Background: The methotrexate (MTX) polyglutamate assay has been validated in adults with arthritis.
Objective: We sought to assess clinical response rates and the value of the methotrexate polyglutamate assay in MTX-treated children with inflammatory skin diseases.
Methods: In this retrospective review, 46 MTX-treated children with a diagnosis of atopic dermatitis, psoriasis, or psoriasis-eczema overlap were serially assessed with the methotrexate polyglutamate assay.
Results: In all, 38 children (83%) achieved good to excellent response: 27 (59%) within 12 weeks and 11 (24%) after dose-adjustment. Good to excellent responses were highest for psoriasis/overlap: 15 of 16 (94%), compared with 23 of 30 (77%) with atopic dermatitis. Mean maximum polyglutamate levels were 31.5 nmol/L for responders versus 18.1 nmol/L for nonresponders (P = .035). This difference was also significant for the subset with atopic dermatitis, but not for those with psoriasis/overlap. After dose modification, late responders ultimately achieved a significantly higher mean maximum methotrexate polyglutamate assay (41.9 nmol/L) compared with nonresponders (P = .002).
Limitations: Retrospective design and small sample size were limitations.
Conclusions: MTX is an effective treatment for the majority of children with inflammatory skin diseases, but a subset requires dose modification to achieve good to excellent response. Methotrexate polyglutamate assay levels reflect response to treatment, but are most useful to support dose modification among children who fail to respond within 12 weeks.
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http://dx.doi.org/10.1016/j.jaad.2013.10.001 | DOI Listing |
Int J Mol Sci
December 2024
Department of Drug Chemistry, Pharmaceutical and Biomedical Analysis, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland.
Methotrexate (MTX) is an antifolic agent used in the first line of anti-inflammatory disease treatment and some oncologic issues. The metabolism of MTX is rapid, and the MTX concentration in the blood is not significant 24 h after administration. Unlike this, methotrexate polyglutamates (MTXPGs) can be informative biomarkers of drug exposure.
View Article and Find Full Text PDFFundam Clin Pharmacol
February 2025
CHU Saint-Étienne, Service de Rhumatologie, Mines Saint-Etienne, INSERM, SAINBIOSE U1059, Université Jean Monnet Saint-Étienne, Saint-Etienne, France.
Background: Methotrexate (MTX) is the first-line treatment for Rheumatoid Arthritis (RA), yet 30%-50% of RA patients develop resistance to MTX, which can manifest several years after treatment initiation.
Objective: This study investigates the relationship between erythrocyte methotrexate polyglutamates (MTX-PGs) subtype concentrations and clinical disease activity in RA patients undergoing long-term MTX treatment.
Methods: In this cross-sectional study, patients on a stable dose of subcutaneous MTX for several years were included.
Expert Rev Clin Pharmacol
November 2024
Department of Pharmacy, Beijing Tiantan Hospital, Capital Medical University, Beijing, P. R. China.
Introduction: Methotrexate polyglutamates (MTXPGs) are intracellular metabolites of methotrexate (MTX) that play a critical role in the drug's activity, influencing both its efficacy and toxicity. As the exact implications of MTXPGs in these processes remain a subject of debate, a comprehensive review of MTXPGs could provide valuable insights for clinicians and pharmacists, potentially minimizing adverse reactions and enhancing therapeutic outcomes.
Areas Covered: A comprehensive search of relevant literature was conducted in PubMed and Web of Science databases, including studies from their inception to April 2024.
Eur J Pharm Sci
November 2024
Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address:
Basic Clin Pharmacol Toxicol
September 2024
Department of Clinical Chemistry, Amsterdam UMC, Amsterdam, The Netherlands.
Background: Intracellular methotrexate polyglutamates (MTX-PGs) concentrations are measurable in red blood cells (RBCs) during MTX treatment. MTX-PG concentrations correlate with efficacy in patients with Crohn's disease (CD). Since RBCs are not involved in pathogenesis of CD and lack extended MTX metabolism, we determined MTX-PGs accumulation in peripheral blood mononuclear cells (PBMCs: effector cells) and intestinal mucosa (target cells) and compared those with RBCs as a potential more precise biomarker.
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