Methotrexate in Crohn's disease: a new face for an old drug?

Saudi consensus guidance for the diagnosis and management of inflammatory bowel disease in children and adolescents

ABSTRACT

The management of inflammatory bowel disease (IBD) in children and adolescents is challenging. Clear evidence-based guidelines are required for this population. This article provides recommendations for managing IBD in Saudi children and adolescents aged 6-19 years, developed by the Saudi Ministry of Health in collaboration with the Saudi Society of Clinical Pharmacy and the Saudi Gastroenterology Association. All 57 guideline statements are based on the most up-to-date information for the diagnosis and management of pediatric IBD.

Therapeutic drug monitoring of methotrexate in patients with Crohn's disease

BACKGROUND

Therapeutic drug monitoring (TDM) has the potential to improve efficacy and diminish side effects. Measuring methotrexate-polyglutamate (MTX-PG) in erythrocytes might enable TDM for methotrexate in patients with Crohn's disease (CD).

AIM

To investigate the relationship between MTX-PGs and methotrexate drug survival, efficacy and toxicity METHODS: In a multicentre prospective cohort study, patients with CD starting subcutaneous methotrexate without biologics were included and followed for 12 months. Primary outcome was subcutaneous methotrexate discontinuation or requirement for step-up therapy. Secondary outcomes included faecal calprotectin (FCP), Harvey Bradshaw Index (HBI), hepatotoxicity and gastrointestinal intolerance. Erythrocyte MTX-PGs were analysed at weeks 8, 12, 24 and 52 or upon treatment discontinuation.

RESULTS

We included 80 patients with CD (mean age 55 ± 13y, 35% male) with a median FCP of 268 μg/g (IQR 73-480). After the 12-month visit, 21 patients (26%) were still on subcutaneous methotrexate monotherapy. Twenty-one patients stopped because of disease activity, 29 because of toxicity, and four for both reasons. Five patients ended study participation or stopped methotrexate for another reason. A higher MTX-PG3 concentration was associated with a higher rate of methotrexate drug survival (HR 0.86, 95% CI 0.75-0.99), lower FCP (β -3.7, SE 1.3, p < 0.01) and with biochemical response (FCP ≤250 if baseline >250 μg/g; OR 1.1, 95% CI 1.0-1.3). Higher MTX-PGs were associated with less gastrointestinal intolerance. There was no robust association between MTX-PGs and HBI or hepatotoxicity.

CONCLUSIONS

Higher MTX-PG3 concentrations are related to better methotrexate drug survival and decreased FCP levels. Therefore, MTX-PG3 could be used for TDM if a target concentration can be established.

Cost-Effectiveness Analysis of Parenteral Methotrexate for the Treatment of Crohn's Disease

BACKGROUND

Despite worldwide use of parenteral methotrexate (pMTX), health economic evidence for its use in Crohn's disease (CD) is limited. The low price of this generic drug has removed any commercial incentive to further invest in research. However, there is an unmet need for treatment of mild-to-moderate CD, since biological/targeted therapies are usually reserved for patients with more severe disease due to the higher costs of these treatments.

OBJECTIVE

To evaluate the cost-effectiveness of pMTX compared to the standard of care (SOC, i.e., high doses of oral corticosteroids (hdCS) followed by gradual tapering) for the treatment of mild-to-moderate CD in the Czech Republic.

METHODS

We developed a 3-year Markov model with a 1-week cycle length comprising five health states. The model projected quality-adjusted life-years (QALYs) and costs from the healthcare payers' perspective. Efficacy data were obtained from a systematic literature review of clinical trials and extrapolated using survival analysis.

RESULTS

Over a 3-year time-horizon, pMTX yields additional 0.111 QALYs (1.798 vs. 1.687) at an additional cost of €513 (€3087 vs. €2574), with an incremental deterministic (probabilistic) cost-effectiveness ratio of €4627 (€4742)/QALY, far below the willingness-to-pay (WTP) threshold (≈ €47,000/QALY). The probabilistic sensitivity analysis showed that the probability of pMTX being cost-effective was 100%. A one-way sensitivity and scenario analysis confirmed the robustness of the base-case result.

CONCLUSION

Parenteral MTX proved to be cost-effective in patients with mild-to-moderate CD. This is the first published cost-effectiveness analysis of pMTX for this indication. It also shows an example of a lack of valuation of generic therapy despite its cost-effectiveness and a clear benefit to the healthcare system.

Current, experimental, and future treatments in inflammatory bowel disease: a clinical review

Inflammatory bowel diseases (IBDs) may result from dysregulated mucosal immune responses directed toward the resident intestinal microbiota. This review describes the hallmark immunobiology of Crohn's disease and ulcerative colitis as well as therapeutic targets and mechanisms of action for current, experimental, and future treatments in IBD. Conventional therapies include 5-aminosalicylic acid, glucocorticosteroids, thiopurines, and methotrexate. Since 1997, monoclonal antibodies have gained widespread use. These consist of antibodies directed against pro-inflammatory cytokines such as tumor necrosis factor α, interleukin (IL)-12, and IL-23, or anti-homing antibodies directed against α4β7 integrin. Emerging oral therapies include modulators of intracellular signal transduction such as Janus kinase inhibitors. Vitamin D may help to regulate innate and adaptive immune responses. Modulation of the intestinal microbiota, using live microorganisms (probiotics), substrates for the colonic microbiota (prebiotics), or fecal microbiota transplantation (FMT), is in development. Dietary supplements are in widespread use, but providing evidence for their benefit is challenging. Stem cell treatment and nervous stimulation are promising future treatments.

Serine Is an Essential Metabolite for Effector T Cell Expansion

During immune challenge, T lymphocytes engage pathways of anabolic metabolism to support clonal expansion and the development of effector functions. Here we report a critical role for the non-essential amino acid serine in effector T cell responses. Upon activation, T cells upregulate enzymes of the serine, glycine, one-carbon (SGOC) metabolic network, and rapidly increase processing of serine into one-carbon metabolism. We show that extracellular serine is required for optimal T cell expansion even in glucose concentrations sufficient to support T cell activation, bioenergetics, and effector function. Restricting dietary serine impairs pathogen-driven expansion of T cells in vivo, without affecting overall immune cell homeostasis. Mechanistically, serine supplies glycine and one-carbon units for de novo nucleotide biosynthesis in proliferating T cells, and one-carbon units from formate can rescue T cells from serine deprivation. Our data implicate serine as a key immunometabolite that directly modulates adaptive immunity by controlling T cell proliferative capacity.