The methotrexate polyglutamate assay supports the efficacy of methotrexate for severe inflammatory skin disease in children

How can we optimize the use of methotrexate to treat pediatric patients with inflammatory skin diseases?

INTRODUCTION

Methotrexate (MTX) is a folic acid antagonist used in clinical practice in oncology and rheumatology, as well as in the treatment of inflammatory skin conditions in children. The low-doses of MTX are commonly used in children for the treatment of many inflammatory and autoimmune conditions, including inflammatory skin diseases, due to its anti-inflammatory and immunomodulatory effects.

AREAS COVERED

This review discusses the possibilities for optimizing the use of methotrexate in the treatment of pediatric patients with inflammatory skin diseases. A thorough search through PubMed and Embase databases was performed to identify relevant literature.

EXPERT OPINION

Clinical observations confirm the high efficacy and safety of low-dose MTX in children with inflammatory skin diseases. Unfortunately, to date there are few studies providing guidelines on the optimal dosage of MTX in children with inflammatory skin diseases; routes of administration; principles of monitoring; and the safety of long-term use of this medication in children. There is still a need for specific recommendations on the safest and most effective dosing and monitoring regimen for children treated with methotrexate for inflammatory skin diseases.

Oral Versus Subcutaneous Methotrexate in Immune-Mediated Inflammatory Disorders: an Update of the Current Literature

PURPOSE

This review aims to critically evaluate the potential benefit of either oral or subcutaneous administration of methotrexate (MTX) in various immune-mediated inflammatory disorders (IMIDs) through analysis of efficacy, toxicity, pharmacokinetics and pharmacodynamics of both administration routes.

RECENT FINDINGS

Recent studies comparing the efficacy of oral versus subcutaneous MTX administration in IMIDs have revealed contradicting results. Some reported higher efficacy with subcutaneous administration, while others found no significant difference. Regarding toxicity, some studies have challenged the notion that subcutaneous administration is better tolerated than oral administration, while others have supported this. Pharmacokinetic studies suggest higher plasma bioavailability and increased accumulation of MTX-polyglutamates (MTX-PGs) in red blood cells (RBCs) with subcutaneous administration during the initial treatment phase. However, after several months, similar intracellular drug levels are observed with both administration routes. There is no conclusive evidence supporting the superiority of either oral or subcutaneous MTX administration in terms of efficacy and adverse events in IMIDs. Subcutaneous administration leads to higher plasma bioavailability and initial accumulation of MTX-PGs in RBCs, but the difference seems to disappear over time. Given the variable findings, the choice of administration route may be based on shared decision-making, offering patients the option of either oral or subcutaneous administration of MTX based on individual preferences and tolerability. Further research is needed to better understand the impact of MTX-PGs in various blood cells and TDM on treatment response and adherence to MTX therapy.

A meta-analysis of methotrexate polyglutamates in relation to efficacy and toxicity of methotrexate in inflammatory arthritis, colitis and dermatitis

AIMS

In immune-mediated inflammatory diseases (IMIDs), early symptom control is a key therapeutic goal. Methotrexate (MTX) is the first-line treatment across IMIDs. However, MTX is underutilized and suboptimally dosed, partly due to the inability of making individualized treatment decisions through therapeutic drug monitoring (TDM). To implement TDM in clinical practice, establishing a relationship between drug concentration and disease activity is paramount. In this meta-analysis, we investigated the relationship between concentrations of MTX polyglutamates (MTX-PG) in erythrocytes and efficacy as well as toxicity across IMIDs.

METHODS

Studies analysing MTX-PG in relation to disease activity and/or toxicity were included for inflammatory arthritis (rheumatoid [RA] and juvenile idiopathic arthritis [JIA]), inflammatory bowel disease (Crohn's and ulcerative colitis) and dermatitis (psoriasis and atopic dermatitis). Meta-analyses were performed resulting in several summary effect measures: regression coefficient (β), correlation coefficient and mean difference (of MTX-PG in responders vs. nonresponders) for IMIDs separately and collectively.

RESULTS

Twenty-five studies were included. In RA and JIA, higher MTX-PG was significantly associated with lower disease activity at 3 months (β: -0.002; 95% confidence interval [CI]: -0.004 to -0.001) and after 4 months of MTX use (β: -0.003; 95% CI: -0.005 to -0.002). Similarly, higher MTX-PG correlated with lower disease activity in psoriasis (R: -0.82; 95% CI: -0.976 to -0.102). Higher MTX-PG was observed in RA, JIA and psoriasis responders (mean difference: 5.2 nmol/L MTX-PG_total ; P < .01).

CONCLUSION

We showed that higher concentrations of erythrocyte MTX-PG were associated with lower disease activity in RA, JIA and psoriasis. These findings are an important step towards implementation of TDM for MTX treatment across IMIDs.

On which evidence can we rely when prescribing off-label methotrexate in dermatological practice? - a systematic review with GRADE approach

If an authorized drug is prescribed for a use that is not described in the Summary of Product Characteristics, this is defined as 'off-label use.' Methotrexate is often used off-label for dermatological indications. Off-label use is permitted if physicians can justify the treatment based on scientific evidence available to them. Our objective here was therefore to summarize the evidence for the effectiveness, efficacy, and safety of the dermatological off-label use of methotrexate in a systematic review. We searched MEDLINE, EMBASE, and CENTRAL for studies for evidence on the effectiveness, efficacy, and safety of the off-label use of methotrexate in dermatological indications up to November 2019. We used the GRADE system to rate the quality of the evidence. The search retrieved 34,583 hits of which 3566 were selected after the title and abstract screening. After the full-text screening, 143 studies were included, which involved 3688 patients in total. We found low-quality evidence for the effectiveness, efficacy, and safety of the off-label use of methotrexate in 31 dermatological diseases. To optimize the quality of evidence to support off-label use, we need high-quality studies in which well-characterized patients are treated with standardized treatments regimens using well-validated outcomes relevant to patients and physicians.

Methotrexate Polyglutamates Analysis by Chromatography Methods in Biological Matrices: A Review

Methotrexate (MTX) is used as an immunosuppressant and antineoplastic drug in clinical practice. MTX is a parent drug and converts to MTX polyglutamates (MTXPGs) to exhibit its biological activity. Clinical studies found that MTXPG levels were associated with MTX response and toxicities, especially at low doses. Due to huge variance of MTX response and toxicities between individuals, therapeutic drug monitoring is necessary for its use in individualized therapy. Various chromatography methods coupled with ultraviolet-visible detector, fluorescence detector and mass spectrometry have been reported for MTXPG analysis in various biological matrices. The aim of this paper is to review the chromatographic based methods for the measurement of total and/or individual MTXPGs. We searched Embase, Science Direct and PubMed databases using "methotrexate polyglutamate" and "chromatography" as search terms, and found 745 articles. Of those, 14 articles were extracted for this study. The key steps for method development (sample pretreatment, parameter optimization of liquid chromatography and mass spectrometry, selection of internal standard) and validation (lower limit of quantitation, accuracy, precision, recovery, matrix effect and stability) were analyzed and summarized, which might be helpful for researchers to develop their own methods.

Transition of Methotrexate Polyglutamate Drug Monitoring Assay from Venipuncture to Capillary Blood-Based Collection Method in Rheumatic Diseases

Objective

Methotrexate (MTX) polyglutamate (MTXPG3) levels from isolated red blood cells (RBCs) collected by venipuncture have clinical utility in guiding MTX dosing for patients with rheumatoid arthritis (RA). Our objective was to transition this RBC-based therapeutic drug monitoring (TDM) assay to dried capillary blood collected by fingerstick.

Methods

Patients with RA treated with MTX were enrolled. Specimens were collected by fingerstick (volumetric absorptive microsampler) and venipuncture to measure MTXPG3 from dried capillary blood, total venous blood, and isolated RBCs. MTXPG3 levels from dried capillary blood were measured using LC-MS/MS, converted to RBC equivalent (nmol/L), and compared with those from isolated RBCs (reference method). Following transition to fingerstick collection, comparability in the distributions of dried capillary and venipuncture-based RBC MTXPG3 levels was assessed using the Kolmogorov–Smirnov (K-S) test.

Results

Intraday and interday precision ranged from 2.0% to 10.9% and 3.1% to 10.8%, respectively, at MTXPG3 concentrations ranging from 5 to 100 nmol/L. In 106 participants treated with MTX, MTXPG3 levels from total venous and dried capillary blood were comparable [slope = 0.97 (95% CI, 0.92–1.03); R2 = 0.92]. Dried capillary blood MTXPG3 converted to RBC equivalent was similar to levels from isolated RBCs (30 ± 18 nmol/L vs 33 ± 19 nmol/L; n = 106). After implementation in the clinical laboratory, RBC equivalents MTXPG3 from the fingerstick method were similar to levels from venipuncture [39 ± 22 nmol/L (n = 825) vs 39 ± 24 nmol/L (n = 47935)] (K-S test P = 0.09). Underexposure to MTX (MTXPG3 ≤5 nmol/L RBCs) was detected in 7.0% and 8.5% patient specimens collected using the fingerstick and venipuncture methods, respectively.

Conclusion

Capillary blood MTXPG3 levels can be used to guide MTX dosing in TDM practice.

Current therapeutic paradigm in pediatric atopic dermatitis: Practical guidance from a national expert panel

INTRODUCTION AND OBJECTIVES

Atopic dermatitis (AD) is the most common cutaneous inflammatory disease in both adults and children. Although emerging therapeutic approaches are being investigated for the management of pediatric AD, it still needs to be managed with conventional treatments. This consensus document is aimed at providing an update on general management and therapies of pediatric AD, defining practical recommendations for using both topical and systemic agents.

MATERIAL AND METHODS

A panel of experts consisting of dermatologists and pediatricians were convened in order to define statements, through a Delphi process, standardizing the management of AD in pediatric subjects in a real-world setting.

RESULTS

A set of practical recommendations obtaining an at least 75% agreement was presented.

CONCLUSIONS

This set of practical recommendations represents a simple and fast snapshot on the pediatric use of common anti-AD therapeutics.

An update on the topical and oral therapy options for treating pediatric atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is one of the most common childhood skin disorders. Multiple mechanisms contribute to the pathology of AD and treatment approaches are directed at these processes.

AREAS COVERED

The purpose of this review is to discuss the chemical treatment options for pediatric atopic dermatitis, including immunomodulators and small molecule inhibitors. A systematic literature search was conducted, and publications were reviewed for applicable treatment guidelines.

EXPERT OPINION

Topical therapy is first-line for pediatric atopic dermatitis. Providers should work closely with patients and caregivers to promote the success of topical treatments. In disease refractory to topical treatments, systemic agents may be considered. Clinical trials are ongoing for the use of biologics in the treatment of pediatric AD. When choosing the most appropriate treatment, physicians should consider the drug efficacy, potential adverse effects, patient adherence, and quality of life for both patients and caregivers. Additional studies are required to determine the safest and most effective doses for systemic therapy in childhood AD.

Pediatric Psoriasis

Psoriasis is a chronic inflammatory systemic disease associated with an important physical and physiological burden. It primarily affects the skin, but it is associated with several serious medical co-morbidities. One third of total psoriatic cases have their onset during the pediatric age, although some of them may not be diagnosed until the patient reaches adulthood. Additionally, in the pediatric age, there is an association with several medical co-morbidities; thus, an early recognition of the disease and a subsequent appropriate approach may delay or even prevent considerable co-morbidities. Because children are not just 'small adults', specific guidelines for the diagnosis, management, and treatment of psoriasis are of extreme importance. However, these guidelines are still lacking in this age group. Most of the psoriasis treatments used in adults are not officially approved for the pediatric age and require off-label prescription. Moreover, efficacy and safety studies are lacking in this population, especially with long-term follow-up and outcomes. Many biologic agents have been recently approved for the treatment of psoriasis in children, while others are currently being studied. This bibliographic review aims to summarize the most relevant aspects, as well as updated information about the epidemiology, pathogenesis, clinical features, diagnosis, co-morbidities and treatment of pediatric psoriasis.

Methotrexate for Severe Childhood Atopic Dermatitis: Clinical Experience in a Tertiary Center

BACKGROUND/OBJECTIVES

Atopic dermatitis (AD) affects up to 20% of children. Although the majority of patients are adequately controlled using emollients, topical corticosteroids, topical calcineurin inhibitors, or phototherapy, children with moderate to severe AD may require systemic treatment for control. The objective of the current study was to evaluate the efficacy and safety of methotrexate in children with severe AD attending a tertiary referral center.

METHODS

A retrospective chart review was undertaken of all children who received methotrexate for severe AD at our tertiary referral center from November 2010 to August 2015.

RESULTS

Forty-seven children were started on methotrexate for AD during this period. The mean Investigator Global Assessment (IGA) at the 3- to 5-month follow-up improved from 4.25 to 2.8, with further improvement to 1.9 in the patients that continued therapy beyond 10 months. Changes in the Children's Dermatology Life Quality Index (CDLQI) mirrored changes in the IGA, with improvement in the mean CDLQI from 14.4 at the start of the treatment to 7.5 at the 3- to 5-month follow-up. Further improvement in the CDLQI to 6.6 in patients who continued methotrexate beyond 10 months confirmed continued improvement in disease control beyond medium-term therapy. The treatment was well tolerated.

CONCLUSIONS

Methotrexate appears to be an effective, safe treatment for severe pediatric AD. Its therapeutic effects continue beyond the medium-term treatment period, as reflected by further improvement in IGA and CDLQI scores in patients who continued methotrexate therapy beyond 10 months.

Non-topical management of recalcitrant paediatric atopic dermatitis

Atopic dermatitis (AD) is a common chronic, pruritic skin disease in children. As the incidence of AD increases, especially in high-income countries, paediatricians may see an increasing number of recalcitrant AD cases in their practice. Although these cases are principally managed by paediatric dermatologists, it is important for paediatricians to be aware of the use and side effects of non-topical treatment like phototherapy and systemic agents as well as the evidence for alternative treatment, which caregivers may ask about. This review presents paediatric evidence for the practical use of phototherapy and certain oral immunosuppressants for paediatric AD including doses, duration of use and monitoring of adverse effects. The use of alternative therapy including traditional medicine, probiotics and the role of nutrition are also discussed. Narrow band ultraviolet B phototherapy is effective in recalcitrant paediatric AD. When phototherapy is ineffective or contraindicated, systemic drugs may be administered cautiously with close surveillance of side effects. The use of azathioprine, ciclosporin, methotrexate and mycophenolate mofetil is generally safe in the short term under close monitoring and can be effective alongside compliance to topical treatment. Alternative complementary treatment is not known to be effective. Holistic management including therapeutic patient education is important. Good quality paediatric studies for non-topical AD treatment are needed for definitive guidelines.

Psoriasis in adults and children: Kids are not just little people

Pediatric psoriasis is a common skin disorder. Although pediatric psoriasis has many similarities to adult psoriasis, there are differences in presentation, particularly in infants. In addition, a more limited therapeutic armamentarium exists for children due to different inherent risks. Nearly all therapies are unapproved in the pediatric population, with far fewer pre- and postmarketing studies having been conducted. Despite these challenges, appropriate treatment should never be denied to a young patient, as physical and psychosocial ramifications of psoriasis in the school age child and adolescent are significant. A partnership with the patient, caregivers, and primary care providers is necessary and rewarding in meeting the challenges of this chronic, incurable disease. We address the presentation, treatment options, and counseling necessary when treating psoriasis in the pediatric population.