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

Association of microRNA Polymorphisms with Toxicities Induced by Methotrexate in Children with Acute Lymphoblastic Leukemia

Methotrexate (MTX), a structurally related substance to folic acid, is an important chemotherapeutic agent used for decades in the treatment of pediatric acute lymphoblastic leukemia (ALL) and other types of cancer as non-Hodgkin lymphomas and osteosarcomas. Despite the successful outcomes observed, the primary drawback is the variability in the pharmacokinetics and pharmacodynamics between patients. The main adverse events related to its use are nephrotoxicity, mucositis, and myelosuppression, especially when used in high doses. The potential adverse reactions and toxicities associated with MTX are a cause for concern and may lead to dose reduction or treatment interruption. Genetic variants in MTX transport genes have been linked to toxicity. Pharmacogenetic studies conducted in the past focused on single nucleotide polymorphisms (SNPs) in the coding and 5'-regulatory regions of genes. Recent studies have demonstrated a significant role of microRNAs (miRNAs) in the transport and metabolism of drugs and in the regulation of target genes. In the last few years, the number of annotated miRNAs has continually risen, in addition to the studies of miRNA polymorphisms and MTX toxicity. Therefore, the objective of the present study is to investigate the role of miRNA variants related to MTX adverse effects.

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.

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 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.

Magnetic Molecularly Imprinted Polymers for the Rapid and Selective Extraction and Detection of Methotrexatein Serum by HPLC-UV Analysis

In this work, novel selective recognition materials, namely magnetic molecularly imprinted polymers (MMIPs), were prepared. The recognition materials were used as pretreatment materials for magnetic molecularly imprinted solid-phase extraction (MSPE) to achieve the efficient adsorption, selective recognition, and rapid magnetic separation of methotrexate (MTX) in the patients' plasma. This method was combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) to achieve accurate and rapid detection of the plasma MTX concentration, providing a new method for the clinical detection and monitoring of the MTX concentration. The MMIPs for the selective adsorption of MTX were prepared by the sol-gel method. The materials were characterized by transmission electron microscopy, Fourier transform-infrared spectrometry, X-ray diffractometry, and X-ray photoelectron spectrometry. The MTX adsorption properties of the MMIPs were evaluated using static, dynamic, and selective adsorption experiments. On this basis, the extraction conditions were optimized systematically. The adsorption capacity of MMIPs for MTX was 39.56 mgg^-1, the imprinting factor was 9.40, and the adsorption equilibrium time was 60 min. The optimal extraction conditions were as follows: the amount of MMIP was 100 mg, the loading time was 120 min, the leachate was 8:2 (v/v) water-methanol, the eluent was 4:1 (v/v) methanol-acetic acid, and the elution time was 60 min. MTX was linear in the range of 0.00005-0.25 mg mL^-1, and the detection limit was 12.51 ng mL^-1. The accuracy of the MSPE-HPLC-UV method for MTX detection was excellent, and the result was consistent with that of a drug concentration analyzer.

Is hypoalbuminemia a risk factor for high-dose methotrexate toxicity in children with acute lymphoblastic leukemia?

Background

Repeated high-dose methotrexate (HDMTX) is a critical component of contemporary childhood acute lymphoblastic leukemia (ALL) treatment regimens. Serum albumin is considered a carrier of methotrexate (MTX) in the blood. Hypoalbuminemia is not a rare finding in children with leukemia. This study aimed to investigate the relationship between pre-infusion serum albumin and possible HDMTX toxicities.

Methods

Thirty Egyptian children with ALL were consecutively enrolled in the study between May 2018 and July 2020. They were prospectively followed up while receiving HDMTX during the consolidation phase of the TOTAL study XV protocol. HDMTX was administered intravenously as a 24-h infusion every 2 weeks. Doses of 2.5 g/m2 were used for low-risk patients and 5 g/m2 for standard/high-risk patients. The Common Terminology Criteria for Adverse Events (V.4.03) was used to report the observed toxicities after HDMTX cycles. Plasma MTX levels were estimated at 24 h (MTX24) from the beginning of HDMTX infusion in the first consolidation cycle. Serum albumin level was determined before HDMTX administration, and pre-infusion hypoalbuminemia was defined when serum albumin was <3.5 g/dL.

Results

The patients’ age ranged from 2.3 to 13.3 years at diagnosis, and most of them had B cell ALL (86.7%). Overall, 120 HDMTX cycles were analyzed, equally distributed between low and standard/high risk. Grade 3–4 anemia, grades 3–4 thrombocytopenia, febrile neutropenia, and oral mucositis were significantly more frequent in HDMTX cycles with pre-infusion hypoalbuminemia than those with normal pre-infusion albumin (p=0.003, p=0.007, p=0.006, and p=0.001, respectively). In addition, pre-infusion hypoalbuminemia was significantly associated with additional hospitalization due to HDMTX toxicity (p=0.031). Most HDMTX toxicities were comparable irrespective of the MTX dose. Oral mucositis was more frequently encountered in the 2.5 g/m2 than the 5 g/m2 HDMTX cycles (46.7 vs. 26.7%, p=0.023). A significantly longer hospitalization (due to HDMTX toxicity) was observed in the 5 g/m2 HDMTX cycles (median= 7 days vs. 4 days, p=0.012).

Conclusions

Serum albumin levels should be checked before starting HDMTX cycles, especially in resource-limited settings where malnutrition is common, and serum MTX monitoring may not be available. Optimizing serum albumin levels before HDMTX may help decrease the possibility of HDMTX toxicities.

Evaluation of cytogenetic and molecular markers with MTX-mediated toxicity in pediatric acute lymphoblastic leukemia patients

PURPOSE

Pediatric acute lymphoblastic leukemia (pALL) patients have better overall survival and methotrexate (MTX) is an effective drug used in their treatment. However, the treatment-related adverse effects (TRAEs) have a bigger impact on the therapy. In this study, we have evaluated the association of polymorphisms in genes encoding proteins engaged in MTX metabolism, and the cytogenetic aberrations with TRAEs.

METHODS

A total of 115 patients between the age of 1 and 18 years (average: 6.6) under maintenance therapy were selected for the study. SLC19A1 (c.80G > A), MTHFR (c.677C > T; c.1298A > C), and TYMS (c.*450_*455del) genotypes were determined using PCR techniques and Sanger sequencing. Cytogenetic and SNP findings were analyzed for any association with the reported toxicities using odds ratio, chi-square test, multifactor dimensionality reduction (MDR) analysis for synergistic effect and, multinomial logistic regression analysis for the likelihood of adverse events.

RESULTS

Among the evaluated genetic variations, SLC19A1 (c.80G > A) was significantly associated with TRAEs (OR = 5.71, p = 0.002). Multinomial logistic regression analysis (chi-sq = 16.64, p < 0.001) and MDR analysis (chi-sq = 10.51 p < 0.001) confirmed the finding. On the other hand, no significant association was observed between adverse events and any specific cytogenetic aberration.

CONCLUSION

SLC19A1 facilitates the import of cyclic dinucleotides and reduced folates, evaluating genotypes in this gene can help in better management of patients on methotrexate treatment. Assessing a broader gene panel can help in finding more associated markers and delivering personalized medicine to the patients.

The pharmacogenomics of vincristine-induced peripheral neuropathy in pediatric acute lymphoblastic leukemia patients in Serbia - a single center experience

Introduction/Objective. Vincristine (VCR) is one of the key drugs in current treatment protocols for pediatric acute lymphoblastic leukemia (ALL). By destabilizing microtubules, VCR arrests cells in metaphase, inducing apoptosis of malignant cells. VCR also causes axonal degradation and impairment of axonal transport, which leads to VCR-induced peripheral neuropathy (VIPN). This study aimed to investigate the association of five variants in pharmacogenes involved in VCR metabolism with VIPN in Serbian ALL children. We also wanted to discover candidate pharmacogenomic markers of VIPN in Serbian population. Methods. PCR and sequencing-based methodology was used to detect variants in CYP3?5, CEP72, ACTG1, MIR3117, and MIR4481 genes. Statistical analyses were performed for investigating their association with VIPN in 56 pediatric ALL patients. Population VCR pharmacogenomics analysis of 17 pharmacogenes from in-house next-generation sequencing data was also done. Data on allele frequency distribution for the European population were extracted from public databases. Results. During the treatment, 17.86% of patients developed VIPN. Association analyses have shown that none of the genetic variants contributed to the occurrence of VIPN in our study. Population pharmacogenomics study did not reveal valid candidate pharmacovariants for VIPN. Our results suggested that pre-emptive pharmacogenetic testing for VCR is not applicable presently. Conclusion. More comprehensive approaches are needed to identify the panel of genes that could explain the VIPN development after VCR administration in ALL patients. Utilizing better designed genome-wide association studies and more robust artificial intelligence-based tools would provide a panel of pharmacogenes for pre-emptive tests of VIPN to individualize therapy for ALL in children.

Genophenotypic Factors and Pharmacogenomics in Adverse Drug Reactions

Adverse drug reactions (ADRs) rank as one of the top 10 leading causes of death and illness in developed countries. ADRs show differential features depending upon genotype, age, sex, race, pathology, drug category, route of administration, and drug–drug interactions. Pharmacogenomics (PGx) provides the physician effective clues for optimizing drug efficacy and safety in major problems of health such as cardiovascular disease and associated disorders, cancer and brain disorders. Important aspects to be considered are also the impact of immunopharmacogenomics in cutaneous ADRs as well as the influence of genomic factors associated with COVID-19 and vaccination strategies. Major limitations for the routine use of PGx procedures for ADRs prevention are the lack of education and training in physicians and pharmacists, poor characterization of drug-related PGx, unspecific biomarkers of drug efficacy and toxicity, cost-effectiveness, administrative problems in health organizations, and insufficient regulation for the generalized use of PGx in the clinical setting. The implementation of PGx requires: (i) education of physicians and all other parties involved in the use and benefits of PGx; (ii) prospective studies to demonstrate the benefits of PGx genotyping; (iii) standardization of PGx procedures and development of clinical guidelines; (iv) NGS and microarrays to cover genes with high PGx potential; and (v) new regulations for PGx-related drug development and PGx drug labelling.

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.

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.

Genetic factors involved in delayed methotrexate elimination in children with acute lymphoblastic leukemia

BACKGROUND

Delayed excretion of methotrexate can lead to life-threatening toxicity that may result in treatment cessation, irreversible organ damage, and death. Various factors have been demonstrated to influence the pharmacokinetic process of methotrexate, including genetic and nongenetic factors.

METHODS

We investigated the genetic factors primarily related to the metabolic pathway of methotrexate in children with acute lymphoblastic leukemia with delayed elimination, defined as C_44-48h ≥ 1.0μmol/L in this study. A total of 196 patients (delayed excretion group: 98; normal excretion group: 98) who received CCCG-ALL-2015 protocol after propensity score-matched analysis were included in the study. Twenty-eight target single-nucleotide polymorphisms (SNPs) were analyzed by multiplex polymerase chain reaction and sequencing, and 25 SNPs were finally included in the study.

RESULTS

The genotype distribution of SLCO1B1 rs2306283 SNP was different between the delayed and normal excretion groups. SLCO1B1 rs2306283 AA carriers had a significantly lower methotrexate C_44-48h /D ratio than GG carriers in both groups. Furthermore, compared with the normal excretion group, SLCO1B1 rs2306283 AG and GG were risk factors for developing oral mucositis (odds ratio [OR]: 2.13; 95% confidence interval [CI]: 1.11-4.08; P < .001), hepatotoxicity (OR: 2.12; 95% CI: 1.26-3.56; P < .001), and myelosuppression (OR: 1.21; 95% CI: 1.04-1.41; P = .005) in delayed excretion group.

CONCLUSIONS

The results from this study indicate the potential role of SLCO1B1 rs2306283 as a pharmacogenomic marker to guide and optimize methotrexate treatment for delayed elimination in children with acute lymphoblastic leukemia.