Differing contribution of methotrexate polyglutamates to adalimumab blood levels as compared with etanercept

Methotrexate polyglutamates

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. Eligible studies included reviews, clinical trials, and real-world analyses. Additional manual searches and citation reviews were also performed. This review aims to explore MTXPGs with a primary focus on their pharmacokinetics, analytical methods, determinants of drug exposure, and their correlation with MTX efficacy and toxicity.

EXPERT OPINION

MTXPGs have not yet garnered significant attention in clinical practice. However, multiple studies have demonstrated a relationship between MTXPGs and the efficacy and toxicity of MTX, suggesting a potential avenue for personalized treatment strategies. Future research should aim to further validate and refine this correlation. Additionally, attention should also be directed toward other metabolites of MTX, which may hold clinical significance.

Efficacy of Combined Initial Treatment of Methotrexate with Infliximab in Pediatric Crohn's Disease: A Pilot Study

BACKGROUND

The combination of antitumor necrosis factor-alpha (TNF-α) agents with immunomodulators (IMMs) is a common treatment for pediatric Crohn's disease (CD). Although methotrexate (MTX) can be a first-line medication as an IMM, most clinicians in real-life practice, especially in South Korea, are more familiar with thiopurines. This study aimed to compare the efficacy and immunogenicity of MTX and azathioprine (AZA) as concurrent therapies for pediatric CD.

METHODS

In this pilot study, 29 newly diagnosed pediatric patients with moderate-to-severe CD were randomized to receive either MTX (n = 15) (15 mg/body surface area (BSA) per week) or oral AZA (n = 14) (0.5 mg/kg per day) in combination with Infliximab (IFX). The primary outcomes were the proportion of patients in endoscopic, biochemical, and transmural remission after 14 and 54 weeks of IFX therapy. The trough levels (TLs) of IFX and anti-drug antibody (ADA) levels were also compared.

RESULTS

Among the 29 patients, there were no significant differences in the biochemical (p = 1.0 at week 14, p = 0.45 at week 54), endoscopic (p = 0.968 at week 14, p = 0.05 at week 54), or transmural (p = 0.103 at week 54) remission rates between the two medications during the concurrent therapy. Additionally, the trends in the IFX trough and ADA levels over time during the treatments were similar for both medications, with no significant differences (p = 0.686, p = 0.389, respectively).

CONCLUSION

The MTX showed comparable efficacy to the AZA in pediatric CD patients with moderate-to-severe disease. This effectively maintained adequate IFX levels and reduced ADA production. Therefore, although additional large-scale clinical trials are needed, this study demonstrated that either MTX or AZA can be selected as IMMs in the concurrent treatment of pediatric CD, depending on individual medical institutions' circumstances.

Combining nanotechnology with monoclonal antibody drugs for rheumatoid arthritis treatments

Rheumatoid arthritis (RA) is a systemic immune disease characterized by synovial inflammation. Patients with RA commonly experience significant damage to their hand and foot joints, which can lead to joint deformities and even disability. Traditional treatments have several clinical drawbacks, including unclear pharmacological mechanisms and serious side effects. However, the emergence of antibody drugs offers a promising approach to overcome these limitations by specifically targeting interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and other cytokines that are closely related to the onset of RA. This approach reduces the incidence of adverse effects and contributes to significant therapeutic outcomes. Furthermore, combining these antibody drugs with drug delivery nanosystems (DDSs) can improve their tissue accumulation and bioavailability.Herein, we provide a summary of the pathogenesis of RA, the available antibody drugs and DDSs that improve the efficacy of these drugs. However, several challenges need to be addressed in their clinical applications, including patient compliance, stability, immunogenicity, immunosupression, target and synergistic effects. We propose strategies to overcome these limitations. In summary, we are optimistic about the prospects of treating RA with antibody drugs, given their specific targeting mechanisms and the potential benefits of combining them with DDSs.

Immunogenicity of biologic agents in rheumatology

Biologic agents have become a core component of therapeutic strategies for many inflammatory rheumatic diseases. However, perhaps reflecting the specificity and generally high affinity of biologic agents, these therapeutics have been used by rheumatologists with less consideration of their pharmacokinetics than that of conventional synthetic DMARDs. Immunogenicity was recognized as a potential limitation to the use of biologic agents at an early stage in their development, although regulatory guidance was relatively limited and assays to measure immunogenicity were less sophisticated than today. The advent of biosimilars has sparked a renewed interest in immunogenicity that has resulted in the development of increasingly sensitive assays, an enhanced appreciation of the pharmacokinetic consequences of immunogenicity and the development of comprehensive and specific guidance from regulatory authorities. As a result, rheumatologists have a greatly improved understanding of the field in general, including the factors responsible for immunogenicity, its potential clinical consequences and the implications for everyday treatment. In some specialties, immunogenicity testing is becoming a part of routine clinical management, but definitive evidence of its cost-effectiveness in rheumatology is awaited.