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Oral low-dose methotrexate improves infliximab pharmacokinetics, immunogenicity, and endoscopic outcomes in Crohn’s disease: a propensity score-adjusted real-world study

Year: 2026

Type: article

Abstract: INTRODUCTION: The effectiveness of infliximab in Crohn's disease is often compromised by immunogenicity. Oral low-dose methotrexate may offer a promising strategy to optimize infliximab therapy, yet its real-world effectiveness and safety remain uncertain. AIM: This study aimed to compare the effectiveness and safety of infliximab plus oral low-dose methotrexate versus infliximab monotherapy. METHOD: In this single-center retrospective cohort study, 119 patients with Crohn's disease received either infliximab monotherapy (n = 99) or combination therapy with oral low-dose methotrexate (10-15 mg/week; n = 20). The primary outcome was endoscopic remission (Simple Endoscopic Score for Crohn's Disease ≤ 2) at week 26. Propensity score methods, including nearest-neighbor matching and inverse probability of treatment weighting, were used to adjust for confounding. Conditional and weighted logistic regression were used to estimate treatment effects. RESULTS: After propensity score adjustment, combination therapy was associated with a significantly higher rate of endoscopic remission (aOR 3.70, 95% CI 1.16-11.75; P = 0.027). No significant differences were observed in endoscopic response or clinical outcomes. In a pharmacokinetic subgroup, combination therapy resulted in numerically higher infliximab trough concentrations and no detectable anti-drug antibodies (0% vs. 16.7%). Higher trough concentrations were associated with endoscopic remission (P = 0.033). The incidence of elevated liver enzymes was higher in the combination group (20.0% vs. 4.0%), but this difference was not statistically significant after adjustment (P = 0.058). CONCLUSION: In patients with Crohn's disease, oral low-dose methotrexate combined with infliximab was associated with significantly improved endoscopic remission at week 26 compared to infliximab monotherapy, without a statistically significant increase in adverse events.

Source: International Journal of Clinical Pharmacy

DOI: 10.1007/s11096-026-02098-z