Methotrexate pharmacogenetics in Uruguayan adults with hematological malignant diseases

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 effects of genetic polymorphism on toxicity and pharmacokinetics of methotrexate in Egyptian adult patients with leukaemia or lymphoma

Polymorphisms in genes coding folate-metabolising enzymes might alter the pharmacokinetics and sensitivity for methotrexate "MTX".The aim of the study aimed to investigate the influence of MTHFR C677T, DHFR19 Ins/del, GGH -401 C > T, and MTR A2756G polymorphisms on MTX toxicity and pharmacokinetics in Egyptian patients with Acute lymphoblastic leukaemia (ALL) or Non-Hodgkin lymphoma (NHL).Fifty adult Egyptian patients with ALL and NHL, treated with high dose MTX, were prospectively enrolled in the study. Clinical and biochemical data was collected objectively from medical records after each cycle of MTX. Plasma concentrations of MTX were measured after 72 h of initiation of infusion. Genotyping was done with a PCR-ARMS and PCR-RFLP assays.The MTHFR C677T T variants significantly increased the risk of leukopoenia, whereas the genotype MTHFR 677 C > T TT significantly associated with lymphocytopenia, thrombocytopenia, and anaemia. The genotype GGH-401 TT was significantly correlated with anaemia. Plasma MTX level was significantly higher in patients with MTR A2756G G variants.MTHFR polymorphism played the main role in MTX toxicities. The pharmacokinetics of MTX was affected by MTR polymorphism. GGH mutation was mainly concerned with anaemia. Pharmacogenetic testing are recommended to optimise MTX therapy.

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.

Alternative Methotrexate Oral Formulation: Enhanced Aqueous Solubility, Bioavailability, Photostability, and Permeability

The poor aqueous solubility and/or permeability and thereby limited bioavailability largely restricts the pharmaco-therapeutic implications of potent anticancer drugs such as methotrexate (MTX). Furthermore, MTX’s inherently unstable nature makes it difficult to develop a viable oral formulation. In this study we developed the spray-dried amorphous inclusion complexes of MTX with native β-cyclodextrin (β-CD) and its derivatives, namely HP-β-CD, M-β-CD, and DM-β-CD to enhance the aqueous solubility, photostability, permeability, and oral bioavailability of MTX in rats. Our findings show that the 1:1 stoichiometry ratio of MTX and CDs improves the aqueous solubility, stability, and pharmacokinetic profiles of the drug, the better results being obtained particularly with DM-β-CD as a host, which has a higher complexation ability with the drug compared to other β-CDs. Specifically, the pharmacokinetic analysis demonstrated 2.20- and 3.29-fold increments in AUC and Cmax, respectively, in comparison to free MTX. Even though the absorptive permeability of MTX and MTX/DM-β-CD inclusion complexes was similar, the efflux of the absorbed MTX from ICs was significantly lower compared to the free MTX (4.6- vs. 8.0-fold). Furthermore, the physicochemical characterization employing SEM, DSC, and PXRD confirmed the transformation of crystalline MTX to its amorphous state. In solution, ¹H NMR studies revealed that MTX embedded into the DM-β-CD cavity resulting in both H-3 and H-5 chemical shifts implied the presence of intermolecular interaction between the drug and CD moiety. It was, therefore, evident that an MTX IC could be a successful oral formulation technique, preventing MTX degradation and enhancing its pharmacologically relevant properties.

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.

Improved Bioavailability and High Photostability of Methotrexate by Spray-Dried Surface-Attached Solid Dispersion with an Aqueous Medium

Low aqueous solubility and poor bioavailability are major concerns in the development of oral solid-dosage drug forms. In this study, we fabricated surface-attached solid dispersion (SASD) to enhance the solubility, bioavailability, and photostability of methotrexate (MTX), a highly lipophilic and photo-unstable drug. Several MTX-loaded SASD formulations were developed for spray-drying using water as the solvent, and were investigated for their aqueous solubility and dissolution kinetics. An optimized ternary SASD formulation composed of MTX/ sodium carboxymethyl cellulose (Na-CMC)/sodium lauryl sulfate (SLS) at 3/0.5/0.5 (w/w) had 31.78-fold and 1.88-fold higher solubility and dissolution, respectively, than MTX powder. For SASD, the in vivo pharmacokinetic parameters AUC and C_max were 2.90- and 3.41-fold higher, respectively, than for the MTX powder. Solid-state characterizations by differential scanning calorimetry and X-ray diffraction revealed that MTX exists in its crystalline state within the spray-dried SASD. The MTX-loaded SASD formulation showed few physical changes with photostability testing. Overall, the results indicate that the spray-dried MTX-loaded SASD formulation without organic solvents enhances the solubility and oral bioavailability of MTX without a significant deterioration of its photochemical stability.

Synthesis, anticancer evaluation and molecular docking studies of methotrexate's novel Schiff base derivatives against malignant glioma cell lines

Recent years have witnessed advancement in cancer research that has led to the development of improved cytotoxic therapies with reduced side effects. Methotrexate (MTX) is a commonly used anticancer drug having robust activity, but with serious side effects. Several derivatives of MTX have been reported by modification at different sites to reduce its side effects and enhance efficacy. The current work describes the development of active MTX Schiff base derivatives by treating MTX with several aldehydes viz 2-chlorobenzaldehyde, 3-nitrobenzaldehyde, 5-chloro-2-hydroxybenz-aldehyde, 2-hydroxy-5-nitrobenzaldehyde, 2-thiocarboxyaldehyde, trans-2-pentenal and glutaraldehyde. Newly synthesized derivatives were evaluated for their anticancer potential against human malignant glioma U87 (MG-U87) cell lines at different concentrations of 200 μM, 100 μM, 50 μM, 25 μM, 12.5 μm, 6.25 μm and 0 μM. MTX derivatives with 2-Chlorobenzaldehyde (IC₅₀ ∼100 μM), 2-Thiocarboxyaldehyde (IC₅₀ <200 μM) and 2- Pentenal (IC₅₀ ∼250 μM) showed much better activity at 100 µM compared to 400 µM concentration of MTX. Molecular docking studies were performed that showed a good correlation with the results obtained from in vitro experiments. The excellent agreement between molecular modeling and growth inhibition assay shows that the binding mode hypothesis is justly close to the experimentally biological values, therefore, may prove helpful for further lead optimization and clinical trials.Communicated by Ramaswamy H. Sarma.

Involvement of C677T MTHFR variant but not A1298C in methotrexate-induced toxicity in acute lymphoblastic leukemia

BACKGROUND

Methotrexate (MTX) is a key drug in acute lymphoblastic leukemia (ALL) treatment; it inhibits DNA replication by blocking the conversion of 5, 10 Methylenetetrahydrofolate to 5-methylene tetrahydrofolate by methylenetetrahydrofolate reductase (MTHFR). Variants of the Methylenetetrahydrofolate reductase (MTHFR) and MTX related toxicities were largely investigated in several populations, nevertheless, the results are conflicting.

OBJECTIVE

This study aimed to assess the prevalence of MTHFR SNVs: C677>T and A1298>C in Tunisian patients with ALL and the relation to the frequency of drug-induced complications.

METHODS

28 ALL patients were included in the study. They were treated according to EORTOC, in which a high dose of MTX (HDMTX) was prescribed. A toxicity score (ST) is calculated for each patient, summing the grades of toxicities. Genotyping of MTHFR variants was done with a PCR-based restriction fragment length polymorphism assay.

RESULTS

The toxicity's score (TS) was higher with C677T variant compared to wild genotype (C677C) (TS = 4; IC95% [-2.65-13.32] versus TS = 2.5; IC95% [1.65-4.55], respectively; p = 0.2); but lower with the A1298C mutation compared to those with the wild genotype (A1298A) (TS = 2.5; IC95% [0.48-4.77], versus TS =3; IC95% [1.9-5.69], p = 0.4). HDMTX-related toxicity is associated with the 677CT genotype in ALL patients (RR = 1.41, p = 0.2); not for the A1298C [OR = 0.46, [0.08-2.61], p = 0.18].

CONCLUSION

Our preliminary findings highlight the impact of the C677T variant of MTHFR, but not the A1289C; in HD-MTX chemotherapy-related adverse effects in younger Tunisian ALL.

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.

Folate pathway genetic polymorphisms modulate methotrexate-induced toxicity in childhood acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is one of the major malignancies affecting children in Jordan. Methotrexate (MTX) is the cornerstone of chemotherapy for ALL, and works by targeting enzymes involved in the folate pathway. We hypothesize that genetic polymorphisms of the folate pathway are associated with MTX toxicity in children with ALL.

METHODS

A total of 64 children with ALL were included in this study; 31 (48.4%) boys and 33 (51.6%) girls aged 2-16 years. The folate pathway genes were genotyped using polymerase chain reaction followed by sequencing and studying the association between genetic polymorphisms and MTX toxicity.

RESULTS

The immunophenotype was B-lineage in 55 patients (85.9%) and T-lineage in nine patients (14.1%). All genetic polymorphisms, except for dihydropyrimidine dehydrogenase polymorphisms, were associated with hematological toxicities and did not appear to precipitate any non-hematological adverse events. Patients with ALL carrying dominant alleles of methylene tetrahydrofolate (MTHFR) C677T and dihydrofolate reductase 19 bp deletion were at a higher risk of developing severe leucopenia [OR (95% CI) = 4.5 (1.2-17), p = 0.03; 5.4 (1.6-17.8); p = 0.006] while minor allele carriers of MTHFR A1298C were more likely to develop neutropenia [OR (95% CI) = 6.1 (1.3-29.5); 0.04]. Furthermore, dominant allele carriers of thymidylate synthase 1494 del6 were at a higher risk of developing neutropenia [OR (95% CI) = 6 (1.2-31.1); p = 0.04].

CONCLUSION

Genetic polymorphisms of the folate pathway may modulate MTX-induced toxicity in childhood ALL.