Methotrexate-induced toxicity pharmacogenetics: an umbrella review of systematic reviews and meta-analyses

Risk factors associated with high-dose methotrexate induced toxicities

INTRODUCTION

High-dose methotrexate (HDMTX) therapy poses challenges in various neoplasms due to individualized pharmacokinetics and associated adverse effects. Our purpose is to identify early risk factors associated with HDMTX-induced toxicities, paving the way for personalized treatment.

AREAS COVERED

A systematic review of PubMed and Cochrane databases was conducted for articles from inception to July 2023. Eligible studies included reviews, clinical trials, and real-world analyses. Irrelevant studies were excluded, and manual searches and citation reviews were performed. Factors such as MTX exposure, drug interactions, demographics, serum albumin, urine pH, serum calcium, and genetic polymorphisms affecting MTX transport (e.g. SLCO1B1), intracellular folate metabolism (MTHFR), cell development (ARID5B), metabolic pathways (UGT1A1, PNPLA3), as well as epigenetics were identified.

EXPERT OPINION

This comprehensive review aids researchers and clinicians in early identification of HDMTX toxicity risk factors. By understanding the multifaceted risk factors associated with hematologic malignancies, personalized treatment approaches can be tailored to optimize therapeutic outcomes.

Safety profile of methotrexate used off-label in ectopic pregnancy: an active monitoring study based on a Chinese hospital pharmacovigilance system

OBJECTIVE

Methotrexate (MTX) is characterized as first-line therapy although its indication of ectopic pregnancy is off-label use. We aimed to conduct a retrospective cohort study to investigate the incidence, characteristics of adverse drug reactions (ADRs) of MTX, provide valuable insights for medical workers.

METHODS

Basing on China Hospital Pharmacovigilance System (CHPS), a retrospective analysis was performed to evaluate the safety of MTX (n = 672). An active monitoring model was set to detect ADR signals from the hospital information system. Frequency, Common Terminology Criteria for Adverse Events (CTCAE) grade proportion and association of dose exposure with ADRs were presented as outcomes.

RESULTS

The total incidence of ADRs was 54.0%. Anaemia (37.6%) was the most frequent ADR, followed by hepatic function abnormal (11.3%), hyperuricemia (6.1%), neutropenia (4.6%), leukopenia (4.0%), and dyslipidaemia (2.5%). For the composition of all ADRs, CTCAE grade one, two and three dominated for 86.3%, 12.1% and 1.6%, respectively. The severity of hepatic function abnormal was more serious in the two-dose exposed group (p = .021), while other types of ADRs had no statistical or clinical differences. Logistic regression analysis showed the incidence of any ADRs (OR 1.87 [1.31-2.64]; p = .001), hepatic function abnormal (OR 2.75 [1.69-4.48]; p < .001), dyslipidaemia (OR 5.15 [1.87-14.13]; p = .001) were significantly higher in the two-dose exposed group. After adjusted, the positive associations were still maintained.

CONCLUSIONS

MTX is quite safe in ectopic pregnancy, despite its mild to moderate hematotoxicity, hepatotoxicity and nephrotoxicity. Taking CHPS can present the accurate denominator of the incidence of adverse drug reactions into account, our study advocates that it may have great potential to be used as an active monitoring tool for off-label drug use risk management.

Low serum level and chronic toxicity for methotrexate. Case Report

INTRODUCTION

Methotrexate (MTX) is a folic acid antagonist used to treat different immunological or proliferative illnesses because of its anti-proliferative and anti-inflammatory effects. MTX Toxicity is considered a severe problem. Although acute toxicity related to high-dose administration (doses ≥500 mg/m2) can be predicted based on the given dose, chronic toxicity still has no specific factors to predict it, so treatment depends on the history and symptoms of toxicity. MTX was initially used for oncology indications with high cyclic doses, then expanded to non-oncology indications with different low doses and frequencies. This significant change in doses resulted in dosing errors that contributed to MTX toxicity reports. Measures to prevent the toxicity of MTX should be implemented.

CASE

A 66-year-old female patient ingested 10 mg of MTX daily for one month instead of the once-toxicity symptoms. The serum level of MTX was requested, and treatment with folinic acid was initiated until the patient improved with the discontinuation of MTX.

DISCUSSION

There is limited literature about the lack the total cumulative dose, duration of intake, or serum level of MTX. All this information was provided in this case report, but drug-drug interactions were not reviewed, although aspirin and pantoprazole were identified as having interactions with methotrexate in this patient. Minimum total cumulative dose identification may help assess the toxicity risk in such patients.

CONCLUSION

Low-dose MTX chronic toxicity still needs further information to guide the patient's risk of toxicity and when to initiate treatment. Safety-practical measures should be implemented to prevent such administration errors.

Aucubin alleviates methotrexate-induced enteritis in rats by inducing autophagy

One of the toxic side effects of methotrexate (MTX) is enteritis. Aucubin, an iridoid glycoside derived from traditional medicinal herbs, has been proven to have anti-inflammation, anti-apoptosis and anti-oxidation properties. This work explored the effect and mechanism of aucubin in treating MTX-induced enteritis in a rat model. Two doses of aucubin (5 and 10 mg/kg) were adopted for the assessment of its pharmacological activity. We observed that in rats with MTX-induced enteritis, the body weight and small intestinal weight decreased. The intestine barrier was injured, as reflected by pathological examinations and an increase in D-lactate and diamine oxidase concentration in serum. Intestinal inflammation was shown by the observation of macrophages in the intestine and the concentrations of inflammatory cytokines tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in serum. The NLR family pyrin domain containing 3 (NLRP3) inflammasome was shown to be activated by the enhancement of NLRP3, cleaved-caspase 1, IL-18 and IL-1β. Moreover, autophagy was reflected by transmission electron microscopy as slightly induced, along with changes in autophagy-related markers microtubule-associated protein 1 light chain 3 (LC3) and Beclin1. Remarkably, aucubin treatment attenuated the MTX-induced disease activity index increase, intestinal damage, inflammatory response and NLRP3 inflammasome activation, but provoked autophagy. Rapamycin, an autophagy activator, showed similar therapeutic effects to aucubin on MTX-induced enteritis. However, 3-methyladenine, an autophagy inhibitor, reversed the protective effects of aucubin. These findings prompted the hypothesis that aucubin alleviates MTX-induced enteritis by aggravating autophagy. This study might provide evidence for further investigation on the therapeutic role of aucubin in MTX-resulted enteritis.

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.

Clinical utility of overviews on adverse events of pharmacological interventions

BACKGROUND

Overviews (i.e., systematic reviews of systematic reviews, meta-reviews, umbrella reviews) are a relatively new type of evidence synthesis. Among others, one reason to conduct an overview is to investigate adverse events (AEs) associated with a healthcare intervention. Overviews aim to provide easily accessible information for healthcare decision-makers including clinicians. We aimed to evaluate the clinical utility of overviews investigating AEs.

METHODS

We used a sample of 27 overviews exclusively investigating drug-related adverse events published until 2021 identified in a prior project. We defined clinical utility as the extent to which overviews are perceived to be useful in clinical practice. Each included overview was assigned to one of seven pharmacological experts with expertise on the topic of the overview. The clinical utility and value of these overviews were determined using a self-developed assessment tool. This included four open-ended questions and a ranking of three clinical utility statements completed by clinicians. We calculated frequencies for the ranked clinical utility statements and coded the answers to the open-ended questions using an inductive approach.

RESULTS

The overall agreement with the provided statements was high. According to the assessments, 67% of the included overviews generated new knowledge. In 93% of the assessments, the overviews were found to add value to the existing literature. The overviews were rated as more useful than the individual included systematic reviews (SRs) in 85% of the assessments. The answers to the open-ended questions revealed two key aspects of clinical utility in the included overviews. Firstly, it was considered useful that they provide a summary of available evidence (e.g., along with additional assessments, or across different populations, or in different settings that have not been evaluated together in the included SRs). Secondly, it was found useful if overviews conducted a new meta-analysis to answer specific research questions that had not been answered previously.

CONCLUSIONS

Overviews on drug-related AEs are considered valuable for clinical practice by clinicians. They can make available evidence on AEs more accessible and provide a comprehensive view of available evidence. As the role of overviews evolves, investigations such as this can identify areas of value.

Can Pharmacogenetic Variants in TPMT, MTHFR and SLCO1B1 Genes Be Used as Potential Markers of Outcome Prediction in Systemic Sclerosis Patients?

Systemic sclerosis (SSc) is a rare connective tissue disorder with highest morbidity and mortality among rheumatologic diseases. Disease progression is highly heterogeneous between patients, implying a strong need for individualization of therapy. Four pharmacogenetic variants, namely TPMT rs1800460, TPMT rs1142345, MTHFR rs1801133 and SLCO1B1 rs4149056 were tested for association with severe disease outcomes in 102 patients with SSc from Serbia treated either with immunosuppressants azathioprine (AZA) and methotrexate (MTX) or with other types of medications. Genotyping was performed using PCR-RFLP and direct Sanger sequencing. R software was used for statistical analysis and development of polygenic risk score (PRS) model. Association was found between MTHFR rs1801133 and higher risk for elevated systolic pressure in all patients except those prescribed with MTX, and higher risk for kidney insufficiency in patients prescribed with other types of drugs. In patients treated with MTX, variant SLCO1B1 rs4149056 was protective against kidney insufficiency. For patients receiving MTX a trend was shown for having a higher PRS rank and elevated systolic pressure. Our results open a door wide for more extensive research on pharmacogenomics markers in patients with SSc. Altogether, pharmacogenomics markers could predict the outcome of patients with SSc and help in prevention of adverse drug reactions.

Inhibition of methotrexate induced toxicity in the adult rat spleen by adalimumab

Methotrexate (MTX) has been in use for the treatment of rheumatoid arthritis (RA), psoriasis, and cancer since 1948. Its toxic side effects on tissues and organs have been well documented but splenotoxicity has not been addressed. This study set out to investigate this issue by examining the effectiveness of anti-TNFα agents against MTX-induced toxicity in T lymphocytes and macrophages via the regulation of CD3, CD68, and CD200R. Twenty-four Sprague Dawley rats were allocated to three groups: control (received saline solution only), MTX (20 mg/kg of single-dose of MTX), and Ada + MTX (single dose of 10 mg/kg Adalimumab before MTX administration). The spleens were removed 5 days after MTX administration. The number of CD3+/mm3cells for the control, MTX and Ada + MTX groups were, respectively, 2.69 ± 0.86, 20.51 ± 2.7, (p = 0.000) and 11.07 ± 2.01 (p = 0.000). The number of CD68+ macrophages/mm3 in the control, MTX and Ada + MTX groups were, respectively, 8.62 ± 1.08, 38.19 ± 1.37 (p = 0.000), and 16.87 ± 12.57 (p = 0.000). The number of macrophages that were CD200R+/mm3 in the control, MTX, and Ada + MTX groups were 3.33 ± 1.66, 25.77 ± 2.37 (p = 0.000), and 8.68 ± 2.66 (p = 0.000), respectively. We also observed that Ada reduced the numerical densities of these cells following MTX administration (p < 0.05). Ada may, therefore, be a promising candidate for the prevention of the deleterious effects on T lymphocytes and macrophages of MTX-induced toxicity.

Methotrexate and cardiovascular prevention: an appraisal of the current evidence

New evidence continues to accumulate regarding a significant association between excessive inflammation and dysregulated immunity (local and systemic) and the risk of cardiovascular events in different patient cohorts. Whilst research has sought to identify novel atheroprotective therapies targeting inflammation and immunity, several marketed drugs for rheumatological conditions may serve a similar purpose. One such drug, methotrexate, has been used since 1948 for treating cancer and, more recently, for a wide range of dysimmune conditions. Over the last 30 years, epidemiological and experimental studies have shown that methotrexate is independently associated with a reduced risk of cardiovascular disease, particularly in rheumatological patients, and exerts several beneficial effects on vascular homeostasis and blood pressure control. This review article discusses the current challenges with managing cardiovascular risk and the new frontiers offered by drug discovery and drug repurposing targeting inflammation and immunity with a focus on methotrexate. Specifically, the article critically appraises the results of observational, cross-sectional and intervention studies investigating the effects of methotrexate on overall cardiovascular risk and individual risk factors. It also discusses the putative molecular mechanisms underpinning the atheroprotective effects of methotrexate and the practical advantages of using methotrexate in cardiovascular prevention, and highlights future research directions in this area.

Association between high-dose methotrexate-induced toxicity and polymorphisms within methotrexate pathway genes in acute lymphoblastic leukemia

Methotrexate (MTX) is a folic acid antagonist, the mechanism of action is to inhibit DNA synthesis, repair and cell proliferation by decreasing the activities of several folate-dependent enzymes. It is widely used as a chemotherapy drug for children and adults with malignant tumors. High-dose methotrexate (HD-MTX) is an effective treatment for extramedullary infiltration and systemic consolidation in children with acute lymphoblastic leukemia (ALL). However, significant toxicity results in most patients treated with HD-MTX, which limits its use. HD-MTX-induced toxicity is heterogeneous, and this heterogeneity may be related to gene polymorphisms in related enzymes of the MTX intracellular metabolic pathway. To gain a deeper understanding of the differences in toxicity induced by HD-MTX in individuals, the present review examines the correlation between HD-MTX-induced toxicity and the gene polymorphisms of related enzymes in the MTX metabolic pathway in ALL. In this review, we conclude that only the association of SLCO1B1 and ARID5B gene polymorphisms with plasma levels of MTX and MTX-related toxicity is clearly described. These results suggest that SLCO1B1 and ARID5B gene polymorphisms should be evaluated before HD-MTX treatment. In addition, considering factors such as age and race, the other exact predictor of MTX induced toxicity in ALL needs to be further determined.

A review found heterogeneous approaches and insufficient reporting in overviews on adverse events

OBJECTIVES

To investigate reporting and methodological characteristics of overviews on adverse (drug-associated) events (AEs) of pharmacological interventions.

STUDY DESIGN AND SETTING

We searched MEDLINE, Embase, Epistemonikos, and the Cochrane Database of Systematic Reviews from inception to May 17, 2021 for overviews exclusively investigating AEs of pharmacological interventions. We extracted general, reporting, and methodological characteristics and analyzed data descriptively.

RESULTS

We included 27 overviews, 70% of which were published in 2016 or later. The most common nomenclature in the title was "overview" (56%), followed by "umbrella review" (26%). The median number of included systematic reviews (SRs) in each overview was 15 (interquartile range 7-34). Study selection methods were reported in 52%, methods for data extraction in 67%, and methods for critical appraisal in 63% of overviews. An assessment of methodological quality of included SRs was performed in 70% of overviews. Only 22% of overviews reported strategies for dealing with overlapping SRs. An assessment of the certainty of the evidence was performed in 33% of overviews.

CONCLUSION

To ensure methodological rigor, authors of overviews on AEs should follow available guidance for the conduct and reporting of overviews.

Methodological approaches for assessing certainty of the evidence in umbrella reviews: A scoping review

INTRODUCTION

The number of umbrella reviews (URs) that compiled systematic reviews and meta-analysis (SR-MAs) has increased dramatically over recent years. No formal guidance for assessing the certainty of evidence in URs of meta-analyses exists nowadays. URs of non-interventional studies help establish evidence linking exposure to certain health outcomes in a population. This study aims to identify and describe the methodological approaches for assessing the certainty of the evidence in published URs of non-interventions.

METHODS

We searched from 3 databases including PubMed, Embase, and The Cochrane Library from May 2010 to September 2021. We included URs that included SR-MAs of studies with non-interventions. Two independent reviewers screened and extracted data. We compared URs characteristics stratified by publication year, journal ranking, journal impact factor using Chi-square test.

RESULTS

Ninety-nine URs have been included. Most were SR-MAs of observational studies evaluating association of non-modifiable risk factors with some outcomes. Only half (56.6%) of the included URs assessed the certainty of the evidence. The most frequently used criteria is credibility assessment (80.4%), followed by GRADE approach (14.3%). URs published in journals with higher journal impact factor assessed certainty of evidence than URs published in lower impact group (77.1 versus 37.2% respectively, p < 0.05). However, criteria for credibility assessment used in four of the seven URs that were published in top ranking journals were slightly varied.

CONCLUSIONS

Half of URs of MAs of non-interventional studies have assessed the certainty of the evidence, in which criteria for credibility assessment was the commonly used method. Guidance and standards are required to ensure the methodological rigor and consistency of certainty of evidence assessment for URs.

Unexpected severe hepatic and skin toxicities during high dose methotrexate course for osteosarcoma

INTRODUCTION

high dose methotrexate (HD-MTX) regimen is used in osteosarcoma, leukemia and lymphoma treatment. Osteosarcoma is mostly diagnosed in children and adolescents. Most frequent methotrexate toxicities are mucositis, myelosuppression, renal failure, hepatitis and necrotizing encephalopathy. Toxicities increase with renal impairment, denutrition, in older patients, with some pharmacogenetics factors or with drug interactions.

CASE REPORT

We report a 16th years old woman diagnosed with osteosarcoma and experienced an unexpected severe hepatic and skin toxicities as toxic epidermal necrolys, Steven Johnson syndrome.

MANAGEMENT AND OUTCOME

This toxicity occurred despite acid folinic rescue performed as good practice recommendation. Fourteen hours after methotrexate administration, renal failure was observed and after 72 h an erythematous rash and epidermal detachment with toxic epidermal necrolys. Seven days after methotrexate administration, hepatic failure began until grade IV cytolysis. High dose of folinic acid were administered during all severe toxicities. Methotrexate were not longer administered to this young patient and chemotherapy with ifosfamide (IFO), doxorubicine and cisplatin were performed in this patient and complete histologic response were observed in the surgical bone resection.

DISCUSSION

No classical toxicities risk factors were identified in this patient but a homozygote mutation of MTHFR gene and homozygote SLCO1B1 gene mutation were found. MTHFR and SLCO1B1 are both implicated in methotrexate metabolism.

Differences in Administration of Methotrexate and Impact on Outcome in Low-Risk Gestational Trophoblastic Neoplasia

Simple Summary

Low-risk gestational trophoblastic neoplasia is a rare but highly curable malignancy. The most common first line treatment is methotrexate, which can be administered in different forms. In order to investigate the impact of route of administration on methotrexate resistance, toxicity demanding treatment switch, complete remission and relapse, we performed an observational study including women with low-risk gestational trophoblastic neoplasia in a population-based setting in Sweden and Denmark. We found that oral compared to intra-muscular administration of methotrexate gives a higher rate of drug resistance, but does not affect rates of complete remission, recurrence or overall survival. Intra-muscular treatment was associated with more toxicity leading to switch of treatment. We conclude that, although a larger proportion of women develop drug resistance, oral methotrexate, which is easy to administer and highly tolerable, could be an option for well-informed and motivated women.

Abstract

Methotrexate (MTX) is frequently used as first-line treatment for low-risk gestational trophoblastic neoplasia (GTN). Intravenous and intramuscular (im) routes of administration are the most common methods, although oral administration is used by some Scandinavian centers. The primary aim of this study was to assess the impact of form of administration (im/oral) on resistance to methotrexate (MTX-R) treatment in low-risk GTN. Secondary aims were time to hCG normalization, rates of toxicity-induced treatment switch, and rates of complete remission and recurrence. In total, 170 women treated at Karolinska University Hospital in Sweden and Aarhus University Hospital in Denmark between 1994 and 2018 were included, of whom 107 were given im and 63 oral MTX. MTX-R developed in 35% and 54% in the im and oral groups, respectively (p = 0.01). There was no difference in days to hCG normalization (42 vs. 41 days, p = 0.50) for MTX-sensitive women. Toxicity-induced treatment switch was only seen in the im group. Complete remission was obtained in 99.1% and 100% (p = 0.44), and recurrence rate within one year was 2.8% and 1.6% (p = 0.29). The form of administration of MTX had a significant impact on development of MTX-R and treatment-associated toxicity, but does not affect rates of complete remission, recurrence or survival.

Evaluation by different mechanisms of the protective effects of vitamin B12 on methotrexate nephrotoxicity

Methotrexate is used for cure of many cancer types. It has many side effects. For this reason, obtaining a nephroprotective agent is obligatory. In the study, our aim is to determine probable effects of Vitamin B12 on MTX caused kidney damages in rats. Rats were randomly divided into 4 groups, including 8 animals in each group. Control group, VitB12 group (3 μg-kg-ip B12 throughout 15 days), MTX group (at the 8th day of experiment, a single dose of 20 mg-kg-ip MTX), Vit B12 + MTX group (3 μg-kg-ip B12 throughout 15 days and at the 8th day of experiment, a single dose of 20 mg-kg-ip MTX) Animals were anesthetized and kidney tissues were removed to evaluate biochemically, immunohistochemically and histopathologycally. There were histopathological deteriorations, rises of apoptotic cells, expressions of heat shock proteins, endoplasmic reticulum stress and inflammation markers in the MTX group. In the MTX group, Superoxide Dismutase (SOD), Total Antioxidant Status (TAS) and Catalase (CAT) levels decreased, but Total Oxidant Status TOS, Malondialdehyde (MDA) and interleukin-6 (IL6) levels increased. In addition, there was amelioration in kidney tissue in Vit B12 + MTX group compared to the MTX group. We suggest that Vit B12 can be used to reduce the toxic effects of MTX.

ABCG2 polymorphism, age and leukocyte count may contribute to oral mucositis in oncopediatric patients

The study investigated the relationship between genetic polymorphisms and the development of oral mucositis in pediatric patients undergoing chemotherapy involving methotrexate. A longitudinal study was conducted with 64 patients, and oral mucositis was evaluated by the modified Oral Assessment Guide, which aims to diagnose and classify oral mucositis. Epithelial cells were obtained by mouthwash and DNA was extracted. The polymorphisms MTHFR (rs1801133), DNMT3B (rs2424913), ABCC2 (rs717620), ABCG2 (rs2231137) and ABCG2 (rs2231142) were analyzed by PCR-RFLP method. Demographic, hematological and biochemical data were collected from medical records. Statistical analysis was performed using the SPSS software adopting a p-value of 0.05. Male sex predominated (56.2%), and the mean age was 10.8 years (± 4.9). Oral mucositis affected 65.6% of the patients, of which 61.9% developed the severe form of the disease. For the ABCG2 gene (rs2231142), the rare A allele and CA genotype were more frequent in individuals with mucositis (p= 0.02; RR = 0.60; CI = 0.387 - 0.813). The severity of the disease was mainly observed in younger patients (median = 9 years; p=0.02). Patients with severe oral mucositis presented lower leukocytes count (median = 2.150 mm3) compared to patients with the mild/moderate form (median = 4.200 mm3; p=0.03). Female patients and each 10,000-platelet increase were protective factors against the onset of oral mucositis (p=0.02). It is concluded that rs2231142 polymorphism increases the likelihood of oral mucositis and younger patients and patients with low leukocytes counts are more likely to develop severe form.

Ameliorative effect of metformin on methotrexate-induced genotoxicity: An in vitro study in human cultured lymphocytes

Methotrexate is a folic acid antagonist that has been shown to be genotoxic to normal healthy cells. Metformin is an insulin-sensitizing agent, with multiple potential pharmacodynamic profiles. The aim of the present study was to evaluate the genotoxic effect of methotrexate on DNA and the potential ameliorative effect of metformin on chromosomal damage induced by methotrexate. The present study was performed in vitro, and the frequency of chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) in human cultured lymphocytes were measured. Blood samples from five non-smoking healthy men aged 20-35 years were donated and used in the present study. Treatment of cultured blood cells with methotrexate significantly increased the number of cells with CAs (P<0.0001) and the frequency of SCEs (P<0.0001). The chromosomal injury induced by methotrexate was significantly reduced by pretreatment of the samples with metformin (P<0.0001). Importantly, the treatment of the cells with metformin alone did not affect the frequency of SCEs compared with the control group (P>0.05). Additionally, methotrexate and metformin alone, and combined, induced significant decreases in the proliferative index compared with the control group (P<0.05). In conclusion, metformin ameliorated the genotoxicity induced by methotrexate in cultured human lymphocytes.

Oral mucositis in childhood cancer patients receiving high-dose methotrexate: Prevalence, relationship with other toxicities and methotrexate elimination

BACKGROUND

Oral mucositis (OM) is one of the main adverse effects of the chemotherapeutic agent methotrexate (MTX).

AIM

To evaluate the relationship of OM with MTX metabolism time and other toxicities in childhood, cancer patients receiving high-dose of methotrexate (HD-MTX).

DESIGN

Seventy-seven childhood patients receiving HD-MTX for treatment of leukaemia, osteosarcoma or lymphoma were evaluated. MTX serum level, hepatic and renal function parameters, and presence and intensity of OM were analysed.

RESULTS

The patients were submitted to 255 cycles of chemotherapy. OM was diagnosed in 191 (74.9%) cycles. Of these, 119 (46.6%) presented ulcerative lesions. Lymphoma was associated with severe OM (P = .01). OM was associated with higher serum levels of aspartate aminotransferase (P = .006), alanine aminotransferase (P = .04) and creatinine (P = .008). Increase of one unit of total bilirubin and indirect bilirubin associated, respectively, with 11% and 39% higher prevalence of OM. For each increase of one unit of creatinine serum level, it was observed a 37% higher prevalence of OM in patients with lymphoma. No association was found between delayed excretion of MTX and OM development.

CONCLUSIONS

OM is a prevalent complication of childhood cancer patients receiving HD-MTX. Renal and hepatic toxicity could be considered risk factors for OM, especially in patients with lymphoma.

Genome wide association studies for treatment-related adverse effects of pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric hematological malignancy; notwithstanding the success of ALL therapy, severe adverse drugs effects represent a serious issue in pediatric oncology, because they could be both an additional life threatening condition for ALL patients per se and a reason to therapy delay or discontinuation with important fallouts on final outcome. Cancer treatment-related toxicities have generated a significant need of finding predictive pharmacogenomic markers for the a priori identification of at risk patients. In the era of precision medicine, high throughput genomic screening such as genome wide association studies (GWAS) might provide useful markers to tailor therapy intensity on patients' genetic profile. Furthermore, these findings could be useful in basic research for better understanding the mechanistic and regulatory pathways of the biological functions associated with ALL treatment toxicities. The purpose of this review is to give an overview of high throughput genomic screening of the last 10 years that had investigated the landscape of ALL treatment-associated toxicities. This article is categorized under: Cancer > Genetics/Genomics/Epigenetics.

Pharmacogenomics as a Tool to Limit Acute and Long-Term Adverse Effects of Chemotherapeutics: An Update in Pediatric Oncology

In the past decades, new cancer treatments have been introduced in pediatric oncology leading to improvement in clinical outcomes and survival rates. However, due to inter-individual differences, some children experience severe chemotherapy-induced toxicities or a poor clinical outcome. An explanation for the diversity in response to chemotherapy is genetic variation, leading to differences in expression and activity of metabolizing and transport enzymes as well as drug targets. Pharmacogenetic testing has emerged as a promising tool to predict and limit acute and long-term adverse effects in patients. However, in pediatric oncology, limited number of patients and a considerable diversity in study results complicate the interpretation of test results and its clinical relevance. With this review, we provide an overview of new developments over the past four years regarding relevant polymorphisms related to toxicity in pediatric oncology. The following chemotherapeutics and associated toxicities are discussed: alkylating agents, anthracyclines, asparaginase, methotrexate, platinum compounds, steroids, thiopurines, topoisomerase inhibitors, and vinca alkaloids. Our review identifies several questions regarding the role of genetic variants in chemotherapy-induced toxicities. Ambiguities in the literature stem from small population sizes, differences in (statistical) interpretation and variations in sequencing technologies as well as different clinical outcome definitions. Standardization of clinical outcome data and toxicity definitions within electronic health records combined with the increased availability of genomic sequence techniques in clinical practice will help to validate these models in upcoming years.

Prediction of mucositis risk secondary to cancer therapy: a systematic review of current evidence and call to action

PURPOSE

Despite advances in personalizing the efficacy of cancer therapy, our ability to identify patients at risk of severe treatment side effects and provide individualized supportive care is limited. This is particularly the case for mucositis (oral and gastrointestinal), with no comprehensive risk evaluation strategies to identify high-risk patients. We, the Multinational Association for Supportive Care in Cancer/International Society for Oral Oncology (MASCC/ISOO) Mucositis Study Group, therefore aimed to systematically review current evidence on that factors that influence mucositis risk to provide a foundation upon which future risk prediction studies can be based.

METHODS

We identified 11,018 papers from PubMed and Web of Science, with 197 records extracted for full review and 113 meeting final eligibility criteria. Data were then synthesized into tables to highlight the level of evidence for each risk predictor.

RESULTS

The strongest level of evidence supported dosimetric parameters as key predictors of mucositis risk. Genetic variants in drug-metabolizing pathways, immune signaling, and cell injury/repair mechanisms were also identified to impact mucositis risk. Factors relating to the individual were variably linked to mucositis outcomes, although female sex and smoking status showed some association with mucositis risk.

CONCLUSION

Mucositis risk reflects the complex interplay between the host, tumor microenvironment, and treatment specifications, yet the large majority of studies rely on hypothesis-driven, single-candidate approaches. For significant advances in the provision of personalized supportive care, coordinated research efforts with robust multiplexed approaches are strongly advised.

Spider venom administration impairs glioblastoma growth and modulates immune response in a non-clinical model

Molecules from animal venoms are promising candidates for the development of new drugs. Previous in vitro studies have shown that the venom of the spider Phoneutria nigriventer (PnV) is a potential source of antineoplastic components with activity in glioblastoma (GB) cell lines. In the present work, the effects of PnV on tumor development were established in vivo using a xenogeneic model. Human GB (NG97, the most responsive line in the previous study) cells were inoculated (s.c.) on the back of RAG^−/− mice. PnV (100 µg/Kg) was administrated every 48 h (i.p.) for 14 days and several endpoints were evaluated: tumor growth and metabolism (by microPET/CT, using ¹⁸F-FDG), tumor weight and volume, histopathology, blood analysis, percentage and profile of macrophages, neutrophils and NK cells isolated from the spleen (by flow cytometry) and the presence of macrophages (Iba-1 positive) within/surrounding the tumor. The effect of venom was also evaluated on macrophages in vitro. Tumors from PnV-treated animals were smaller and did not uptake detectable amounts of ¹⁸F-FDG, compared to control (untreated). PnV-tumor was necrotic, lacking the histopathological characteristics typical of GB. Since in classic chemotherapies it is observed a decrease in immune response, methotrexate (MTX) was used only to compare the PnV effects on innate immune cells with a highly immunosuppressive antineoplastic drug. The venom increased monocytes, neutrophils and NK cells, and this effect was the opposite of that observed in the animals treated with MTX. PnV increased the number of macrophages in the tumor, while did not increase in the spleen, suggesting that PnV-activated macrophages were led preferentially to the tumor. Macrophages were activated in vitro by the venom, becoming more phagocytic; these results confirm that this cell is a target of PnV components. Spleen and in vitro PnV-activated macrophages were different of M1, since they did not produce pro- and anti-inflammatory cytokines. Studies in progress are selecting the venom molecules with antitumor and immunomodulatory effects and trying to better understand their mechanisms. The identification, optimization and synthesis of antineoplastic drugs from PnV molecules may lead to a new multitarget chemotherapy. Glioblastoma is associated with high morbidity and mortality; therefore, research to develop new treatments has great social relevance. Natural products and their derivatives represent over one-third of all new molecular entities approved by FDA. However, arthropod venoms are underexploited, although they are a rich source of new molecules. A recent in vitro screening of the Phoneutria nigriventer spider venom (PnV) antitumor effects by our group has shown that the venom significantly affected glioblastoma cell lines. Therefore, it would be relevant to establish the effects of PnV on tumor development in vivo, considering the complex neoplastic microenvironment. The venom was effective at impairing tumor development in murine xenogeneic model, activating the innate immune response and increasing tumor infiltrating macrophages. In addition, PnV activated macrophages in vitro for a different profile of M1. These activated PnV-macrophages have potential to fight the tumor without promoting tumorigenesis. Studies in progress are selecting the venom molecules with antitumor and immunomodulatory effects and trying to better understand their mechanisms. We aim to synthesize and carry out a formulation with these antineoplastic molecules for clinical trials. Spider venom biomolecules induced smaller and necrotic xenogeneic GB; spider venom activated the innate immune system; venom increased blood monocytes and the migration of macrophages to the tumor; activated PnV-macrophages have a profile different of M1 and have a potential to fight the tumor without promote tumorigenesis.

Effects of Infliximab against Methotrexate Toxicity in Splenic Tissue via the Regulation of CD3, CD68, and C200R in Rats

Methotrexate (MTX), which has been used in clinical practice for approximately 70 years, is still widely employed in the treatment of rheumatoid arthritis (RA), psoriasis, and cancer. Although MTX toxicity causes nephrotoxicity, hepatotoxicity, bone marrow suppression, pulmonary fibrosis, and gastrointestinal damage, previous studies have not addressed splenic toxicity. This is the first study to examine the effectiveness of infliximab (INF) against MTX-induced toxicity in splenic tissues via the regulation of CD3, CD68, and C200R. We investigated the effects of MTX on macrophages and T lymphocytes in the spleen at the molecular level and examined the protective potential of the tumor necrosis factor (TNF)-α antagonist INF against MTX toxicity. Three groups of rats were set up. Group 1 received saline solution only, group 2 a single dose of MTX (20 mg/kg), and group 3 INF (7 mg/kg) before administration of a single dose of MTX (20 mg/kg). All injections were given intraperitoneally. Spleen tissues were removed 5 days after MTX administration and evaluated for CD3, CD68, and CD200R using immunohistochemical staining. Finally, the mean numerical density of CD3+, CD68+, and CD200R+ cells was estimated by a histopathologist using StereoInvestigator 8. MTX increased the numerical densities of CD3+, CD68+, and CD200R+ cells (p < 0.05). We also observed that INF reduced the numerical densities of these cells following MTX administration (p < 0.05). INF may, therefore, be a promising candidate for the prevention of the deleterious effects on spleen tissue of MTX, used in the treatment of RA and cancer.

PTS micelles for the delivery of hydrophobic methotrexate

Polyoxyethanyl-α-tocopheryl sebacate (PTS) is an amphiphilic compound with self-emulsifying properties known to form micelles. In this work, we report the production of PTS micelles for the encapsulation and delivery of a hydrophobic derivative of methotrexate, MTX di-ethylated (MTX-OEt). We optimized the micelles production by testing two different techniques: auxiliary solvent and sonication. Small and homogeneous micelles (≈40 nm) were obtained through the auxiliary solvent method performed at 30 °C and using 15 mg/mL of PTS. The produced micelles with the most promising physicochemical properties did not induce cytotoxicity when tested in normal human cells (BJ5ta cells), being considered for the encapsulation of MTX-OEt. This prodrug was achieved by Fisher esterification using ethanol, being isolated in good yield (η = 68%). MTX-OEt was efficiently encapsulated onto the produced micelles which preserved their physicochemical properties. The PTS micelles loaded with MTX-OEt, free MTX-OEt and free unmodified MTX revealed similar biological effect against cancer cells (Caco-2 cells). These results demonstrated that the biological activity of MTX is not altered after modification. The developed PTS micelles revealed a promising intracellular delivery performance with potentiality for cancer therapy.

Whole-body Imaging of Cell Death Provides a Systemic, Minimally Invasive, Dynamic, and Near-real Time Indicator for Chemotherapeutic Drug Toxicity

PURPOSE

Response to toxicity in chemotherapies varies considerably from tissue to tissue and from patient to patient. An ability to monitor the tissue damage done by chemotherapy may have a profound impact on treatment and prognosis allowing for a proactive management in understanding and mitigating such events. For the first time, we investigated the feasibility of using whole-body imaging to map chemotherapeutic drug-induced toxicity on an individual basis.

EXPERIMENTAL DESIGN

In a preclinical proof-of-concept, rats were treated with a single clinical dose of cyclophosphamide, methotrexate, or cisplatin. In vivo whole-body imaging data were acquired using ^99mTc-duramycin, which identifies dead and dying cells as an unambiguous marker for tissue injury in susceptible organs. Imaging results were cross-validated using quantitative ex vivo measurements and histopathology and compared with standard blood and serum panels for toxicology.

RESULTS

The in vivo whole-body imaging data detected widespread changes, where spatially heterogeneous toxic effects were identified across different tissues, within substructures of organs, as well as among different individuals. The signal changes were consistent with established toxicity profiles of these chemotherapeutic drugs. Apart from generating a map of susceptible tissues, this in vivo imaging approach was more sensitive compared with conventional blood and serum markers used in toxicology. Also, repeated imaging during the acute period after drug treatment captured different kinetics of tissue injury among susceptible organs in males and females.

CONCLUSIONS

This novel and highly translational imaging approach shows promise in optimizing therapeutic decisions by detecting and managing drug toxicity on a personalized basis.Toxicity to normal tissues is a significant limitation in chemotherapies. This work demonstrated an in vivo imaging-based approach for characterizing toxicity-induced tissue injury in a systemic, dynamic, and near-real time fashion. This novel approach shows promise in optimizing therapeutic decisions by monitoring drug toxicity on a personalized basis.

Determining risk of severe gastrointestinal toxicity based on pretreatment gut microbial community in patients receiving cancer treatment: a new predictive strategy in the quest for personalized cancer medicine

PURPOSE OF REVIEW

Currently, our ability to accurately predict a patient's risk of developing severe gastrointestinal toxicity from their cancer treatment is limited. Risk stratification continues to rely on traditional patient-related and treatment-related factors including age, ethnicity, sex, comorbidities, genetics, agent, dose and schedule. Although informative, these crude measures continue to underestimate toxicity risk, and hence alternative methods of risk prediction must be investigated. Given the increasing focus on the gut microbiome in driving disease, this review will provide an overview of the current literature proposing the gut microbiome as a novel predictive tool for treatment-induced gastrointestinal toxicity.

RECENT FINDINGS

Predictive gut microbial phenotypes have been identified for gastrointestinal toxicity induced by radiation and the checkpoint blocker, Ipilimumab. Each study employed slightly different methods of gut microbiome assessment; however, in all cases, separation of toxic versus nontoxic patients was achieved. No studies have investigated chemotherapy-induced gastrointestinal toxicity.

SUMMARY

The gut microbiome offers an exciting new method of risk stratification for gastrointestinal toxicity. This would enable identification of high-risk patients prior to treatment, enabling tailored treatment regimens based on personalized risk assessment and the proactive provision of supportive care measures. Based on the plasticity of the gut microbiome, methods of risk mitigation may be investigated.

[Apparent worsening of psoriasis lesions revealing methotrexate overdosage]

BACKGROUND

Methotrexate (MTX) is an antimetabolite drug used in the treatment of cancers and autoimmune diseases and frequently in dermatology for cutaneous and/or arthritic psoriasis. Toxicities due to MTX overdosage are mainly cutaneous, hepatic and hematologic. Herein, we report a case of MTX overdosage presenting as an erosive and an inflammatory flare of preexisting psoriatic plaques and with new palmar lesions.

PATIENTS AND METHODS

A 51-year-old male with a 6-year history of plaque psoriasis resistant to topical corticosteroids was started for the first time on MTX 20mg weekly. One week later, he presented with fever, general weakness and mucocutaneous ulcerations. Physical examination revealed inflammatory, erythematous and partially erosive annular plaques strictly confined to preexisting psoriatic lesions, along with keratotic psoriatic palmar plaques. Further questioning indicated that the patient was taking MTX 20mg daily. Investigations revealed neutropenia (1040/mm³) and skin histology showed prominent dystrophic keratinocytes and confirmed the diagnosis of methotrexate toxicity. Clinical and biological improvements were observed after cessation of MTX and treatment with folinic acid, IV hydration and urine alkalization.

DISCUSSION

Skin lesions due to acute MTX toxicity are rare, but they herald later-onset pancytopenia. Identification of these cutaneous lesions might enable earlier treatment initiation. The predilection of MTX toxicity for preexisting lesions or the de novo appearance of palmoplantar pustules should not lead to the erroneous diagnosis of psoriasis flare.

Clinical pharmacokinetics of methotrexate in oncology

Methotrexate is an antifolate agent used in the treatment of autoimmune diseases and various types of cancers. It is a unique antiproliferative agent because it can be administered by multiple routes with a wide variation of dosing. Methotrexate pharmacokinetics have generated numerous papers focusing on descriptive data and pharmacodynamics. Methotrexate is one of the rare anticancer agents which pharmacokinetics are routinely monitoring to control excessive toxicity when administrated at high dose (>1 g/m2). The identification of transporters involved in its disposition has permitted the understanding and the prevention of most drug interactions. Pharmacogenetic factors affecting the expression of MRP2 and OATP1B1 partly explain the interindividual variability of methotrexate clearance. The remaining challenge in methotrexate pharmacokinetics is to further understand unexplained delayed renal elimination despite the implementation of preventive measures.