Renal insufficiency in patients treated with high dose methotrexate

Population Pharmacokinetic Study and Individual Dose Adjustments of High-Dose Methotrexate in Chinese Pediatric Patients With Acute Lymphoblastic Leukemia or Osteosarcoma

High-dose methotrexate (>0.5 g/m² ) is among the first-line chemotherapeutic agents used in treating acute lymphoblastic leukemia (ALL) and osteosarcoma in children. Despite rapid hydration, leucovorin rescue, and routine therapeutic drug monitoring, severe toxicity is not uncommon. This study aimed at developing population pharmacokinetic (popPK) models of high-dose methotrexate for ALL and osteosarcoma and demonstrating the possibility and convenience of popPK model-based individual dose optimization using R and shiny, which is more accessible, efficient, and clinician-friendly than NONMEM. The final data set consists of 36 ALL (354 observations) and 16 osteosarcoma (585 observations) patients. Covariate model building and parameter estimations were done using NONMEM and Perl-speaks-NONMEM. Diagnostic Plots and bootstrapping validated the models' performance and stability. The dose optimizer developed based on the validated models can obtain identical individual parameter estimates as NONMEM. Compared to calling a NONMEM execution and reading its output, estimating individual parameters within R reduces the execution time from 8.7-12.8 seconds to 0.4-1.0 second. For each subject, the dose optimizer can recommend (1) an individualized optimal dose and (2) an individualized range of doses. For osteosarcoma, recommended optimal doses by the optimizer resemble the final doses at which the subjects were eventually stabilized. The dose optimizers developed demonstrated the potential to inform dose adjustments using a model-based, convenient, and efficient tool for high-dose methotrexate. Although the dose optimizer is not meant to replace clinical judgment, it provides the clinician with the individual pharmacokinetics perspective by recommending the (range of) optimal dose.

A critical review of adverse effects to the kidney: mechanisms, data sources, and in silico tools to assist prediction

INTRODUCTION

The kidney is a major target for toxicity elicited by pharmaceuticals and environmental pollutants. Standard testing which often does not investigate underlying mechanisms has proven not to be an adequate hazard assessment approach. As such, there is an opportunity for the application of computational approaches that utilize multiscale data based on the Adverse Outcome Pathway (AOP) paradigm, coupled with an understanding of the chemistry underpinning the molecular initiating event (MIE) to provide a deep understanding of how structural fragments of molecules relate to specific mechanisms of nephrotoxicity. Aims covered: The aim of this investigation was to review the current scientific landscape related to computational methods, including mechanistic data, AOPs, publicly available knowledge bases and current in silico models, for the assessment of pharmaceuticals and other chemicals with regard to their potential to elicit nephrotoxicity. A list of over 250 nephrotoxicants enriched with, where possible, mechanistic and AOP-derived understanding was compiled. Expert opinion: Whilst little mechanistic evidence has been translated into AOPs, this review identified a number of data sources of in vitro, in vivo, and human data that may assist in the development of in silico models which in turn may shed light on the interrelationships between nephrotoxicity mechanisms.

Reduced methotrexate clearance and renal impairment in a boy with osteosarcoma and earlier undetected autosomal dominant polycystic kidney disease (ADPKD)

We report a 12-year-old boy with osteoblastic osteosarcoma of the right femur. He was started on chemotherapy according to the EURAMOS/COSS 1 protocol. Chemotherapy with doxorubicin/cisplatin resulted in reversible acute renal failure and methotrexate levels were repeatedly elevated. Family history suggested an autosomal dominant polycystic kidney disease. Genetic testing revealed a novel mutation c.10707_10712del (p.Val3569_3570del) in exon 36 of the PKD1 gene. Patients with autosomal dominant polycystic kidney disease may be at risk for acute renal failure during chemotherapy without signs of renal impairment. A careful family history is important to exclude risk factors for renal impairment before introducing high-dose chemotherapy.

Methotrexate induces cell swelling and necrosis in renal tubular cells

BACKGROUND

The present study was carried out to investigate if methotrexate (MTX) has a direct lethal effect in renal tubular cells, and if so, to further clarify the mechanisms of cell death.

MATERIALS AND METHODS

Renal tubular cells (LLC-PK(1) cells) were incubated with MTX (0.01 microM, 0.1 microM, and 1 microM), either alone or in combination with 0.1 microM amiloride (Na(+)/H(+) antiporter inhibitor) or 1 microM carbachol (M-cholinergic agonist). Cell viability was then determined by means of trypan blue (TB) exclusion tests and MTT assays.

RESULTS

After 4 hr incubation with 0.1 microM MTX the number of viable cells was decreased by 18% in comparison with control cells, and the proportion of dead cells was increased by 38%. Cell death induced by MTX was time-dependent and did not show apoptotic features. On the contrary, cell swelling was discovered. This cell death was prevented by co-incubating the cells with amiloride or carbachol.

CONCLUSIONS

MTX induces cell swelling and cell death in renal tubular LLC-PK(1) cells. The tubular cell death induced by MTX is time-dependent. Cell death can be prevented by co-incubating with amiloride, thus indicating that the Na(+)/H(+) antiporter and possibly other volume regulatory factors in renal tubular cells are involved in MTX-induced renal failure.

Methotrexate causes oxidative stress in rat kidney tissues

AIM

Methotrexate (MTX), a folic acid antagonist, is one of the chemotherapeutic agents widely used in the treatment of some types of cancers. Nephrotoxicity is one of the complications of MTX treatment. The aim of this study was to investigate possible effects of MTX treatment on the oxidant/antioxidant status in rat kidney tissues and enzymatic mechanisms leading to nephrotoxicity.

METHODS

For this aim, 10 Sprague-Dawley type female rats of 4 weeks old were used in the study. The animals were divided into two groups randomly. Five of them were used as control, and the others were treated with MTX intravenously (60 mg/m2 of body surface area per week) for 7 weeks. At the end of this period, they were sacrificed, and kidney tissues were removed to be used in the analyses of malondialdehyde (MDA) levels, antioxidant potential (AOP) values, and superoxide dismutase, catalase, glutathione peroxidase, xanthine oxidase, adenosine deaminase, and 5' nucleotidase enzyme activities.

RESULTS

There was significant increase in the MDA level in the MTX group compared with the control group (1.74+/-0.23 nmol/mg vs. 1.04+/-0.30 nmol/mg; p<0.05, respectively). There were however no meaningful differences between enzyme activities and AOP values of the groups.

CONCLUSION

It has been suggested that MTX leads to oxidative stress in rat kidney tissues, which might be one of the reasons for MTX-induced nephrotoxicity.

High-dose methotrexate-associated acute renal failure may be an avoidable complication

A 17-year-old boy with acute lymphoblastic leukemia developed acute renal failure within 48 h of an intravenous high-dose methotrexate (5 g/m2) infusion. His renal function returned to baseline 14 days later with supportive care, folinic acid rescue, and urinary alkalinization. A retrospective review revealed that the patient had been exposed to iopamidol, an intravenous contrast medium, on the day prior to the commencement of methotrexate treatment. Methotrexate-associated nephropathy is a rare complication in pediatric oncology, and a review of the literature suggests that exposure to nephrotoxic agents may be a significant but perhaps underrecognized risk factor for its development.

Use of plasma exchange in methotrexate removal in a patient with osteosarcoma and acute renal insufficiency

Acute renal failure induced by methotrexate (MTX) can be lethal because renal excretion of the drug can be delayed. Pre-existing renal impairment, abstention, or underdosage of folinic acid and inadequate hydration facilitate toxicity. The prolonged high serum levels of MTX result in severe mucositis and pancytopenia, but strategies useful to accelerate MTX removal have not been universally accepted. We report a case of a 13-year-old girl with osteosarcoma who was treated with high-dose MTX because of thoracic tumor recurrence. No side effects were observed after 2 cycles of high-dose MTX; however, after the third cycle there was a delayed MTX elimination followed by clinical toxicity. Forty hours post-MTX infusion the serum level of MTX was 5.39 x 10(-4) mol/L. Treatment was based on symptomatic measures, such as maintenance of an abundant and alkaline diuresis and parenteral administration of folinic acid. Concomitantly, plasma exchange was employed to accelerate MTX removal and reduce its toxicity. After 24 days, she was discharged from the hospital, and her renal function recovered gradually.

Toxicity of chemotherapy

Because anticancer drugs are cytotoxic for normal as well as neoplastic cells, the range of unwanted effects that accompanies their use is broad. Many of the side effects are potentially life-threatening or seriously debilitating. Many are similar to, and readily confused with, direct or indirect (paraneoplastic) consequences of the cancer itself. Recognition of drug side effects is vital for optimal patient care, because early withdrawal of the offending agent and institution of appropriate treatment have the potential to significantly reduce the overall morbidity and mortality associated with the diagnosis of cancer.

Renal effects of aspirin and low dose methotrexate in rheumatoid arthritis

OBJECTIVES

The aim of this investigation was to study the glomerular and tubular effects of low doses (15 mg) of methotrexate in patients with rheumatoid arthritis with and without combined treatment with aspirin (2 g single dose).

METHODS

Renal function was measured by the plasma clearance of EDTA labelled with chromium-51 (51Cr-EDTA) and mercaptoacetyltriglycine labelled with technetium-99m (99mTc-MAG-3).

RESULTS

Clearance of 51Cr-EDTA was reduced from 98 (6) to 87 (5) ml/min (mean (SEM)) for patients receiving methotrexate only and further reduced to 76 (5) ml/min for patients receiving methotrexate and aspirin. This effect was reversible as 51Cr-EDTA increased to 85 (6) ml/min during continued treatment with methotrexate alone. Clearance of 99mTc-MAG-3 also decreased from 366 (18) to 315 (17) ml/min in patients receiving methotrexate alone and further to 295 (17) ml/min during treatment with aspirin and methotrexate. Continued treatment with methotrexate alone resulted in a further decrease in the 99mTc-MAG-3 clearance to 253 (17) ml/min.

CONCLUSIONS

The study shows that treatment with low doses of methotrexate particularly when combined with aspirin affects glomerular and tubular function. These effects may be of clinical importance and renal function should therefore be monitored with more sensitive methods than serum creatinine as this may not reflect these changes.