Comparative study on the pharmacokinetics of 7-hydroxy-methotrexate after administration of methotrexate in the dose range of 0.5-33.6 g/m2 to children with acute lymphoblastic leukemia

Concentrations of 7-hydroxy-methotrexate (7-OH-MTX) were determined in serum samples obtained after 266 infusions of methotrexate administered to 58 children with acute lymphoblastic leukemia. The dose of methotrexate (MTX) was in the range of 0.5-33.6 g/m2. Pharmacokinetic parameters (metabolic index, drug/metabolite ratio, half-life) of 7-OH-MTX and their relationship to the kinetics of methotrexate were analyzed. A great variability was observed in the extent and time-course of the metabolite formation. The concentration of the metabolite was higher than that of the parent compound at any examined time after the end of the 24 hours' infusion. The increase of 7-OH-MTX levels at the end of the methotrexate infusion was found to be proportionate to the increase of the dose of MTX. Males had significantly higher metabolite levels than did females (P less than 0.01) in the dose range of 0.5-8.0 g/m2. The age of the patients also significantly influenced the rate of the metabolite formation. The serial number of the treatment courses did not have effect on the metabolism of MTX. Dose dependency of the elimination half-life of the metabolite was found. Although a tendency was observed that patients in continuous complete remission had higher metabolite levels than those who relapsed, the difference was not significant. Further studies are needed to determine the clinical importance of 7-OH-MT.     

Pharmacokinetics of methotrexate and 7-hydroxy-methotrexate after high-dose (33.6 g/m2) methotrexate therapy

We have measured MTX and 7-OH-MTX in plasma and urine samples from a 9-year-old boy treated with six consecutive 24-h IV high-dose MTX courses (33.6 g/m2) after a relapse of ALL. The between-course pharmacokinetics of MTX and 7-OH-MTX were found to be highly reproducible. Both MTX and 7-OH-MTX elimination followed a biphasic curve, initial half-lives (t1/2(alpha] being 2.86 +/- 0.44 h and 5.14 +/- 0.46 h (mean +/- SD) and second-phase biological half-lives (t1/2(beta] being approximately 18 and 16 h, respectively. The apparent volume of distribution for MTX was 0.8 L/kg, whereas the corresponding value for 7-OH-MTX was threefold less. Since clearance of MTX was within the range reported for lower doses, the data suggest that MTX pharmacokinetics are not dose-dependent up to 33.6 g/m2.     

High-dose methotrexate therapy (6-8 g/m2) in childhood malignancies: clinical tolerability and pharmacokinetics

Five children, ages 2.5 to 12 years (mean 6.2 years), with acute lymphoblastic leukemia or non-Hodgkin's lymphoma were given 22 courses of high-dose methotrexate (HD-MTX) therapy (6-8 g/m2/24 h). No serious clinical complications were encountered, but stomatitis occurred after three (14%) of the courses. First-phase elimination half-lives (t1/2(alpha)) of MTX and 7-hydroxy-methotrexate (7-OH-MTX) after 21 infusions were 2.7 +/- 0.4 h and 6.5 +/- 1.8 h (mean +/- SD). In one course (4.5%) there was delayed systemic MTX elimination, with first-phase elimination half-lives (t1/2(alpha] for MTX and 7-OH-MTX of 4.2 and 9.9 h, respectively, and second-phase elimination half-lives (t1/2(beta)) of 43 and 58 h. Significant decreases in white blood cell count, increases in serum creatinine, and increases in alanine aminotransferase and/or aspartate aminotransferase during the first 2-6 days were present in five (23%), three (14%), and six (27%) of the courses, respectively. The regimen was tolerated well by the children.     

Influence of high-dose methotrexate therapy (HD-MTX) on glomerular and tubular kidney function

BACKGROUND: The present investigation was intended to further clarify the mechanisms involved in renal dysfunction following high-dose methotrexate (HD-MTX) treatment. PATIENTS AND METHODS: Fifty eight predominately pediatric patients [39 male, 19 female; mean age 12.3 years (range 2.2-34.1)] suffering from acute lymphoblastic leukemia (ALL, n = 28), Non Hodgkins lymphoma (NHL, n = 13), osteosarcoma (n = 8), malignant brain tumor (n = 6), or an ALL relapse (n = 3), were prospectively examined. In the course of 220 infusions of HD-MTX, glomerular and tubular renal function was determined by measuring proteinuria and glomerular filtration rate (GFR), as well as renal excretion of alpha-1-microglobulin (AMG) and N-acetyl-beta-D-glucosaminidase (NAG). It was investigated whether there were differences in MTX toxicity in dependence on the administered dose (1, 5, or 12 g/m(2) BSA), on the combination with other cytostatic agents (ifosfamide or cyclophosphamide), on the metabolism of MTX into 7-OH-MTX, and on pre-treatment with MTX. RESULTS: The administration of HD-MTX has no direct tubulotoxic effect. The disturbance in glomerular function was dose dependently and indicated by an increase in proteinuria as well as by a decrease in GFR; all changes were completely reversible and did not correlate to the metabolism of MTX to 7-OH-MTX. Increasing the number of MTX therapeutic cycles did not increase the nephrotoxicity of MTX. CONCLUSION: MTX is not directly tubulotoxic. Its side effects on glomeruli are usually without clinical relevance.     

Randomized comparison of moderate-dose methotrexate infusions to oral methotrexate in children with intermediate risk acute lymphoblastic leukemia: A Childrens Cancer Group study

Methotrexate (MTX) infusions of 500–1,000 mg/m² over 24 hours may improve survival and prevent relapse in children with acute lymphoblastic leukemia (ALL). Childrens Cancer Group (CCG) Study 139 compared weekly oral methotrexate 20 mg/m²/week (oral MTX) to MTX 500 mg/m² infused over 24 hours (IV MTX) three times during consolidation and every 6 weeks during maintenance in 164 children with intermediate-risk ALL, i.e., those patients over age 1 year with white blood cell count 10,000 to 49,999/ml and no bulky extramedullary disease. Median follow-up for CCG-139 exceeded 75 months. Thirty-four events occurred among 80 patients receiving IV and oral MTX and 36 events among 84 patients receiving oral MTX. Two children died during induction and one did not enter remission. Remission induction rate is 98%. There have been 26 marrow relapses, 11 combined marrow and extramedullary relapses, 24 CNS relapses, and five testicular or other relapses. The frequency and distribution of relapses does not differ between the two regimens. For the entire group, overall event-free survival (EFS) at 6 years is 57.9% (standard deviation = 4.0%) and actuarial survival is 80.0% (standard deviation = 3.3%). Of the 29 patients with isolated extramedullary relapse, 18 survive free of a second event, a median of 42 months from relapse. In contrast to other trials, this trial does not show that IV MTX in this dose and schedule offers an advantage over standard therapy for this group of children. © 1996 Wiley-Liss, Inc.     

Risk factors associated with delayed methotrexate clearance and increased toxicity in pediatric patients with osteosarcoma

High‐dose methotrexate (HD‐MTX; 12 g/m²) is part of standard therapy for pediatric osteosarcoma (OS). Risk factors associated with MTX toxicity in children with OS are not well defined. We investigated the association between peak MTX levels (four‐hour) and delayed MTX clearance or treatment toxicity. Information was retrieved from electronic medical records of 33 OS patients treated with HD‐MTX at Texas Children's Hospital from 2008 to 2015. We found that the four‐hour MTX level did not contribute to toxicity or delayed MTX clearance. We demonstrated that certain demographic characteristics are associated with delayed clearance and increased toxicity.     

Methotrexate content in squamous cell carcinoma of the head and neck after low-dose methotrexate

Eleven patients with squamous carcinoma of the head and neck who were scheduled for surgical resection or endoscopic biopsy of tumor received 15 mg/m² of methotrexate (MTX). Samples of tumor, normal mucosa, and plasma were obtained at surgery or endoscopy, 18-24 hours after the last MTX dose. Tissue content and plasma concentration of MTX and folate were measured using sequential radioligand-binding assays. Median MTX content was 50.0 pmol/g wet weight in tumor, 19.0 in normal mucosa, and <0.5 nM (pmol/ml) in plasma. Since dihydrofolate reductase (DHFR) content of human tumors has previously been shown to be less than 5 pmol enzyme/g wet weight, tumor MTX content exceeded expected DHFR content in all but one patient. These data support the concept that low doses of MTX saturate tumor DHFR and that, in this regard, dose escalation may have limited value. © 1994 Wiley-Liss, Inc.     

New aspects of the determination of blood methotrexate levels in leukemic children

Serum and CSF concentrations after medium dosage of methotrexate (MTX; 500 mg/m2 - 1,000 mg/m2) have been determined by an enzymatic assay during 142 infusions in children with ALL. If the dose of MTX was 500 mg/m2 MTX concentrations in CSF were under 10(-6) M/l in 40% of the treatments but only in 22%, when the dose was increased to 1,000 mg/m2. The systemic clearance of MTX was found to be increased significantly by the 2nd MTX treatment in children who relapsed thereafter. Such a phenomenon was not observed in children who continued in remission. The relapse free survival of children, whose MTX-clearance remained constant by the 2nd MTX treatment was significantly longer. No serious MTX toxicity has been observed in our patients.     

Degradation and clearance of methotrexate in children with osteosarcoma receiving high-dose infusion

Plasma methotrexate (MTX) concentrations were quantitated in 34 patients after 127 high-dose (35–350 mg/kg) infusions with citrovorum factor rescue. Significant linear correlations have been obtained between methotrexate dosage and concentrations in plasma at 6 and 24 hours after the initiation of the therapy. However, similar trends have not been observed when 48- and 72-hour samples were analyzed. Clinical toxicity was not serious when the methotrexate level in plasma was < 4.5 × 10^?6 M at 48 hours after the start of a six-hour infusion in children. A minimal four-hour steady-state methotrexate plasma level can be maintained during a six-hour infusion. Children excrete methotrexate at a faster rate than adults; the half-life of MTX during the first phase of plasma clearance curve is one hour shorter in children. Urinary analyses have indicated that substantial methotrexate is metabolized. The chemical nature of these components has not been identified. Further, the urinary metabolic profiles varied among patients.     

Morning steroid profile in children with congenital adrenal hyperplasia under different hydrocortisone schedules

We studied 13 children with 21-hydroxyalse deficiency to explore the immediate potential suppressive effect of hydrocortisone dose schedule on the adrenal cortex. They were given 20 mg/m² daily in a controlled trial. After random administration of a greater dose in the morning (7 patients) or at night (6 patients), we measured plasma levels of 17-hydroxyprogesterone, testosterone, and androstenedione at times-24, 0, 2, 4, and 6h. Considerable fluctuation of the steroid levels, unrelated to the drug intake, was observed. There was no statistically significant differences between the “morning dose” and “night dose” groups for any steroid. We conclude that; (i) the greater night dose did not avoid the 17-hydroxyprogesterone morning peaks, and (ii) the variation in plasma steroid levels is so marked that a single morning sample is unreliable to reflect the degree of adrenal suppression.     

High-dose methotrexate therapy of childhood acute lymphoblastic leukemia: lack of relation between serum methotrexate concentration and creatinine clearance.

BACKGROUND: The objectives of this study were: (1) to analyze the relation of serum methotrexate (MTX) concentration with creatinine clearance, (2) to compare the leucovorin rescue dose administered to the patients based on creatinine clearance, with the one calculated according to serum MTX levels, and (3) to determine MTX-related toxicity. PROCEDURE: Thirty children with high-risk non-B acute lymphoblastic leukemia (ALL) treated according to the national protocol (PINDA 92) based on ALL BFM 90, were randomized to receive consolidation with four doses of either 1 or 2 g/m(2) MTX as a 24-hr infusion, at 2-week intervals (group M1 and M2, respectively). Serum MTX concentrations were measured at 24, 42, and 48 hr after beginning the infusion and were analyzed retrospectively. The creatinine clearance was calculated after 12-hr intravenous hydration prior to each MTX dose. Leucovorin dosage was adjusted according to creatinine clearance. RESULTS: Serum MTX concentrations at 24, 42, and 48 hr after starting the infusion were not related to creatinine clearance in both treatment groups. Leucovorin rescue administered according to creatinine clearance was excessive in 43% in group M1 and in 51% in group M2, as compared to the dose calculated according to serum MTX levels. No serious clinical complications were observed. CONCLUSIONS: These results suggest that creatinine clearance is not a good parameter to calculate leucovorin rescue. MTX-related toxicity in this group of patients receiving a dose of 1 or 2 g/m(2) and rescued with leucovorin without monitoring serum MTX levels was acceptable.     

Plasma methotrexate, red blood cell methotrexate, and red blood cell folate values and outcome in children with precursor B-acute lymphoblastic leukemia: a report from the Children's Oncology Group

Plasma steady state methotrexate (MTX) level and red blood cell (RBC) MTX and folate concentrations were evaluated in 1124 children with newly diagnosed acute lymphoblastic leukemia enrolled in the Pediatric Oncology Group studies 9005 (lower risk; Regimens A and C) and 9006 (higher risk; Regimen A). These regimens included intermediate-dose MTX (1 g/m) given as a 24 hours infusion every other week for 12 doses during intensification. Plasma MTX level was evaluated at the end of MTX infusions. RBC MTX and folate concentrations were measured at the end of intensification. The 5 year continuous complete remission was 76±1.4% versus 85±3.0% for those patients with steady state MTX levels less than or equal to and greater than 14 μM, respectively (P=0.0125). Hispanic children had significantly reduced median steady state MTX levels, 8.7 μM, compared with non-Hispanic children, 9.95 μM (P=0.0015), but this did not correlate with a difference in outcome. Neither RBC MTX, RBC folate, nor the RBC MTX:folate ratio identified children at increased risk of failure.     

Biopterin and neurotransmitter amine metabolism in children with acute lymphoblastic leukemia receiving methotrexate therapy

To test the hypothesis that some of the neurologic sequelae of treatment for acute lymphoblastic leukemia (ALL) might be related to abnormalities in biopterin metabolism associated with methotrexate (MTX) therapy, total biopterin levels in cerebrospinal fluid (CSF) and plasma, and homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA) were measured in a cross-sectional study of 80 children with ALL. For comparison, biopterins were also measured in a group of children of similar age undergoing investigation for neurologic disease. In children with ALL studied before therapy, no significant difference was found between the means of plasma biopterin or CSF biopterin concentrations and the means in the control group. In children receiving MTX, plasma biopterin values were higher in the group given maintenance therapy than in children observed before treatment. CSF levels were significantly increased only in those patients who had completed 2 years of maintenance therapy. CSF concentrations of HVA and 5HIAA in patients with ALL who had received no treatment (median values 52 and 18 ng/ml, respectively) showed a wide scatter and were inversely related to age. In patients receiving MTX, concentrations of these metabolites were higher than in the untreated group, again reaching a peak in patients just completing 2 years of treatment (median HVA 110 ng/ml, 5HIAA 34 ng/ml). These results provide no support for the idea that neurotransmitter amine deficiency occurs in children with ALL receiving MTX, and indicate, rather, that amine and biopterin synthesis increases in such patients.     

High-dose methotrexate improves clinical outcome in children with acute lymphoblastic leukemia: St. Jude Total Therapy Study X

High-dose methotrexate (HDMTX, 1,000 mg/m2) and cranial irradiation/sequential chemotherapy (RTSC) were compared for ability to extend complete remission durations in children with acute lymphoblastic leukemia (ALL). Three hundred thirty patients were enrolled in the study, according to our criteria for standard-risk ALL: a leukocyte count less than 100 X 10(9)/L, no mediastinal mass, no leukemic involvement of the central nervous system (CNS), and blast cells lacking sheep erythrocyte receptors and surface immunoglobulin. Prednisone-vincristine-asparaginase induced complete remissions in 95% of the patients, who were then randomized to receive either HDMTX (n = 154) or RTSC (n = 155). HDMTX was administered with intrathecal MTX for the first 3 weeks following remission induction, and then every 6 weeks with daily mercaptopurine (MP) and weekly oral MTX for a total of 18 months. The RTSC regimen consisted of 1,800 cGy cranial irradiation and intrathecal MTX for 3 weeks, followed by MP/MTX, cyclophosphamide/doxorubicin, and teniposide/cytarabine administered sequentially over 18 months. The final 12 months of treatment for both groups was MP and oral MTX; all patients received intrathecal MTX every 12 weeks. With a median follow-up of 5 years, complete remission durations have been significantly longer among children treated with HDMTX, compared with RTSC (P = .049) or historical institutional control regimens (P = .002). Approximately 67% of the patients receiving HDMTX and 56% of those receiving RTSC are expected to be in continuous complete remission at 4 years. Overall, isolated CNS relapse rates were similar (P = .17) in the two treatment groups, although by newer risk criteria cranial irradiation could be expected to provide better protection in patients with an unfavorable prognosis. These findings indicate that addition of intermittent HDMTX infusions to conventional chemotherapy is an effective method for extending complete remissions in children with ALL.     

Low-dose methotrexate in the treatment of severe juvenile rheumatoid arthritis and sarcoid iritis.

OBJECTIVE: To assess the efficacy of low-dose oral methotrexate (MTX) therapy for children with severe iritis. METHODS: MTX in a weekly dose of 7.25 to 12.5 mg/m2 was administered orally to four patients (two with juvenile rheumatoid arthritis [JRA] and two with sarcoidosis) with severe iritis not adequately controlled by topical and systemic corticosteroid therapy. The treatment was initiated with half of the total dose and increased every 2 weeks until the final dose was reached. Iritis was graded from 0 to +4 according to the density of cells in the anterior chamber of the eye. RESULTS: There were three girls and one boy with a mean age of 10.5 years. Two patients were African American and two were Caucasian. The mean age at onset of iritis was 6 years. The mean duration of MTX therapy was 28.8 months. Significant improvement was noted in two of the four patients in ocular inflammation, demonstrated by reduction of cell density from +4 to +1. Two patients had a mild improvement of the iritis. However, corticosteroids were significantly reduced in all patients. One patient was completely off steroids within 30 months of MTX therapy. In the remaining three cases, the steroid dose was successfully tapered from 0.82 mg/kg/d to 0.15 mg/kg/d (mean doses) within a mean duration of 20 months. No side effects were observed with MTX therapy. CONCLUSION: Low-dose MTX therapy was effective and safe, and displayed steroid-sparing properties in four children with severe iritis.     

Association of ABCC2 with levels and toxicity of methotrexate in Malaysian Childhood Acute Lymphoblastic Leukemia (ALL)

Abstract

Studies had shown that genetic polymorphism plays a significant role in the pharmacokinetics and pharmacodynamics variation of high dose methotrexate (MTX), 5000?mg/m² regimen. The objective of this study was to investigate the genetic variations associated with the serum level and toxicity of MTX in Malaysian children with acute lymphoblastic leukemia (ALL). Thirty-eight patients were genotyped for rs717620 (ABCC2), rs4948496 (ARID5B), rs1801133 (MTHFR) and rs4149056 (SLCO1B1). Serum levels of MTX at 48?h post 24?h of intravenous infusion were analyzed by high-performance liquid chromatography-mass spectrometry. The ABCC2 genotype was significantly associated with the serum levels of MTX at 48?h after treatment (p?=?0.017). Patients with CT and TT of rs717620 (ABCC2) and TC and CC of rs4948496 (ARID5B) were significantly associated with leukopenia grade I–IV (Fisher Exact Test; p?=?0.03 and 0.02, respectively). The three most common MTX related toxicities were leukopenia (60.5%), increased alanine aminotransferase enzyme (47.4%), and thrombocytopenia (47.4%). Our results demonstrate that by prescreening of patients for ABCC2 and ARID5B associated with the serum levels and adverse effects of MTX would identify patients at risk and therefore help a pediatric oncologist to personalize chemotherapy drugs for precision health.     

Oral methotrexate and alternate-day prednisone for low-risk langerhans cell histiocytosis

Many treatments for low-risk Langerhans cell histiocytosis (LCH) involve unpleasant side-effects or risks of late effects. To provide treatment with minimal toxicity and no known risk of late effects, we have used oral alternate-day prednisone (PDN, 40 mg/sq.m./day) and weekly methotrexate (MTX, 20 mg/sq.m. once weekly) in a series of 13 children with 17 episodes of LCH. Patients were monitored with monthly physical examinations, blood counts and chemistry panels, and radiographs and scans obtained at the treating physician's discretion. Patients who responded had the prednisone tapered and MTX discontinued after three months of treatment. Recurrences while treatment was being tapered, or after its discontinuation, were managed with resumption of MTX and PDN. Treatment was successful in 16 of the 17 episodes, meaning that symptoms resolved and abnormal physical or radiographic findings improved. Symptomatic relief occurred in two weeks or less in 14 of 17 episodes; objective improvement generally occurred within one month, and in all cases by three months. The median duration of treatment was 5 months. Toxicity was limited to slight, transient elevations in hepatic enzymes in three patients. We conclude that oral chemotherapy with alternate-day PDN and weekly MTX is effective and non-toxic in patients with low-risk LCH. © 1995 Wiley-Liss, Inc.     

Progression of methotrexate-induced leukoencephalopathy in children with leukemia

From 1972 - 1974, 228 children began treatment for acute lymphocytic leukemia and were prospectively assessed for neurologic complications. After CNS irradiation (2,400 rad) and intrathecal methotrexate (MTX), they received weekly intravenous maintenance therapy with MTX alone (40–60 mg/m²; 20 patients) or MTX (10-30 mg/m²) with other drugs (208 patients). Signs of leukoencephalopathy appeared in 11 children (nine without CNS leukemia) after 4-15 months of IV MTX alone, and included lethargy, seizures, spasticity, paresis, drooling, and dementia. Before or during the clinical onset, EEG frequencies slowed (all ten patients tested). Radionuclide scans showed periventricular accumulation of ^99mTc (9/11 patients) and remained abnormal for ≥ six months in eight patients. Cranial computed tomograms or neuropathology findings (five patients each) demonstrated leukoencephalopathy (nine patients) and radiation-related microangiopathy (ten patients). Severe neurologic and neuropsychologic dysfunctions were present in four long-term survivors.     

Sequential chemotherapy of advanced colorectal cancer with standard or high-dose methotrexate followed by 5-fluorouracil

Thirty patients with advanced measurable colorectal cancer were randomized to receive either methotrexate (MTX) 200 mg/m² or 40 mg/m², followed in four hours by 5-fluorouracil (5-FU) 600 mg/m². Patients receiving the higher dose MTX were given leucovorin rescue 24 hours later. Eight of 13 patients treated with 200 mg/m² MTX + 5-FU developed severe hematologic toxicity, leading to two toxic deaths. In addition, 9/13 developed mild azotemia, and three patients had severe gastrointestinal toxicity. No patients with prior chemotherapy responded to either regimen. Among those without prior chemotherapy, there were two of six and three of eight partial responses, respectively, in the 200 mg/m² and 40 mg/m² MTX regimens. Sequential 200 mg/m² MTX followed by 5-FU after four hours has unacceptable toxicity. Sequential treatment with standard dose MTX + 5-FU is tolerable and merits further study.     

Factors associated with response to methotrexate in systemic-onset juvenile chronic arthritis

We retrospectively investigated, in 19 children with systemic-onset juvenile chronic arthritis (SoJCA), the possible influence on the outcome of methotrexate (MTX) therapy of several independent variables, including age at onset of juvenile chronic arthritis, disease duration and severity of the disease at baseline. The dosage of MTX ranged from 7.5 to 11.O mg/m*/week (median 9.3 mg/m²/week) and was given as a single, oral weekly dose. After 6 months of treatment, 12 (63%) patients were judged as responders on grounds of a 50% reduction in the number of joints with active arthritis and/or an articular severity score; 7 (37%) did not respond to therapy. When the baseline values of the selected variables were compared, we found that the responder group had, with respect to the non-responder group, a lower percentage of radiographic lesions ( p < 0.005), a shorter duration of the disease ( p < 0.05) and a lower number of joints with limitation of motion ( p < 0.01), functional limitation score ( p < 0.05) and articular severity score ( p < 0.05). A threshold value of disease duration of two years and the presence/absence of radiographic lesions gave a correct classification with respect to the treatment outcome of 73.7% and 83.3%, respectively. The predictive value of these two variables was confirmed by a multivariate analysis. We conclude that earlier treatment with MTX, possibly before the appearance of radiographic changes, may favourably influence the outcome of MTX treatment in those patients with SoJCA who require a second-line drug.