Methotrexate--the rapidly acting drug

Methotrexate Decreases Tenofovir Exposure in Antiretroviral-Suppressed Individuals Living With HIV

BACKGROUND

To mitigate increased risk of premature cardiovascular disease in antiretroviral therapy (ART) suppressed adults living with HIV (PWH), low-dose methotrexate (LDMTX) was evaluated in a multicenter randomized placebo controlled clinical trial of 176 PWH taking various ART regimens (ACTG A5314). Given shared methotrexate (MTX) and tenofovir (TFV) pharmacokinetic (PK) pathways, a substudy was conducted to investigate whether LDMTX alters TFV exposure.

METHODS

Adults virally suppressed on ART for >24 weeks were randomized to LDMTX or placebo. The first 66 participants taking a tenofovir disoproxil fumarate-containing regimen underwent intensive PK sampling over 24 hours after the second dose of LDMTX 10 mg or placebo. TFV and MTX levels were quantified using validated mass spectrometry methods. TFV PK between LDMTX and placebo groups were compared and MTX PK was characterized.

RESULTS

Forty-eight participants completed this substudy (n = 20 on LDMTX and 28 on placebo). Baseline characteristics were balanced except for protease inhibitor (PI)-use (25% in LDMTX and 43% in placebo groups). For TFV, AUC6 (primary endpoint), and AUC24,imputed, Cmax, and Cmin (secondary endpoints) were on average 22%, and 24%, 27%, and 31% less in the LDMTX versus placebo groups, with reductions in secondary endpoints reaching statistical significance. Additional analyses suggested a greater reduction in the absence of PI although not significant.

CONCLUSION

Lower TFV AUC24,imputed and Cmax indicates that LDMTX reduces TFV exposure in PWH. However, this change was modest, not warranting a change in TFV dosing at this time. Further studies of TFV PK with LDMTX, especially without PI co-administration, are warranted.

Absence of Pharmacokinetic Interactions between the Bruton's Tyrosine Kinase Inhibitor Fenebrutinib and Methotrexate

Fenebrutinib (GDC-0853) is an orally administered small molecule inhibitor of Bruton's tyrosine kinase being investigated for treatment of rheumatoid arthritis in patients with inadequate responses to methotrexate (MTX). This study interrogated the potential for pharmacokinetic drug interactions between fenebrutinib and MTX. Eighteen healthy male subjects were enrolled in the study. They received a single oral dose of MTX (7.5 mg) on day 1 followed by a 13-day washout period. Subsequently, on days 15-20 the participants received 200 mg of fenebrutinib twice daily. On day 21, they received a 7.5 mg dose of MTX and a 200 mg dose of fenebrutinib under fasting conditions. The geometric mean ratios of MTX area under the plasma concentration-time curve (AUC) and C _max on day 21 relative to day 1 (90% confidence interval [CI]) were 0.96 (0.88-1.04) and 1.05 (0.94-1.18), respectively. The geometric mean ratios of fenebrutinib AUC and C _max for day 21 relative to day 20 (90% CI) were 1.03 (0.95-1.11) and 1.02 (0.90-1.15), respectively. The combination treatment was well tolerated, with an adverse event profile similar to that reported in other MTX trials. These results indicate that there is no clinically significant pharmacokinetic interaction between fenebrutinib and MTX.

Side effects of methotrexate therapy for rheumatoid arthritis: A systematic review

Methotrexate (MTX) is used as an anchor disease-modifying anti-rheumatic drugs (DMARDs) in treating rheumatoid arthritis (RA) because of its potent efficacy and tolerability. MTX benefits a large number of RA patients but partially suffered from side effects. A variety of side effects can be associated with MTX when treating RA patients, from mild to severe or discontinuation of the treatment. In this report, we reviewed the possible side effects that MTX might cause from the most common gastrointestinal toxicity effects to less frequent malignant diseases. In order to achieve regimen with less side effects, the administration of MTX with appropriate dose and a careful pretreatment inspection is necessary. Further investigations are required when combining MTX with other drugs so as to enhance the efficacy and reduce side effects at the same time. The management of MTX treatment is also discussed to provide strategies for occurred side effects. Thus, this review will provide scholars with a comprehensive understanding the side effects of MTX administration by RA patients.

Methotrexate-induced pancytopenia: a case series of 46 patients

AIM

Methotrexate (MTX) has the potential to cause serious adverse reactions and even mortality. We analyzed the predisposing factors and outcome in patients with MTX-induced pancytopenia admitted into our unit from 1996 to 2015.

METHODS

Patients were identified by departmental database search. Pancytopenia was defined as white blood cell count (WBC) < 3500 cells/mm³ , hemoglobin (Hb) < 11 g/dL and platelet count < 150 000 cells/mm³ . Severe pancytopenia was defined as WBC < 2000 cells/mm³ , Hb < 10 g/dL and platelet count < 50 000 cells/mm³ .

RESULTS

Forty-six patients were included in the study (female = 35). Twenty-four had been under the care of either primary care physicians or orthopedic surgeons and presented to us with pancytopenia. Sixteen patients had severe pancytopenia. Disease distribution was as follows: rheumatoid arthritis 33, psoriasis eight, systemic sclerosis two and others three. The median dose of MTX was 10 mg/week and median duration of treatment was 11 months. The median cumulative dose was 750 mg. Symptoms at presentation included: oral mucositis (n = 37); fever (n = 24); diarrhea (n = 12), bleeding gums (n = 5) and purpura (n = 3). The potential risk factors were: hypoalbuminemia (n = 23), renal insufficiency (n = 14), dosing errors (n = 13) and non-supplementation of folates (n = 7). Thirteen patients died. WBC at admission was found to determine survival (P < 0.05).

CONCLUSION

In patients on MTX, oral mucositis and fever can herald pancytopenia. MTX-induced pancytopenia is associated with high mortality. WBC at admission is the most important prognostic factor. There is need for increased awareness among physicians to minimize prescribing errors. A national guideline on monitoring of patients on MTX is desirable.

Methotrexate efficacy and tolerability after switching from oral to subcutaneous route of administration in juvenile idiopathic arthritis

Objectives

Methotrexate (MTX) is one of the most frequently used, highly effective disease-modifying drugs in juvenile idiopathic arthritis (JIA) therapy. The drug can be administered orally or subcutaneously, but the efficacy and tolerance of these two routes of administration raise doubts in JIA patients. The aim of the study was to evaluate MTX efficacy and tolerability after switching from the oral to the subcutaneous route of administration in children with JIA.

Material and methods

A single-centre, questionnaire-based assessment of MTX efficacy and tolerance in 126 unselected JIA patients with longer than 6 months of follow-up was performed. In all patients, MTX was initially administered orally. The response to MTX treatment was analysed according to American College of Rheumatology (ACR) paediatric criteria.

Results

Six-month MTX therapy was effective (ACR score ≥ 30) in 83 children (65.9%). The oral route of MTX administration was changed to subcutaneous in 32 patients after a mean period of 14 months due to intolerance (n = 20) or reluctance to take the oral formulation (n = 12). This group of children was significantly younger (p = 0.02) but did not differ from the group of children that continued oral treatment in other aspects, including MTX dose.

Six months after switching from oral to subcutaneous MTX the ACR score remained unchanged. Three children (9.4%) still reported symptoms of drug intolerance.

Conclusions

The switch from oral to subcutaneous MTX may increase the response rate in JIA patients with intolerance of its oral formulation. The reluctance to take oral MTX can be anticipated in early childhood, and should be considered in the individualization of therapy, having also in mind the lower risk of severe gastrointestinal adverse drug reactions.

Methotrexate for the treatment of thyroid eye disease

Background/Aim. To evaluate the efficacy of methotrexate for the treatment of thyroid eye disease (TED). Methods. 36 consecutive patients with active TED, previously treated with corticosteroids but stopped due to the occurrence of side effects, were commenced on methotrexate therapy. Two different weekly doses were administered depending on the weight of the patient (7.5 mg or 10 mg). Clinical activity score (7-CAS), visual acuity (VA), ocular motility, exophthalmos, and eyelid position were retrospectively evaluated at 3, 6, and 12 months and compared with baseline data. Results. There was a statistically significant improvement in 7-CAS at 3, 6, and 12 months after treatment (P < 0.0001). There was no significant change in visual acuity. Ocular motility disturbances improved at 6 and 12 months (P < 0.001). There was no significant change in exophthalmos (mean 24 mm, SD 3 mm) or eyelid position (marginal reflex distance mean 6 mm, SD 1.5 mm) during the follow-up period. No side effects were registered. Conclusions. Methotrexate therapy is effective in reducing CAS and ocular motility disturbances. No significant improvement in proptosis or eyelid retraction should be expected from this treatment. Eventually, it might be considered a suitable alternative treatment in TED for patients who cannot tolerate steroids.

Intra-articular methotrexate in the treatment of rheumatoid arthritis and psoriatic arthritis: a clinical and sonographic study

The aim of our study was to evaluate the effects of intra-articular methotrexate (MTX) in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Twenty-three consecutive patients, 10 with RA and 13 with PsA, with prevalent or unique arthritic involvement of one knee, were treated with intra-articular injections of MTX 10 mg every 7 days for 8 weeks. Before the beginning of the treatment and after 9 and 17 weeks, the patients underwent a clinical evaluation measuring maximal knee flexion angle, visual analog scale (VAS) and erythrocyte sedimentation rate (ESR). On the same days, an ultrasonographic examination of the involved knee was performed by two independent experienced operators. Synovial thickness in the suprapatellar bursa and the presence of joint effusion and Baker's cyst were assessed. An increase of the mean value of maximal knee flexion angle and a reduction of the mean values of ESR and VAS between T0, T9 and T17 were demonstrated. Ultrasonographic evaluation showed significant reduction of synovial thickness and joint effusion. No differences were detected for the presence of Baker's cyst. We may conclude that repeated intra-articular injections of MTX resulted in a decrease of local as well as systemic inflammatory signs. As far as we know, this is the first study that explores the effects of intra-articular MTX in RA and PsA both clinically and by ultrasonography.

Noise-induced autoimmune sensorineural hearing loss

Typically, autoimmune sensorineural hearing loss has been described as a slowly progressive, asymmetric hearing loss that is responsive to medications traditionally used in the treatment of other autoimmune conditions. These medications include steroids and cytotoxic drugs. Inciting factors in autoimmune inner ear disease are rarely cited. We describe a case of episodic sudden hearing loss triggered consistently by environmental noise. The hearing loss was responsive to steroids at the time of each occurrence and was determined to be autoimmune. This case raises questions about the relationship between autoimmune inner ear disease and sensitivity to environmental noise that warrant further research.

Pharmacokinetics and pharmacodynamics of methotrexate in non-neoplastic diseases

Low dose pulse methotrexate (LDMTX) therapy has become effective in the treatment of autoimmune and lymphoproliferative diseases. The pharmacokinetics of LDMTX is individually highly variable, resulting in a different systemic exposure to the drug and a variable therapeutic/toxic effect in patients. The improvements and exacerbations of disease activity in relation to the introductions and discontinuations of LDMTX therapy suggest the possible immunosuppresive and anti-inflammatory properties of the drug. Because of a strong correlation between the drug pharmacokinetics and the therapeutic outcomes (pharmacodynamics), it seems to be possible to individualise the LDMTX therapy according to the results of pharmacokinetic/pharmacodynamic analysis. In the case of psoriasis, pharmacokinetic/pharmacodynamic analysis in our local study revealed a highly significant inverse relationship between PASI (expressed as a percent of the initial value) and a steady-state AUC(MTX) (area under the curve of methotrexate plasma concentrations; r(8) = -0.65, p < 0.001). The considerable inter-individual variability and low intra-individual variability in MTX pharmacokinetics, supports a role for therapeutic monitoring and dose individualisation at the start of pharmacotherapy. The results of this study suggest that a steady-state AUC(MTX) value of 700 nmol x h/L and higher are associated with a significantly better success rate of antipsoriatic therapy than lower values. The preliminary results in our follow-up study suggest the statistically higher incidence of unwanted effects depending on maximum plasma concentration of the drug. Moreover, statistically significant correlation was found between the toxic effects and exposure to the drug regarding methotrexate plasma concentrations and intracellular storage in erythrocytes. However, the data are still in the process of being completed and are not yet published.

Pharmacokinetics and pharmacodynamics of low-dose methotrexate in the treatment of psoriasis

AIMS

The aim of this 13 week, randomized, parallel-group study was to evaluate the relationship between the pharmacokinetics (PK) and pharmacodynamics (PD) of low-dose intermittent oral methotrexate (LDMTX) in patients with psoriasis.

METHODS

Twenty-four psoriatic patients (15 male and 9 female, aged 31-73 years) were given weekly doses of MTX doses of either 7.5 mg or 15 mg with each dose divided into three aliquots given at 12 h intervals. The pharmacokinetics of MTX were evaluated at weeks 1 and 13. Skin impairment was assessed using the PASI-scoring system (The Psoriasis Area and Severity Index) at baseline and at weeks 5, 9 and 13 of therapy. Haematological and biochemistry tests were also performed at these times.

RESULTS

The comparison of the areas under the plasma concentration-time curve (AUC(MTX)) after the first and third weekly doses showed that the extent of MTX accumulation in plasma was only about 12%. Two-way anova (factors: subject and the week of therapy) on the log-transformed AUC(MTX) showed no effect of the week of therapy (P>0.8). Moreover, the intraindividual variability in the AUC(MTX) was at least 4-fold less than the interindividual variability (F-test; P<0.01). The steady-state total plasma clearance of MTX ranged from 5.0 to 18.2 l h(-1) and was proportional to the renal clearance (r2=0.45, P<0.001) which accounted for 65+/-20% of the former. The renal clearance of 7-OHMTX was approximately 4-8% of that of the parent compound. PK/PD analysis revealed a highly significant inverse relationship between PASI (expressed as a percent of the initial value) and a steady-state AUC(MTX) (rs=-0.65, P<0.001). Seventeen subjects (8 from the 7.5 mg group and 9 from the 15 mg group MTX, P=0.67) achieved a greater than 50% decrease in the initial PASI score and were classified as responders. Thirteen of 14 subjects with AUC(24,36 h)> or =700 nmol l(-1) h responded to pharmacotherapy. Conversely, only 4 out of 10 subjects with AUC(24,36 h)<700 nmol l-1 h were responders (P<0.01, Fisher's exact test).

CONCLUSIONS

A strong correlation was observed between the pharmacokinetics (AUC(MTX) at the steady state) and antipsoriatic effect (PASI-score) of LDMTX. The considerable interindividual variability and low intraindividual variability in MTX pharmacokinetics support a role for therapeutic monitoring and dose individualization at the start of pharmacotherapy. The results of this study suggest that a steady state AUC(MTX) values of 700 nmol l(-1)h and higher are associated with a significantly better success rate of antipsoriatic therapy than lower values.

Lack of pharmacokinetic interaction between rofecoxib and methotrexate in rheumatoid arthritis patients

Rofecoxib is a highly selective and potent inhibitor of cyclooxgenase-2 (COX-2). Methotrexate is a disease-modifying agent with a narrow therapeutic index frequently prescribed for the management of rheumatoid arthritis. The objective of this study was to investigate the influence of clinical doses of rofecoxib on the pharmacokinetics of methotrexate in patients with rheumatoid arthritis. This was a randomized, double-blind, placebo-controlled study in 25 rheumatoid arthritis patients on stable doses of methotrexate. Patients received oral methotrexate (7.5 to 20 mg) on days -1, 7, 14, and 21. Nineteen patients received rofecoxib 12.5, 25, and 50 mg once daily on days 1 to 7, 8 to 14, and 15 to 21, respectively. Six patients received placebo on days 1 to 21 only to maintain a double-blinded design for assessment of adverse experiences. Plasma and urine samples were analyzed for methotrexate and its major although inactive metabolite, 7-hydroxymethotrexate. The AUC(0-infinity) geometric mean ratios (GMR) and their 90% confidence intervals (90% CI) (rofecoxib + methotrexate/methotrexate alone) for day 7/day -1, day 14/day -1, and day 21/day -1, for rofecoxib 12.5, 25, and 50 mg, were 1.03 (0.93, 1.14), 1.02 (0.92, 1.12), and 1.06 (0.96, 1.17), respectively (p > 0.2 for all comparisons to day -1). All AUC(0-infinity), GMR and Cmax GMR 90% CIs fell within the predefined comparability limits of (0.80, 1.25). Similar results were observed for renal clearance of methotrexate and 7-hydroxymethotrexate at the highest dose of rofecoxib tested (50 mg). It was concluded that rofecoxib at doses of 12.5, 25, and 50 mg once daily has no effect on the plasma concentrations or renal clearance (tested at the highest dose of rofecoxib) of methotrexate in rheumatoid arthritis patients.

Prospidine versus methotrexate pulse in highly active rheumatoid arthritis: a controlled 6-month clinical trial

Twenty-seven patients with highly active, refractory rheumatoid arthritis (RA) were treated with the new anti-rheumatic drug prospidine, in view of selecting the optimum pulse regimen and comparing its short-term use with methotrexate (MTX). Prospidine was administered intravenously 500 mg every 3-5 days in the hospital and then monthly. Fifteen patients received MTX (30 mg/week intravenously in hospital and then monthly. Fifteen patients received MTX (30 mg/week intravenously in hospital and then orally 7.5-15 mg/week). The randomisation code was 2:1. We assessed 7 clinical and 4 lab data. The clinical improvement was noticed statistically after 2-4 weeks in 85% prospidine-patients and sustained up to 6 months in 73% (cp. 40% and 57% by the MTX). Only in the prospidine patients were a significant reduction of the mean daily prednisolone dose and the levels of rheumatoid factor and immune complexes observed. Prospidine and MTX had a similar incidence of side effects (39% and 43%), but all drop-outs in prospidine pulse were due to lack of response (26%) and to initial intolerance (4%). Drop-outs in MTX pulse were connected both with drug toxicity (14%) and with lack of response (7%). Alternate prospidine pulse, as highly anti-inflammatory, rapidly acting and well-tolerated regimen, may be used in treating severe forms of RA.

Methotrexate in rheumatoid arthritis. An update

Methotrexate has been approved for the treatment of refractory rheumatoid arthritis by several regulatory agencies, including the Food and Drug Administration. The tendency is now to prescribe it at earlier stages of the disease. Methotrexate is a well known antifolate. Its exact mechanism of action in rheumatoid arthritis remains uncertain. The polyglutamated derivatives of methotrexate are potent inhibitors of various enzymes, including dihydrofolate reductase and 5-aminoimidazole-4-carboxamide ribonucleotide transformylase. Inhibitory effects on cytokines, particularly interleukin-1, and on arachidonic acid metabolism, as well as effects on proteolytic enzymes, have been reported. Some of them may be linked to the antifolate properties of methotrexate. Overall, the drug appears to act in rheumatoid arthritis as an anti-inflammatory agent with subtle immunomodulating properties. Direct inhibitory effects on rapidly proliferating cells in the synovium have also been suggested. Methotrexate is usually given orally. Marked interindividual variation in its bioavailability has been found. Food intake has no significant effect on the pharmacokinetics of oral methotrexate. Methotrexate undergoes significant metabolism. The functionally important metabolites are the polyglutamated derivatives of methotrexate, which are selectively retained in the cells. Less than 10% of a dose of methotrexate is oxidised to 7-hydroxy-methotrexate, irrespective of the route of administration. This metabolite is extensively (91 to 93%) bound to plasma proteins, in contrast to the parent drug (35 to 50% bound). Methotrexate is mainly excreted by the kidneys. It undergoes tubular secretion and may thereby compete with various organic acid compounds. Early placebo-controlled trials demonstrated that weekly low dosage methotrexate produced early symptomatic improvement in most rheumatoid arthritis patients. Two meta-analyses showed that methotrexate is among the most efficacious of slow-acting antirheumatic agents, together with parenteral gold (sodium aurothiomalate), penicillamine and sulfasalazine. Furthermore, in the short term context of clinical trials, methotrexate has one of the best efficacy/toxicity ratios. There is little evidence that methotrexate, or any available slow-acting antirheumatic agent, is a true disease-modifying drug. However, the probability that a patient will continue methotrexate therapy over time appears quite favourable compared with any other slow-acting antirheumatic drug. Combination therapy with slow-acting drugs has been advised for the management of rheumatoid arthritis, but the evidence currently available does not support general use of combination therapy including methotrexate. Almost all investigations indicated that toxic effects, rather than lack of response, were the major reason for discontinuing methotrexate therapy.(ABSTRACT TRUNCATED AT 400 WORDS)