Polymorphisms in methotrexate transporters and their relationship to plasma methotrexate levels, toxicity of high-dose methotrexate, and outcome of pediatric acute lymphoblastic leukemia

Systematic review: genetic polymorphisms in the pharmacokinetics of high-dose methotrexate in pediatric acute lymphoblastic leukemia patients

Variations in pharmacokinetic responses to high-dose methotrexate are essential for the prognosis and management of toxicity in the treatment of pediatric acute lymphoblastic leukemia (ALL) patients. This systematic review aimed to identify and evaluate genetic polymorphisms that are significantly associated with the pharmacokinetic parameters of methotrexate during the consolidation phase of pediatric ALL treatment. Using the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines, we systematically reviewed the literature from 2013 to 2023. The databases used were PubMed and Scopus. The outcomes of interest are the study design, patient characteristics, sample size, chemotherapy protocol utilized, pharmacokinetic parameters identified, and genetic polymorphisms implicated. We included 31 articles in the qualitative synthesis and found that the SLCO1B1, ABCB1, ABCC2, and MTHFR genes appear to play significant roles in MTX metabolism and clearance. Among these, variations in SLCO1B1 have the most significant and consistent impact on methotrexate clearance. These implicated variants may contribute to the precision and tailoring of HD-MTX treatment in pediatric ALL patients.

Comprehensive Evaluation of OATP- and BCRP-Mediated Drug-Drug Interactions of Methotrexate Using Physiologically-Based Pharmacokinetic Modeling

Methotrexate (MTX) is an antifolate agent widely used for treating conditions such as rheumatoid arthritis and hematologic cancer. This study aimed to quantitatively interpret the drug-drug interactions (DDIs) of MTX mediated by drug transporters using physiologically-based pharmacokinetic (PBPK) modeling. An open-label, randomized, 4-treatment, 6-sequence, 4-period crossover study was conducted to investigate the effects of rifampicin (RFP), an inhibitor of organic anionic transporting peptides (OATP) 1B1/3, and febuxostat (FBX), an inhibitor of breast cancer resistance protein (BCRP), on the pharmacokinetics of MTX in healthy volunteers. PBPK models of MTX, RFP, and FBX were developed based on in vitro and in vivo data, and the performance of the simulation results for final PBPK models was validated in a clinical study. In the clinical study, when MTX was co-administered with RFP or FBX, systemic exposure of MTX increased by 33% and 17%, respectively, compared with that when MTX was administered alone. When MTX was co-administered with RFP and FBX, systemic exposure increased by 52% compared with that when MTX was administered alone. The final PBPK model showed a good prediction performance for the observed clinical data. The PBPK model of MTX was well developed in this study and can be used as a potential mechanistic model to predict and evaluate drug transporter-mediated DDIs of MTX with other drugs.

Involvement of the ABCB1 C3435T Variant but Not the MTHFR C677T or MTHFR A1298C Variant in High-Dose Methotrexate-Induced Toxicity in Pediatric Acute Lymphoblastic Leukemia Patients in China

Purpose

It remains unclear whether the MTHFR C677T, MTHFR A1298C and ABCB1 C3435T genetic variants are associated with methotrexate (MTX) elimination delay and high-dose MTX (HD-MTX) toxicities in the treatment of pediatric acute lymphoblastic leukemia (ALL). The aim of our study was to analyze the potential predictive role of MTHFR C677T, MTHFR A1298C and ABCB1 C3435T in toxicities and the relationship between these variants and MTX elimination delay during HD-MTX therapy in pediatric ALL patients.

Patients and Methods

We conducted a retrospective study on ALL patients receiving HD-MTX treatment with available MTHFR C677T, MTHFR A1298C and ABCB1 C3435T genotype and 44-h plasma MTX levels. Logistic regression analyses and chi-square tests were used to assess the relationship between the variants and HD-MTX toxicities and MTX elimination delay.

Results

Genotype frequencies were in Hardy-Weinberg equilibrium. MTX elimination delay did not significantly differ between MTHFR C677T and MTHFR A1298C or ABCB1 C3435T. Leukopenia (P=0.028), neutropenia (P=0.034) and oral mucositis (P=0.023) were 6.444-fold, 4.978-fold and 9.643-fold increased, respectively, in ABCB1 C3435T homozygous genotype (TT) patients compared to wild-type (CC) patients. No significant association was found between the toxicities investigated and MTHFR C677T or MTHFR A1298C.

Conclusion

This study showed that the ABCB1 C3435T homozygous allele genotype (TT) is associated with increased MTX-related toxicities (leukopenia, neutropenia and oral mucositis). These results may help to distinguish pediatric ALL patients with a relatively high risk of MTX-related toxicities before HD-MTX infusion and optimize MTX treatment.

GENETIC PREDICTORS OF TOXIC EFFECTS OF METHOTREXATE IN CANCER PATIENTS

Today, methotrexate (MTX) is used in combination with other medicines to treat a wide range of malignancies. Despite its proven high efficacy, MTX often causes serious side effects, which may result in the need to reduce the dose of MTX or discontinue the drug altogether. This, in turn, can provoke the development of MTX resistance and cancer progression. Predicting the risk of MTX-induced toxicity is currently difficult due to the variability of pharmacokinetics and pharmacodynamics in different patients, so the scientific literature is intensively searching for potential biomarkers. Based on the data available in the current literature, we analyzed the relationship between variants in the genes encoding the key components of MTX intracellular metabolism and the MTX-induced side effects and drug response. According to the results of our work, the most studied variants are those of the SLC19A1 gene, which encodes the reduced folate carrier protein 1, and the MTHFR gene, which encodes the enzyme methylenetetrahydrofolate reductase. Studies of the effect of methylation of the promoter regions of genes on the therapeutic effect of MTX are also very promising. In conclusion, the study of molecular genetic markers of MTX toxicity is extremely relevant and necessary because it can help to avoid the effect of multidrug resistance and improve the quality of life and survival of patients.

The effect of the plasma methotrexate concentration during high-dose methotrexate therapy in childhood acute lymphoblastic leukemia

Two hundred and thirty-one acute lymphoblastic leukemia (ALL) children with 1376 high-dose methotrexate (HD-MTX) courses (3-5 g/m2) were enrolled to analyze the influence of the plasma MTX concentration (CMTX) in ALL. The 24-h target peak CMTX (C24h) was set at 33 μmol/l for low-risk (LR) and 65 μmol/l for intermediate/high-risk (IR/HR) groups. The median C24h was 42.0 μmol/l and 69.7 μmol/l for LR and IR/HR groups, respectively. MTX excretion delay was observed in 14.6% of courses, which was more frequent in IR/HR groups (56.9% vs. LR group 40.2%, p = .014) and T-ALL patients (82.6% vs. B-ALL 47.1%, p = .001). MTX-related toxicities were more common in courses with MTX excretion delay. However, survival between the patients who failed to reach the target C24h or not, with or without MTX excretion delay, was comparable. These findings suggest that, owing to the effectiveness of risk stratification chemotherapy, CMTX does not exert an independent influence on the prognosis of childhood ALL.

Pharmacogenetic aspects of efficacy and safety of methotrexate treatment in pediatric acute lymphoblastic leukemia

OBJECTIVES

To evaluate the role of ABCB1 (C3435T rs1045642, rs1128503, rs2032582, rs4148738), SLCO1B1 T521C rs4149056 genetic polymorphisms in the development of major types of methotrexate (MTX) toxicities and the occurrence of a terminal event (death, relapse) in pediatric АLL.

METHODS

The study included 124 patients diagnosed with pediatric ALL. All patients treated according to the protocols of the German BFM group (2002/2009) with high-dose (1,000, 2,000 and 5,000 mg/m2) methotrexate. MTX-related toxicities, including hematologic, hepatic and renal, were evaluated according to the common terminology criteria for adverse events version 5.0 (CTCAE v.5.0). Real-time PCR method was used to investigate polymorphisms of ABCB1 and SLCO1B1 genes. The study material was peripheral blood.

RESULTS

A competitive analysis demonstrated significant relationships between MTX ADRs. The results of the study support the existence of relationships between some ADRs and MTX kinetics. An associative analysis showed association with the development of AEs to methotrexate indicating their clinical significance from different genetic polymorphisms protein-transporters. The available results confirm the associations of the studied genes with the increased risk of high doses MTX toxic ADRs and terminal events.

CONCLUSIONS

Complementing the existing criteria for pediatric ALL risk groups with pharmacogenetic indicators will allow further individualization of therapy.

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.

Association between SLCO1B1 genetic polymorphisms and bleeding risk in patients treated with edoxaban

Since SLCO1B1 encodes the uptake transporter OATP1B1, which can influence the pharmacokinetic and pharmacodynamic profiles of edoxaban, polymorphisms in SLCO1B1 may affect the edoxaban response. This study aimed to investigate the association between SLCO1B1 gene polymorphisms and the bleeding risk in patients receiving edoxaban. We genotyped 10 single-nucleotide polymorphisms (SNPs) from the SLCO1B1 gene in patients receiving edoxaban. We also analyzed rs3842 of ABCB1 as a confounder. The odds ratio (OR) and adjusted OR (AOR) were calculated from univariate and multivariable analysis, respectively. The area under the receiver operating characteristic curve (AUROC) was constructed for the discrimination of the model. A total of 159 patients receiving edoxaban were analyzed. Overdose and rs4149056 showed significant association with bleeding complications by around 11- and 5.5-fold, respectively. Additionally, patients with the rs4149057 variant allele (C) had a 3.9-fold increased bleeding risk compared with wild-type homozygote carriers (TT), whereas rs2306283 variant homozygote (GG) carriers had a 0.27-fold reduced bleeding risk compared with wild-type allele (A) carriers. Patients with the variant-type homozygote (CC) of ABCB1 rs3842 had a higher bleeding risk than T allele carriers (AOR = 5.3 and 5.9). The final models for multivariable analyses were acceptable based on the AUROC values (> 0.70). These findings may help predict bleeding risk in patients taking edoxaban and help personalize treatment.

Novel and replicated clinical and genetic risk factors for toxicity from high-dose methotrexate in pediatric acute lymphoblastic leukemia

STUDY OBJECTIVE

Methotrexate (MTX) is a key component of treatment for high-risk pediatric acute lymphoblastic leukemia (ALL) but may cause acute kidney injury and prolonged hospitalization due to delayed clearance. The purpose of this study is to identify clinical and genetic factors that may predict which children are at risk for creatinine increase and prolonged MTX clearance.

DESIGN

We conducted a single-center, retrospective cohort study of pediatric patients with ALL who received 4000-5000 mg/m2 of MTX. Measurements We performed germline genotyping to determine genetic ancestry and allele status for 49 single nucleotide polymorphisms (SNPs) identified from the literature as related to MTX disposition. Bayesian hierarchical ordinal regression models for creatinine increase and for prolonged MTX clearance were developed.

MAIN RESULTS

Hispanic ethnicity, body mass index (BMI) < 3%, BMI between 85%-95%, and Native American genetic ancestry were found to be associated with an increased risk for creatinine elevation. Older age, Black race, and use of the intensive monitoring protocol were associated with a decreased risk for creatinine elevation. Older age, B- compared to T-ALL, and the minor alleles of rs2838958/SLC19A1 and rs7317112/ABCC4 were associated with an increased risk for delayed clearance. Black race, MTX dose reduction, and the minor allele of rs2306283/SLCO1B1 were found to be associated with a decreased risk for delayed clearance.

CONCLUSIONS

These predictors of MTX toxicities may allow for more precise individualized toxicity risk prediction.

Fluorescence-based methods for studying activity and drug-drug interactions of hepatic solute carrier and ATP binding cassette proteins involved in ADME-Tox

In humans, approximately 70% of drugs are eliminated through the liver. This process is governed by the concerted action of membrane transporters and metabolic enzymes. Transporters mediating hepatocellular uptake of drugs belong to the SLC (Solute carrier) superfamily of transporters. Drug efflux either toward the portal vein or into the bile is mainly mediated by active transporters of the ABC (ATP Binding Cassette) family. Alteration in the function and/or expression of liver transporters due to mutations, disease conditions, or co-administration of drugs or food components can result in altered pharmacokinetics. On the other hand, drugs or food components interacting with liver transporters may also interfere with liver function (e.g., bile acid homeostasis) and may even cause liver toxicity. Accordingly, certain transporters of the liver should be investigated already at an early stage of drug development. Most frequently radioactive probes are applied in these drug-transporter interaction tests. However, fluorescent probes are cost-effective and sensitive alternatives to radioligands, and are gaining wider application in drug-transporter interaction tests. In our review, we summarize our current understanding about hepatocyte ABC and SLC transporters affected by drug interactions. We provide an update of the available fluorescent and fluorogenic/activable probes applicable in in vitro or in vivo testing of these ABC and SLC transporters, including near-infrared transporter probes especially suitable for in vivo imaging. Furthermore, our review gives a comprehensive overview of the available fluorescence-based methods, not directly relying on the transport of the probe, suitable for the investigation of hepatic ABC or SLC-type drug transporters.

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.

Effects of genetic polymorphisms on methotrexate levels and toxicity in Chinese patients with acute lymphoblastic leukemia

Methotrexate (MTX) has an antitumor effect when used for the treatment of acute lymphoblastic leukemia (ALL). This study aims at evaluating the associations between 14 polymorphisms of six genes involved in MTX metabolism with serum MTX concentration and toxicity accompanying high-dose MTX. Polymorphisms in 183 Chinese patients with ALL were analyzed using TaqMan single nucleotide polymorphism genotyping assay. The serum MTX concentration was determined using homogeneous enzyme immunoassay. MTX-related toxicities were also evaluated. Renal toxicity was significantly associated with higher serum MTX concentrations at 24, 48, and 72 hours, and MTX elimination delay (P = 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively), whereas SLCO1B1 rs4149056 was associated with serum MTX concentrations at 48 and 72 hours, and MTX elimination delay in candidate polymorphisms (P = 0.014, P = 0.019, and P = 0.007, respectively). SLC19A1 rs2838958 and rs3788200 were associated with serum MTX concentrations at 24 hours (P = 0.016, P = 0.043, respectively). MTRR rs1801394 was associated with serum MTX concentrations at 72 hours (P = 0.045). Neutropenia was related to SLC19A1 rs4149056 (odds ratio [OR]: 3.172, 95% confidence interval [CI]: 1.310-7.681, P = 0.011). Hepatotoxicity was associated with ABCC2 rs2273697 (OR: 3.494, 95% CI: 1.236-9.873, P = 0.018) and MTRR rs1801394 (OR: 0.231, 95% CI: 0.084-0.632, P = 0.004). Polymorphisms of SLCO1B1, SLC19A1, ABCC2, and MTRR genes help predict higher risk of increased MTX levels or MTX-related toxicities in adult ALL patients.

Effects of SLCO1B1 on elimination and toxicities of high-dose methotrexate in pediatric acute lymphoblastic leukemia

Aim: To evaluate the association between SLCO1B1 polymorphisms and elimination/toxicities of high-dose methotrexate (MTX). Methods: SLCO1B1 rs11045879 and rs4149056 polymorphisms were retrospectively genotyped in 301 children with newly diagnosed acute lymphoblastic leukemia. MTX concentration, doses of leucovorin rescue and toxicities were recorded. Results: SLCO1B1 rs11045879C carriers (CC + CT) had higher plasma MTX levels at 96 hr, and longer MTX elimination time. The number of leucovorin rescue doses in rs4149056C carriers (CC + CT) was more than those in TT ones. Moreover, SLCO1B1 polymorphisms were associated with HDMTX toxicities including thrombocytopenia, renal toxicity and anal mucositis, but not associated with MTX level at other time points or delayed elimination. Conclusions: Our data demonstrate that genotyping of SLCO1B1 might be useful to optimize MTX therapy.

The role of OATP1B1 and OATP1B3 transporter polymorphisms in drug disposition and response to anticancer drugs: a review of the recent literature

INTRODUCTION

Members of the solute carrier family of organic anion transporting polypeptides are responsible for the cellular uptake of a broad range of endogenous compounds and xenobiotics in multiple tissues. In particular, the polymorphic transporters OATP1B1 and OATP1B3 are highly expressed in the liver and have been identified as critical regulators of hepatic eliminaton. As these transporters are also expressed in cancer cells, the function alteration of these proteins have important consequences for an individual's susceptibility to certain drug-induced side effects, drug-drug interactions, and treatment efficacy.

AREAS COVERED

In this mini-review, we provide an update of this rapidly emerging field, with specific emphasis on the direct contribution of genetic variants in OATP1B1 and OATP1B3 to the transport of anticancer drugs, the role of these carriers in regulation of their disposition and toxicity profiles, and recent advances in attempts to integrate information on transport function in patients to derive individualized treatment strategies.

EXPERT OPINION

Based on currently available data, it appears imperative that different aspects of disease, physiology, and drugs of relevance should be evaluated along with an individual's genetic signature, and that tools such as biomarker levels can be implemented to achieve the most reliable prediction of clinically relevant pharmacodynamic endpoints.

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.

Effect of Polymorphisms of ABCB1 and MTHFR on Methotrexate-Related Toxicities in Adults With Hematological Malignancies

Study of the association between single nucleotide polymorphisms (SNPs) of methotrexate (MTX) pathway genes and MTX-related toxicity in the treatment of hematological malignancies is popular. Here, we studied the association between SNPs of MTHFR and ABCB1 and MTX-related toxicity in 157 adult Chinese patients diagnosed with hematological malignancies. Patients were genotyped for MTHFR rs1801131, MTHFR rs1801133, and ABCB1 rs1045642 by fluorescence in situ hybridization. Patients with MTHFR rs1801133T allele had a significantly higher risk of hematopoietic toxicity compared with those with CC genotype (p=0.003). With respect to MTHFR rs1801131, patients with CC and AC genotypes had significantly lower frequency of hematopoietic toxicity than patients with AA genotype (p=0.044). In conclusion, we identified an important influence of the SNPs of ABCB1 and MTHFR on MTX-related hematopoietic toxicity in adults with hematological malignancies. To optimize high-dose (HD)-MTX therapy and reduce related hematopoietic toxicity, it is necessary to detect the SNPs of MTHFR and ABCB1 before initiating HD-MTX and deciding the optimal dose of MTX and duration of leucovorin rescue, according to genetic tests and disease type in adults with hematological malignancies.

Association between SLCO1B1 polymorphism and methotrexate-induced hepatotoxicity: a systematic review and meta-analysis

Reports on the association between the solute carrier organic anion transporter 1B1 (SLCO1B1) T521C polymorphism and methotrexate-induced hepatotoxicity in patients with malignancies are inconsistent. This meta-analysis evaluated the association between the SLCO1B1 T521C polymorphism and methotrexate-induced hepatotoxicity. We performed a systematic review of previous reports from the PubMed, Web of Science, and EMBASE databases, and a meta-analysis was conducted. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated to evaluate the effect of the SLCO1B1 T521C polymorphism on the occurrence of methotrexate-induced hepatotoxicity. In total, data from five studies including 465 patients were analyzed. Patients had received a high-dose methotrexate regimen (1-5 g/m2). The SLCO1B1 variant allele (C allele) carriers had a 1.9-fold higher risk of hepatotoxicity than wild-type homozygote carriers (TT; OR, 1.94; 95% CI, 1.14-3.31). This meta-analysis demonstrated that C allele carriers of the SLCO1B1 polymorphism had a higher risk of hepatotoxicity than patients with the TT genotype. The SLCO1B1 T521C polymorphism may be a useful predictor for methotrexate-induced hepatotoxicity in patients with malignancies.

Genetic Polymorphisms of Very Important Pharmacogene Variants in the Blang Population from Yunnan Province in China

Background

We aimed to enrich the pharmacogenomic information of a Blang population (BP) from Yunnan Province in China.

Methods

We genotyped 55 very important pharmacogene (VIP) variants from the PharmGKB database and compared their genotype distribution (GD) in a BP with that of 26 populations by the χ² test. The minor allele frequency (MAF) distribution of seven significantly different single-nucleotide polymorphisms (SNPs) was conducted to compare the difference between the BP and 26 other populations.

Results

Compared with the GD of 55 loci in the BP, among 26 studied populations, GWD, YRI, GIH, ESN, MSL, TSI, PJL, ACB, FIN and IBS were the top-10 populations, which showed a significantly different GD >35 loci. CHB, JPT, CDX, CHS, and KHV populations had a significantly different GD <20 loci. A GD difference of 27–34 loci was found between the BP and 11 populations (LWK, CEU, ITU, STU, PUR, CLM, GBR, ASW, BEB, MXL and PEL). The GD of five loci (rs750155 (SULT1A1), rs4291 (ACE), rs1051298 (SLC19A1), rs1131596 (SLC19A1) and rs1051296 (SLC19A1)) were the most significantly different in the BP as compared with that of the other 26 populations. The genotype frequency of rs1800764 (ACE) and rs1065852 (CYP2D6) was different in all populations except for PEL and LWK, respectively. MAFs of rs1065852 (CYP2D6) and rs750155 (SULT1A1) showed the largest fluctuation between the BP and SAS, EUR, AFR and AMR populations.

Conclusion

Our data can provide theoretical guidance for safe and efficacious personalized drug use in the Blang population.

High dose methotrexate in adult Egyptian patients with hematological malignancies: impact of ABCB1 3435C > T rs1045642 and MTHFR 677C > T rs1801133 polymorphisms on toxicities and delayed elimination

High dose methotrexate (HDMTX) is an essential agent in chemotherapeutic regimens used in various hematological malignancies in Egyptian adults. The research for the impact of gene polymorphism on HDMTX induced toxicities and delayed elimination is an important ongoing objective in many studies, variable and conflicting results produced in the past years to clarify that impact. This study aimed to investigate the role of ABCB1 3435 C > T rs1045642 and MTHFR 677 C > T rs1801133 polymorphisms on HDMTX induced toxicity outcomes and delayed elimination in Egyptian adult patients with hematological malignancies. A prospective, observational cohort study was conducted on a total of 62 Egyptian adult patients with hematological malignancies age ≥ 18-years-old. All demographic, medical, and laboratory data were continuously collected from the patients' medical files in an up-to-date follow-up in selected clinics during the period from April 2018 to March 2020. Venous blood samples were collected for the purpose of genotyping, DNA extraction, and measurement of MTX levels. All the relevant data were statistically analyzed. The studied patients' median age was 25 years old with a range of (18-62) years. Forty-six patients were males with about 74%, and 16 were females with about 26%. Eighty-nine percent of the patients diagnosed with acute lymphoblastic leukemia 'ALL', 5% of the patients had B cell non-hodgkin lymphoma 'B-NHL' and 3% diagnosed with primary central nervous system lymphoma 'PCNSL' and Burkitt's lymphoma 'BL' Hematological, hepatic, renal and gastrointestinal toxicities observed post-HDMTX were recorded with the hematological toxicities toping on all the others, also patients with delayed elimination at 72 hours post the HDMTX dose were determined. Statistical analysis revealed a significant association between ABCB1 3435 C > T rs1045642 and HDMTX delayed elimination with about 10 times higher risk among the minor allele 'T' carriers (p-value = 0.006) (odds ratio [OR]: 10.470; 95% CI: 1.961-55.904). No significant association observed between the studied gene polymorphisms: MTHFR 677 C > T rs1801133, ABCB1 3435 C > T rs1045642, and different toxicity outcomes. According to our best knowledge, this study is the first to conclude a significant association between ABCB1 3435 C > T rs1045642 gene polymorphism and HDMTX delayed elimination at 72 hours post HDMTX infusion; also, it is the first study to analyze the association between ABCB1 3435 C > T rs1045642 polymorphism with HDMTX toxicity and delayed elimination in adult Egyptian patients with hematological malignancies.

Identification of AGT and CD44 in methotrexate-resistant colorectal cancer and reversal of methotrexate-resistance

This study aims to screen out hub genes in 2 methotrexate-resistant colorectal cancer (CRC) cells (HT29 and Caco2), compared with parental CRC cells and reverse methotrexate-resistance in methotrexate-resistant CRC. GEO database and R software were utilized to analyze the gene expression profiles GSE11440 and GSE16066. Venn diagram was used to identify intersection differentially expressed genes (DEGs) between GSE11440 and GSE16066. Protein-protein interaction (PPI) was utilized to screen out central node genes. Hub genes were determined by volcano graphs, heatmaps and box plots. The functional enrichment analysis was exhibited with DAVID. The GEPIA was used to obtain survival curves to analyze association between patient prognosis and hub genes. Western blotting was used to detect the expressions of hub genes. CCK-8 assay was used to show MTX-resistant CRC cell viability following CD44 inhibitor (THIQ) and AGT inhibitor (O⁶-BG) treatments. In our results, there were 180 intersection DEGs between GSE11440 and GSE16066. CD44 and AGT were screened out as hub genes by PPI, heatmaps, volcano and box plots. In the 2 MTX-resistant CRC cells, the expressions of CD44 and AGT were up-regulated compared with parental CRC cells. The results of western blotting showed that CD44 and AGT were up-regulated in MTX-resistant HT29 and Caco2 cells compared with parental CRC cells. CCK-8 assay results showed that the combination of MTX with O⁶-BG or THIQ could significantly reduce the activity of MTX-resistant CRC cells. This research screened out CD44 and AGT in MTX-resistant CRC cells by bioinformatics and suggested that the combination of MTX with O⁶-BG or THIQ could enhance the sensitivity of MTX-resistant CRC cells to MTX. This research provides a new strategy for overcoming MTX-resistance in CRC.

The Role of Genetic Polymorphisms in High-Dose Methotrexate Toxicity and Response in Hematological Malignancies: A Systematic Review and Meta-Analysis

Objective: High-dose methotrexate (HDMTX) is a mainstay therapeutic agent for the treatment of diverse hematological malignancies, and it plays a significant role in interindividual variability regarding the pharmacokinetics and toxicity. The genetic association of HDMTX has been widely investigated, but the conflicting results have complicated the clinical utility. Therefore, this systematic review aims to determine the role of gene variants within the HDMTX pathway and to fill the gap between knowledge and clinical practice. Methods: Databases including EMBASE, PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and the Clinical Trials.gov were searched from inception to November 2020. We included twelve single-nucleotide polymorphisms (SNPs) within the HDMTX pathway, involving RFC1, SLCO1B1, ABCB1, FPGS, GGH, MTHFR, DHFR, TYMS, and ATIC. Meta-analysis was conducted by using Cochrane Collaboration Review Manager software 5.3. The odds ratios (ORs) or hazard ratios (HRs) with 95% confidence interval (95% CI) were analyzed to evaluate the associations between SNPs and clinical outcomes. This study was performed according to the PRISMA guideline. Results: In total, 34 studies with 4102 subjects were identified for the association analysis. Nine SNPs involving MTHFR, RFC1, ABCB1, SLCO1B1, TYMS, FPGS, and ATIC genes were investigated, while none of studies reported the polymorphisms of GGH and DHFR yet. Two SNPs were statistically associated with the increased risk of HDMTX toxicity: MTHFR 677C>T and hepatotoxicity (dominant, OR=1.52, 95% CI=1.03-2.23; recessive, OR=1.68, 95% CI=1.10-2.55; allelic, OR=1.41, 95% CI=1.01-1.97), mucositis (dominant, OR=2.11, 95% CI=1.31-3.41; allelic, OR=1.91, 95% CI=1.28-2.85), and renal toxicity (recessive, OR=3.54, 95% CI=1.81-6.90; allelic, OR=1.89, 95% CI=1.18-3.02); ABCB1 3435C>T and hepatotoxicity (dominant, OR=3.80, 95% CI=1.68-8.61), whereas a tendency toward the decreased risk of HDMTX toxicity was present in three SNPs: TYMS 2R>3R and mucositis (dominant, OR=0.66, 95% CI=0.47-0.94); RFC1 80A>G and hepatotoxicity (recessive, OR=0.35, 95% CI=0.16-0.76); and MTHFR 1298A>C and renal toxicity (allelic, OR=0.41, 95% CI=0.18-0.97). Since the data of prognosis outcomes was substantially lacking, current studies were underpowered to investigate the genetic association. Conclusions: We conclude that genotyping of MTHFR and/or ABCB1 polymorphisms prior to treatment, MTHFR 677C>T particularly, is likely to be potentially useful with the aim of tailoring HDMTX therapy and thus reducing toxicity in patients with hematological malignancies.

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.

Administration and Toxicity Profile of the Capizzi Interim Maintenance—Retrospective Study from a Tertiary Care Cancer Centre

Introduction The Capizzi-style methotrexate (MTX) is an integral part of acute lymphoblastic leukemia (ALL) treatment. The escalating dose of MTX originally used in the United Kingdom and Children’s Oncology Group protocols along with L-asparaginase has been modified in the Indian Childhood Collaborative Leukemia (ICiCLe) group protocol where L-asparaginase has been omitted. The data regarding the incidence of toxicities and ease of administration on the Capizzi-style interim maintenance is not robust.

Objectives We have compiled our experience with administration and toxicity profile in children with intermediate-risk ALL.

Materials and Methods A retrospective data collection of all children diagnosed with intermediate-risk ALL as per the ICiCLe risk stratification in the year 2019 was included in the analysis. Each cycle of MTX was started after ensuring an absolute neutrophil count of >750/mm3 and transaminases <2 upper limit of normal. As a unit protocol, pre- and post-MTX hydration was administered in all our children. No urine pH or midcycle biochemical parameter monitoring was done. Statistical analysis was done using Microsoft Excel and SPSS version 24 IBM Corp. in Armonk, New York, United States.

Results Forty-six children were included in the study. The median age of children in our study was 6 years (range: 1 year 2 months–12 years). Undernutrition was associated with a significant increase in toxicity (p = 0.02). Fifty-two percent of children had evidence of toxicity, elevated transaminases being the most common. There were recurring symptoms resulting in 53 episodes of toxicities overall. Incidence of toxicity was more in the early cycles (<3).

Conclusion The pre- and post-MTX hydration is an effective way to reduce toxicities with the Capizzi-style MTX and this course can be administered with ease on outpatient basis with minimal need for monitoring or admission.

Association of MTHFR and ABCB1 polymorphisms with MTX-induced mucositis in Chinese paediatric patients with acute lymphoblastic leukaemia, lymphoma or osteosarcoma-A retrospective cohort study

WHAT IS KNOWN AND OBJECTIVE

MTX pharmacology and toxicity involve several metabolizing enzymes and transporters whose functions have been suggested to be altered by genetic polymorphisms. The current study is to investigate the relationship between the genetic variation and MTX-induced adverse drug effects.

METHODS

A total of 80 paediatric patients (aged 1-14 years) were enrolled in this study. Toxicity was assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 scoring system. Genotyping was performed by MassARRAY Assay method. Data were analysed using Spss statistical package version 17.0 and Plink v1.07 software. The HWE was tested by a chi-square test. The Fisher's exact test (chi-squaretest) was used to compare the distributions of genotypes between cases and controls. OR and 95%CI were applied to evaluate the association of genetic variants with the presence of mucositis using unconditional logistic regression.

RESULTS AND DISCUSSION

Mucosal inflammatory injuries were found in 28 children. SNPs of rs1128503 (p = 0.0022, OR = 3.04, 95%CI = 1.39-6.64) and rs1045642 (p = 0.0052, OR = 2.38, 95%CI = 1.15-5.00) located in the gene of ABCB1 and SNPs of rs1801133 (p = 0.040, OR = 2.50, 95%CI = 1.06-5.88) located in the gene of MTHFR show marked impacts on the risk of developing mucositis.

WHAT IS NEW AND CONCLUSION

SNPs of ABCB1 rs1128503, rs1045642 and MTHFR rs1801133 can be risk predictor for MTX-induced mucositis in Chinese paediatric patients diagnosed with acute lymphoblastic leukaemia, lymphoma or osteosarcoma.

Novel risk factors for glucarpidase use in pediatric acute lymphoblastic leukemia: Hispanic ethnicity, age, and the ABCC4 gene

BACKGROUND

Carboxypeptidase G₂ (CPDG₂ ; glucarpidase) is a rescue drug for patients at risk for kidney injury from high-dose methotrexate (MTX). As there are no strategies for predicting patients who will require CDPG₂ , we evaluated the role of demographic, clinical, and genetic factors for CPDG₂ use.

PROCEDURE

Cases who received CPDG₂ and controls who did not were identified by chart review of acute lymphoblastic leukemia (ALL) patients who received MTX doses between 1000 and 5000 mg/m² between 2010 and 2017. We used multivariable Bayesian logistic regression to evaluate the association of CPDG₂ use with demographic and clinical variables and, on a subset of patients, with genetic ancestry and 49 single nucleotide variants previously associated with MTX toxicity.

RESULTS

We identified 423 patients who received 1592 doses of MTX. Of the 18 patients who received CPDG₂ , 17 (94%) were Hispanic. No patients who received 1000 or 2000 mg/m² of MTX received CPDG₂ . Hispanic ethnicity (odds ratio: 4.68; 95% compatibility interval: 1.63-15.06) and older age (1.87 [1.17-3.17]) were associated with receiving CPDG₂ . Of the 177 patients in the genomic cohort, 11 received CPDG₂ . Each additional G allele of rs7317112 in ABCC4 increased the odds of requiring CPDG₂ (3.10 [1.12-6.75]). Six other loci (NTRK1/rs10908521, TSG1/rs9345389, STT3B/rs1353327, SCLO1B1/rs4149056, GATA3/rs3824662, ARID5B/rs10821936) demonstrated probabilities of association between 88% and 97%.

CONCLUSION

We demonstrated that demographic characteristics, including Hispanic ethnicity and age, are associated with CPDG₂ use. Additionally, we provide evidence that inherited genetic variation is associated with risk of requiring CPDG₂ . If validated in independent populations, this information could be leveraged to develop targeted toxicity prevention strategies for children with ALL.

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.

Unstimulated salivary flow and oral streptococci in pediatric patients with hematological tumors: A longitudinal study

AIMS

To evaluate the unstimulated salivary flow (USF) and salivary colonization of total Streptococcus spp. (TS) and mutans-group (MS) in pediatric patients with hematological tumors. Correlations of salivary and microbiological changes with chemotherapy and patient-related factors were also verified.

METHODS AND RESULTS

Eligible children (n = 31) were evaluated before (control) and after (2, 5, and 10-weeks) the chemotherapy protocol was applied. Saliva samples were collected by the traditional spitting method to determine the USF (ml/min). Salivary TS and MS were determined by colony-forming units (CFU ) counts in a selective medium. The caries experience was evaluated by DMFT/dmft indexes. Data were submitted to Student's t-test, one-way ANOVA, and correlation tests (α = 0.05). The USF rate at baseline was 0.89 (±0.73) ml/min with up to 20% reduction during the follow-up and did not differ statistically during chemotherapy (p  > .05). Chemotherapy did not modify the salivary TS load (p > .05), but induced a dysbiotic shift with higher MS counts (∼ 5 fold-increase) at 10-weeks (p < .05). There is a correlation of USF with age (r = .390) and SM load with caries experience (r_s  = -.540) at 5-weeks.

CONCLUSION

Chemotherapy may promote a specific increase of mutans-group streptococci without changing the Streptococcus spp. load and unstimulated saliva flow. Correlation reinforced the need for further enlightenment about the chemotherapy mechanisms in the salivary and microbiological parameters.

Risk prediction for delayed clearance of high-dose methotrexate in pediatric hematological malignancies by machine learning

This study aimed to establish a predictive model to identify children with hematologic malignancy at high risk for delayed clearance of high-dose methotrexate (HD-MTX) based on machine learning. A total of 205 patients were recruited. Five variables (hematocrit, risk classification, dose, SLC19A1 rs2838958, sex) and three variables (SLC19A1 rs2838958, sex, dose) were statistically significant in univariable analysis and, separately, multivariate logistic regression. The data was randomly split into a "training cohort" and a "validation cohort". A nomogram for prediction of delayed HD-MTX clearance was constructed using the three variables in the training dataset and validated in the validation dataset. Five machine learning algorithms (cart classification and regression trees, naïve Bayes, support vector machine, random forest, C5.0 decision tree) combined with different resampling methods were used for model building with five or three variables. When developed machine learning models were evaluated in the validation dataset, the C5.0 decision tree combined with the synthetic minority oversampling technique (SMOTE) using five variables had the highest area under the receiver operating characteristic curve (AUC 0.807 [95% CI 0.724-0.889]), a better performance than the nomogram (AUC 0.69 [95% CI 0.594-0.787]). The results support potential clinical application of machine learning for patient risk classification.

Systematic Review of Pharmacogenetic Factors That Influence High-Dose Methotrexate Pharmacokinetics in Pediatric Malignancies

Methotrexate (MTX) is a mainstay therapeutic agent administered at high doses for the treatment of pediatric and adult malignancies, such as acute lymphoblastic leukemia, osteosarcoma, and lymphoma. Despite the vast evidence for clinical efficacy, high-dose MTX displays significant inter-individual pharmacokinetic variability. Delayed MTX clearance can lead to prolonged, elevated exposure, causing increased risks for nephrotoxicity, mucositis, seizures, and neutropenia. Numerous pharmacogenetic studies have investigated the effects of several genes and polymorphisms on MTX clearance in an attempt to better understand the pharmacokinetic variability and improve patient outcomes. To date, several genes and polymorphisms that affect MTX clearance have been identified. However, evidence for select genes have conflicting results or lack the necessary replication and validation needed to confirm their effects on MTX clearance. Therefore, we performed a systematic review to identify and then summarize the pharmacogenetic factors that influence high-dose MTX pharmacokinetics in pediatric malignancies. Using the PRISMA guidelines, we analyzed 58 articles and 24 different genes that were associated with transporter pharmacology or the folate transport pathway. We conclude that there is only one gene that reliably demonstrates an effect on MTX pharmacokinetics: SLCO1B1.

Machine learning to predict high-dose methotrexate-related neutropenia and fever in children with B-cell acute lymphoblastic leukemia

Methotrexate (MTX), an antimetabolite for the treatment of leukemia, could cause neutropenia and subsequently fever, which might lead to treatment delay and affect prognosis. Here, we aimed to predict neutropenia and fever related to high-dose MTX using artificial intelligence. This study included 139 pediatric patients newly diagnosed with standard- or intermediate risk B-cell acute lymphoblastic leukemia. Fifty-seven SNPs of 16 genes were genotyped. Univariate and multivariate analysis were used to select SNPs and clinical covariates for model developing. Five machine learning algorithms combined with four resampling techniques were used to build optimal predictive model. The combination of random forest with adaptive synthetic appeared to be the best model for neutropenia (sensitivity = 0.935, specificity = 0.920, AUC = 0.927) and performed best for fever (sensitivity = 0.818, specificity = 0.924, AUC = 0.870). By machine learning, we have developed and validated comprehensive models to predict the risk of neutropenia and fever. Such models may be helpful for medical oncologists in quick decision-making.

Incidence and risk factors for oral mucositis in pediatric patients receiving chemotherapy

PURPOSE

To investigate the incidence and risk factors for oral mucositis (OM) in patients with childhood cancer undergoing chemotherapy.

METHODS

Eight hundred and twenty-nine cycles of chemotherapy were evaluated in 112 patients with childhood cancer undergoing chemotherapy. Chemotherapy protocol, hematological, hepatic, and renal function parameters were collected and compared to presence and severity of OM, as graded by the World Health Organization (WHO) scale. Patients received counseling on oral hygiene and those who presented with OM (grade ≥1) received photobiomodulation therapy (PBMT).

RESULTS

Age ranged from 0 to 17 years (mean/SD, 8.58 ± 5.05) and fifty-one patients (45.54%) were females. The most common baseline diseases were leukemia (51%) followed by sarcomas (23%) and lymphomas (18%). Eight hundred and twenty-nine cycles of chemotherapy were evaluated, and OM was diagnosed in 527 cycles (63.57%). Higher incidence and severity of OM was observed in protocols using high-dose methotrexate (MTX-HD), MTX-HD cyclophosphamide/doxorubicin combination, and MTX-HD combined with cyclophosphamide (p <0.001). Patients with severe OM had lower levels of leukocytes (p = 0.003), hemoglobin (p = 0.005), platelets (p = 0.034), and higher levels of total bilirubin (p = 0.027), alanine aminotransferase (ALT) (p = 0.001), and creatinine (p = 0.007).

CONCLUSION

The study contributes to the elucidation of the risk factors for OM in pediatric cancer patients. Chemotherapy protocols using MTX-HD, MTX-HD associated with doxorubicin and cyclophosphamide, and MTX-HD and cyclophosphamide a have higher incidence of severe grades of OM. Other toxicities such as hematological, hepatic, and renal also developed in patients with OM.

Genetic variants associated with methotrexate-induced mucositis in cancer treatment: A systematic review and meta-analysis

Methotrexate (MTX), an important chemotherapeutic agent, is often accompanied with mucositis. The occurrence and severity are unpredictable and show large interindividual variability. In this study, we review and meta-analyze previously studied genetic variants in relation to MTX-induced mucositis. We conducted a systematic search in Medline and Embase. We included genetic association studies of MTX-induced mucositis in cancer patients. A meta-analysis was conducted for single nucleotide polymorphisms (SNPs) for which at least two studies found a statistically significant association. A total of 34 SNPs were associated with mucositis in at least one study of the 57 included studies. Two of the seven SNPs included in our meta-analysis were statistically significantly associated with mucositis: MTHFR c.677C > T (recessive, grade ≥3 vs grade 0-2, OR 2.53, 95 %CI [1.48-4.32], False Discovery Rate[FDR]-corrected p-value 0.011) and MTRR c.66A > G (overdominant, grade ≥1 vs grade 0, OR 2.08, 95 %CI [1.16-3.73], FDR-corrected p-value 0.042).

Study on Relationships of Tumor Status and Gene Polymorphism With Blood Concentration of MTX and Toxicities in 63 Pediatric Mature B Cell Lymphoma in Chinese Population

OBJECTIVE

This study investigated the relationships of tumor status (stage, renal involvement, bone marrow status, bulky disease, liver function), tumor gene polymorphism, and methotrexate (MTX) dosage (stratified by treatment group) with blood MTX levels and adverse reactions (ADR).

METHODS

We retrospectively reviewed 63 mature B cell lymphoma patients who were treated in our center. Genotyping of the MTHFR 677 and SLCO1B1 genes was carried out, and the relationships between tumor status, polymorphism of the genes, MTX level, and ADR were analyzed.

RESULTS

Altogether, 63 children were included. The mean blood MTX concentration was 0.25 ± 0.2 umol/L at 45 h. Liver dysfunction and bulky disease were both correlated with MTX level (both P < 0.05). ADRs were higher among patients with blood MTX > 0.5 mmol/l at 45 h than for the groups with lower blood MTX. The MTHFR 677 CT genotype was correlated with liver function damage (P = 0.04); the rs11045879 locus CC genotype of SLCO1B1, stage IV, and bulky disease at the time of diagnosis were correlated with 4° neutropenia (P < 0.05). Stage IV, bulky disease, leukemia stage at the time of diagnosis, and C2 treatment group were correlated with severe anemia (P < 0.05). Stage IV, bulky disease, leukemia stage, renal invasion at the time of diagnosis, and C2 treatment group were associated with severe thrombocytopenia (P < 0.05). Bulky disease and renal invasion at the time of diagnosis were associated with severe mucositis and severe infection (P < 0.05).

CONCLUSION

Taken together, our data demonstrate that gene polymorphism, MTX levels, tumor status, and treatment group might be useful to optimize MTX therapy and estimate toxicity.

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.

ABCB1 and SLCO1B1 gene polymorphisms predict methotrexate-resistant for low-risk gestational trophoblastic neoplasia

Aim: The aim of this study was to explore the effects of ABCB1 and SLCO1B1 gene polymorphisms and the methotrexate (MTX) treatment response in patients with low-risk gestational trophoblastic neoplasia (GTN). Materials & methods: Low-risk GTN patients who received MTX as a first-line single agent were enrolled. DNA was extracted from peripheral blood samples from 18 patients and assessed for ABCB1 C3435T and SLCO1B1 T521C. Results: ABCB1 C3435T and SLCO1B1 T521C polymorphisms were not associated with the MTX response or toxicity in Thai patients Conclusion: The selected ABCB1 and SLCO1B1 polymorphism do not predict the risk of MTX resistance in low-risk GTN.

The genetics of rheumatoid arthritis

RA is a chronic systemic inflammatory disease that primarily affects the small joints of the hands and feet, and results in a mean reduction in life expectancy of 3-10 years. RA is a multigene disorder with a substantial genetic component and a heritability estimate of 60%. Large-scale Genome-Wide Association Studies (GWAS) and meta-analyses have revealed common disease-associated variants in the population that may contribute cumulatively to RA pathogenesis. This review identifies the most significant genetic variants associated with RA susceptibility to date, with particular focus on the contribution of the HLA class II genes across different ethnic groups. Also discussed are the potential applications of pharmacogenomics to RA management by identifying polymorphisms associated with variation in treatment response or toxicity. The use of genetic variants to guide treatment strategy has the potential to not only reduce National Health Service costs, but also drastically improve patient experience and quality of life.

Promising genes and variants to reduce chemotherapy adverse effects in acute lymphoblastic leukemia

Almost two decades ago, the sequencing of the human genome and high throughput technologies came to revolutionize the clinical and therapeutic approaches of patients with complex human diseases. In acute lymphoblastic leukemia (ALL), the most frequent childhood malignancy, these technologies have enabled to characterize the genomic landscape of the disease and have significantly improved the survival rates of ALL patients. Despite this, adverse reactions from treatment such as toxicity, drug resistance and secondary tumors formation are still serious consequences of chemotherapy, and the main obstacles to reduce ALL-related mortality. It is well known that germline variants and somatic mutations in genes involved in drug metabolism impact the efficacy of drugs used in oncohematological diseases therapy. So far, a broader spectrum of clinically actionable alterations that seems to be crucial for the progression and treatment response have been identified. Although these results are promising, it is necessary to put this knowledge into the clinics to help physician make medical decisions and generate an impact in patients' health. This review summarizes the gene variants and clinically actionable mutations that modify the efficacy of antileukemic drugs. Therefore, knowing their genetic status before treatment is critical to reduce severe adverse effects, toxicities and life-threatening consequences in ALL patients.

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.

Cyclin D1 G870A Polymorphism: Relation to the Risk of ALL Development, Prognosis Impact, and Methotrexate Cytotoxicity

Background:

Cyclin D1 (CCND1) regulates cell cycle progression during the late G1 and S phase and takes part in methotrexate metabolism. It was hypothesized that CCND1 gene polymorphism affects acute lymphoblastic leukemia (ALL) development, prognosis and may relate to methotrexate cytotoxicity.

Subjects and methods:

This study included 50 ALL patients and 50 healthy controls, CCND1 G870A polymorphism was studied in all items using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and evaluated methotrexate cytotoxicity for ALL patients using liver function tests before and after methotrexate treatment. We followed up patients for one year to determine disease-free survival (DFS) and overall survival (OS) and its relation to the CCND1 genotype.

Results:

We found that AA genotype and A allele have a higher risk of developing ALL compared to the control group. Additionally, we found no notable association between CCND1 variant and methotrexate cytotoxicity and no role of CCND1 polymorphism in ALL prognosis.

Conclusion:

Our results suggested that CCND1 G870A polymorphism is associated with a high risk of ALL development. However, it has no role in ALL prognosis or methotrexate cytotoxicity.

Analysis of Drug Metabolizing Gene Panel in Osteosarcoma Patients Identifies Association Between Variants in SULT1E1, CYP2B6 and CYP4F8 and Methotrexate Levels and Toxicities

High-dose methotrexate is a cornerstone agent in the chemotherapeutic treatment of patients with osteosarcoma. However, patients often develop methotrexate-induced toxicities. We aim to identify determinants of methotrexate-induced toxicities in osteosarcoma patients by investigating the relation between drug plasma levels, methotrexate-induced toxicities, and germline variants in genes related to drug absorption, distribution, metabolism, and elimination. A cohort of 114 osteosarcoma patients was genotyped for 1,931 variants in 231 genes using the Drug Metabolism Enzymes and Transporters Plus array. Methotrexate plasma levels and laboratory measurements during and after high-dose methotrexate treatment concerning renal function, liver damage, and myelopoiesis to reflect toxicity outcomes were obtained. One hundred and thirteen patients and a subset of 545 variants in 176 genes passed quality control checks. Methotrexate plasma levels showed associations with creatinine, alanine aminotransferase, and hemoglobin. Genetic variant rs3736599 in the 5'-untranslated region of SULT1E1 was associated with lower 48 hour methotrexate plasma levels [coef -0.313 (95% CI -0.459 - -0.167); p = 2.60 × 10^-5]. Association with methotrexate-induced decreased thrombocyte counts was found for two intronic variants in CYP2B6 {rs4803418 [coef -0.187 (95% CI -0.275 - -0.099); p = 3.04 × 10^-5] and rs4803419 [coef -0.186 (95% CI -0.278 - -0.093); p = 8.80 × 10^-5]}. An association with increased thrombocyte counts was identified for the intronic variant rs4808326 in CYP4F8 [coef 0.193 (95% CI 0.099 - 0.287); p = 6.02 × 10^-5]. Moreover, a secondary analysis with a binary approach using CTCAE toxicity criteria resulted in a nominal significant associations (p < 0.05) for two out of three variants (rs4803418 and rs4808326). This is the first study to identify genetic variants in SULT1E1, CYP2B6, and CYP4F8 to be associated with methotrexate pharmacokinetics and toxicities. Validation of these variants in an independent cohort and further functional investigation of variants in the identified genes is needed to determine if and how they affect methotrexate plasma levels and the development of methotrexate-induced toxicities.

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.

Pharmacogenomic Markers of Methotrexate Response in the Consolidation Phase of Pediatric Acute Lymphoblastic Leukemia Treatment

Methotrexate (MTX) is one of the staples of pediatric acute lymphoblastic leukemia (ALL) treatment. MTX targets the folate metabolic pathway (FMP). Abnormal function of the enzymes in FMP, due to genetic aberrations, leads to adverse drug reactions. The aim of this study was to investigate variants in pharmacogenes involved in FMP and their association with MTX pharmacokinetics (MTX elimination profile) and toxicity in the consolidation therapy phase of pediatric ALL patients. Eleven variants in the thymidylate synthetase (TYMS), methylenetetrahydrofolate reductase (MTHFR), dihydrofolate reductase (DHFR), SLC19A1 and SLCO1B genes were analyzed in 148 patients, using PCR- and sequencing-based methodology. For the Serbian and European control groups, data on allele frequency distribution were extracted from in-house and public databases. Our results show that the A allele of SLC19A1 c.80 variant contributes to slow MTX elimination. Additionally, the AA genotype of the same variant is a predictor of MTX-related hepatotoxicity. Patients homozygous for TYMS 6bp deletion were more likely to experience gastrointestinal toxicity. No allele frequency dissimilarity was found for the analyzed variants between Serbian and European populations. Statistical modelling did not show a joint effect of analyzed variants. Our results indicate that SLC19A1 c.80 variant and TYMS 6bp deletion are the most promising pharmacogenomic markers of MTX response in pediatric ALL patients.

Adverse effects with intravenous methotrexate in children with acute lymphoblastic leukemia/lymphoma: a retrospective study

Methotrexate (MTX) forms the backbone of maintenance cycles in childhood acute lymphoblastic leukemia (ALL) chemotherapy, including interim maintenance. There is sufficient published data describing toxicities of high dose MTX (HD-MTX), but toxicities with escalating doses of MTX (Capizzi regimen) is not well documented. Capizzi regimen is thought to be relatively safe; we contend that even low escalating doses of MTX have significant toxicities. Our study intends to characterise such events with Capizzi MTX in comparison to that seen with HD-MTX. The retrospective study was conducted at a tertiary care centre of North India. We looked for the presence of six main toxicities: febrile neutropenia, thrombocytopenia, mucositis, hepatic toxicity, renal toxicity and skin toxicity from the clinical records of children with newly diagnosed acute lymphoblastic leukemia and lymphoma (intermediate and high risk disease), treated at our centre from November 2013 to July 2018. Intermediate risk ALL (IR-ALL) received Capizzi MTX, whereas high risk ALL (HR-ALL/T-NHL), received HD-MTX. Both these regimens do not use L-asparaginase. A total of 237 cycles of Capizzi escalating MTX and 151 cycles of HD-MTX (B cell: 3 gm/m² and T cell ALL/T-NHL: 5 gm/m²) during interim maintenance were studied in 93 children. Fifty-four (54) children were of IR (all B cell ALL) and 39 of HR-ALL (21 B-ALL, 18 T-ALL/T-NHL). The combined incidence of toxicities, were similar between the two groups: 68/237 cycles (28.7%) of Capizzi MTX and 45/151 cycles (29.8%) of HD-MTX (P = 0.815). However, mucositis was more commonly witnessed in the later group at 22/151 cycle (14.6%) versus 13/237 cycles (5.5%) in Capizzi MTX (P = 0.002). Nephrotoxicity and skin toxicity was seen only in the HD-MTX group. There was no difference in the severity of toxicity, graded using NCI CTCAE v 5.0, between the two groups. There was no mortality directly attributable to methotrexate toxicity (Grade V toxicity). Serum MTX levels were available in 69/151 (45.7%) cycles of HD-MTX and showed no association with toxicity in this group. Also, there was no difference in the incidence of combined toxicities between groups with (19/69 cycles) or without (26/82 cycles) available serum MTX levels in the HR group (P = 0.577). Male gender, lower baseline ANC and lower BMI had significant association with toxicity. Methotrexate related toxicity is common with both Capizzi and HD-MTX schedule in childhood ALL with a correlation of lower BMI, baseline ANC and male gender. However, it is possible to administer Capizzi as well as HD-MTX in lower middle income countries, with manageable toxicity. Further studies will be required to substantiate our findings and determine the predictors of such events.

Genetic polymorphisms analysis of pharmacogenomic VIP variants in Bai ethnic group from China

Background

The pharmacogenomics study has been widely used for the study of very important pharmacogenetic (VIP) variants among different ethnic groups. However, there is little known about the pharmacogenomics information regarding Bai family. Our study aimed to screen the polymorphism of the VIP gene in Bai nationality.

Methods

We genotyped 81 VIP variants (selected from the PharmGKB database) in the Bai population and then compared them to the other 11 major HapMap populations by chi‐square test, structure and F‐statistics (Fst) analysis.

Results

Our results indicated that rs20417 (PTGS2), rs4148323 (UGT1A), and rs1131596 (SLC19A1) were most different in Bai compared with most of the 11 populations from the HapMap data set. Furthermore, population structure and F‐statistics (Fst) analysis also demonstrated that the Bai population has the closest genetic relationship with Han Chinese in Beijing, China (CHB), followed by Japanese in Tokyo, Japan (JPT), and the farthest population from the Yoruba in Ibadan, Nigeria (YRI).

Conclusions

Our study not only presented the genotype frequency difference between the selected population of the Bai population and the other 11 populations, but also showed that the Bai population is most similar to the CHB populations, followed by JPT. These findings would contribute to the development of individualized medicine for the Bai population.

Clinical Implications of Methotrexate Pharmacogenetics in Childhood Acute Lymphoblastic Leukaemia

Background:

In the past two decades, a great body of research has been published regarding the effects of genetic polymorphisms on methotrexate (MTX)-induced toxicity and efficacy. Of particular interest is the role of this compound in childhood acute lymphoblastic leukaemia (ALL), where it is a pivotal drug in the different treatment protocols, both at low and high doses. MTX acts on a variety of target enzymes in the folates cycle, as well as being transported out and into of the cell by several transmembrane proteins.

Methods:

We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question.

Results:

This review has intended to summarize the current knowledge concerning the clinical impact of polymorphisms in enzymes and transporters involved in MTX disposition and mechanism of action on paediatric patients with ALL.

Conclusion:

In this work, we describe why, in spite of the significant research efforts, pharmacogenetics findings in this setting have not yet found their way into routine clinical practice.