury) remain in widespread use. Immunotherapies (e.g., immune checkpoint inhibitors and CAR-T therapies) may be associated with kidney immune-related adverse events, most often acute interstitial nephritis, and rarely, glomerular disease. Recently, multiple targeted cancer therapies have been associated with reduced renal tubular secretion of creatinine, causing elevations in serum creatinine and apparent 'pseudo-AKI'. To complicate matters further, these agents have had biopsy-proven, 'true' kidney injury attributed to them in numerous case reports.

SUMMARY

Clinicians in nephrology and oncology must be aware of the various potential kidney risks with these agents and recognize those with clinically meaningful impact on both cancer and kidney outcomes.

An observational study of root-cause analysis of medication errors in elderly with methotrexate toxicity

INTRODUCTION

Medication errors are inherent in a healthcare system. This results in both time and cost burdens for both the patient and the health system. The aim of this study was to conduct a root-cause analysis of medication errors in elderly patients with methotrexate toxicity, analyze associated factors, and propose solutions.

METHODS

This single-center prospective study was designed to identify medication errors in cases of methotrexate toxicity between November 2022 to May 2023. Categorical data and free-text data are used to describe incidents. Harm assessment, factors related to medication errors, and preventability were evaluated for each case. Possible strategies to prevent similar occurrences are discussed.

RESULTS

Out of a total of 15 patients who presented during the study period, nine suffered from methotrexate toxicity due to medication errors. Most medication errors occurred during prescribing or dispensing (seven cases). Inadequate knowledge about medication and dosage, inadequate communication was identified as a contributing factor for all medication errors. Patients on long-term methotrexate treatment are at high risk of methotrexate toxicity.

CONCLUSION

This study highlights the challenges of health literacy and lacking communication between healthcare providers and patients that can be met through community pharmacy programs for the elderly in lower-middle-income countries.

Metabolic management of accidental intoxication

PURPOSE OF REVIEW

Unintentional intoxication comprises a major chunk of all intoxications. Most patients are in the pediatric age group with another set of patients being the elderly. Substances found to cause accidental intoxication vary from country to country and even within different regions of a country. Frequent reviews of current literature are needed to be abreast of trends.

RECENT FINDINGS

Prescription drugs and household chemicals are major culprits when it comes to accidental intoxication. Acetaminophen, digoxin and metformin are some of the prominent prescription drugs frequently associated with unintentional intoxications. Increasingly alcohol based hand sanitizers are becoming an important etiology of these events, following their increased usage during the COVID-19 pandemic. Pattern recognition to identify class of intoxicant and supportive care including prevention of further absorption and increased excretion are cornerstones of therapy. Antidote when available should be used promptly.

SUMMARY

Knowledge about current epidemiology of accidental intoxications, toxidrome pattern recognition and appropriate antidote usage beside adequate and timely supportive care help in successful management of the unfortunate victim of accidental intoxication.

Precision nephrotoxicity testing using 3D in vitro models

Nephrotoxicity is a significant concern during the development of new drugs or when assessing the safety of chemicals in consumer products. Traditional methods for testing nephrotoxicity involve animal models or 2D in vitro cell cultures, the latter of which lack the complexity and functionality of the human kidney. 3D in vitro models are created by culturing human primary kidney cells derived from urine in a 3D microenvironment that mimics the fluid shear stresses of the kidney. Thus, 3D in vitro models provide more accurate and reliable predictions of human nephrotoxicity compared to existing 2D models. In this review, we focus on precision nephrotoxicity testing using 3D in vitro models with human autologous urine-derived kidney cells as a promising approach for evaluating drug safety.

Management of Poisonings and Intoxications

Poisoning occurs after exposure to any of a number of substances, including medicines, which can result in severe toxicity including death. The nephrologist may be involved in poisonings that cause kidney disease and for targeted treatments. The overall approach to the poisoned patient involves the initial acute resuscitation and performing a risk assessment, whereby the exposure is considered in terms of the anticipated severity and in the context of the patient's status and treatments that may be required. Time-critical interventions such as gastrointestinal decontamination ( e.g. , activated charcoal) and antidotes are administered when indicated. The nephrologist is usually involved when elimination enhancement techniques are required, such as urine alkalinization or extracorporeal treatments. There is increasing data to guide decision making for the use of extracorporeal treatments in the poisoned patient. Principles to consider are clinical indications such as whether severe toxicity is present, anticipated, and/or will persist and whether the poison will be significantly removed by the extracorporeal treatment. Extracorporeal clearance is maximized for low-molecular weight drugs that are water soluble with minimal protein binding (<80%) and low endogenous clearance and volume of distribution. The dosage of some antidotes ( e.g. , N-acetylcysteine, ethanol, fomepizole) should be increased to maintain therapeutic concentrations once the extracorporeal treatment is initiated. To maximize the effect of an extracorporeal treatment, blood and effluent flows should be optimized, the filter with the largest surface area selected, and duration tailored to remove enough poison to reduce toxicity. Intermittent hemodialysis is recommended in most cases when an extracorporeal treatment is required because it is the most efficient, and continuous kidney replacement therapy is prescribed in some circumstances, particularly if intermittent hemodialysis is not readily available.

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.

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.

[Hemoperfusion and plasmapheresis in the intensive care unit]

In addition to kidney replacement procedures, several other extracorporeal procedures are employed in the intensive care unit. Hemoperfusion with activated charcoal was the predominant treatment used for removal of toxins from the 1970s until the millennium. Nowadays, this treatment does no longer play a clinically meaningful role as even strongly protein-bound toxins can be removed by effective dialysis procedures in case poisoning. The concept of a cytokine adsorber was introduced 10 years ago, which is directed towards withstanding the cytokine storm. Despite negative data from prospective randomized controlled studies, its use is steadily increasing in Germany. A totally different treatment concept is the biomimetic pathogen adsorber, which removes bacteria, viruses and fungi from the bloodstream by binding to immobilized heparin. Whether this rapid reduction of the pathogen load translates into an improvement of clinically relevant endpoints is unclear, as prospective randomized controlled studies are lacking. For the early hours of septic shock a very old procedure, plasmapheresis, has recently regained interest. The results of two large randomized controlled studies in this setting from Europe and Canada will become available in 2025/2026. The rationale to use plasma exchange in early sepsis is that this procedure not only removes cytokines but also replenishes reduced levels of protective factors, such as angiopoietin‑1, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13) and protein C, if fresh plasma is used as exchange fluid. All afore mentioned procedures do not only have a different mode of action but are also used at seperate time points of bloodstream infections and/or sepsis.

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.

Hämoperfusion und Plasmapherese auf der Intensivstation

Neben Nierenersatzverfahren werden auf der Intensivstation mehrere andere extrakorporale Verfahren eingesetzt. In den 1970er- bis 2000er-Jahren stand die Hämoperfusion mit Aktivkohlekapseln zur Entfernung von Toxinen im Vordergrund. Dies ist mittlerweile aufgrund der effektiven Dialyseverfahren, die im Vergiftungsfall auch stark proteingebundene Toxine entfernen, fast bedeutungslos geworden. Vor 10 Jahren erlebte ein Zytokinadsorber die Markteinführung, der darauf gerichtet ist, den „Zytokinsturm“ zu überstehen. Dieser erfreut sich trotz ernüchternder Daten aus prospektiven, randomisierten, kontrollierten Studien wachsender Beliebtheit. Ein gänzlich anderes Therapiekonzept ist der biomimetische Pathogenadsorber, der Bakterien, Viren und Pilze durch Bindung an immobilisiertes Heparin aus dem Blutstrom entfernt. Ob sich diese schnelle Reduktion der Pathogenlast in eine Verbesserung klinisch relevanter Endpunkte übersetzt, ist unklar, da hier prospektive, randomisierte und kontrollierte Studien gänzlich fehlen. Für ein sehr altes Verfahren, nämlich die Plasmapherese, werden wir für die Frühphase der Sepsis bis zum Jahr 2025/2026 Ergebnisse aus 2 großen randomisierten, kontrollierten Studien aus Europa und Kanada erhalten. Neben der Entfernung von Zytokinen erhofft man sich durch die Verwendung von Frischplasma als Austauschflüssigkeit auch das Wiederauffüllen reduzierter protektiver Faktoren wie Angiopoietin 1, ADAMTS13 („a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13“) und Protein C. Alle genannten Verfahren funktionieren nicht nur unterschiedlich, sondern werden auch zu unterschiedlichen Zeitpunkten der Blutstrominfektion/Sepsis eingesetzt.