Systematic review: Methotrexate—A poorly understood and underused medication in inflammatory bowel disease

BACKGROUND: Methotrexate, an immunosuppressant used for the treatment of inflammatory bowel disease (IBD) for over 30 years, remains underused compared to thiopurines. AIMS: To review the efficacy, safety, optimal dosing and delivery regimens of methotrexate in adults with IBD. METHODS: We conducted a systematic review of studies involving patients with IBD treated with methotrexate from inception to August 2023. All studies were included from the MEDLINE database via PubMed. RESULTS: For Crohn's disease, we included eight randomised controlled trials (RCTs) and 17 observational studies. Parenteral methotrexate effectively increased remission rates in steroid-dependent patients at 25 mg/week for 16 weeks and at 15 mg/week for maintenance. Methotrexate can be used in combination with anti-tumour necrosis factor (TNF) agents to reduce immunogenicity. Data comparing thiopurines and methotrexate remain scarce. For ulcerative colitis (UC), we included five RCTs and 10 observational studies were included; there was no evidence to support the use of methotrexate in (UC). We extracted safety data from 17 studies; mild-to-moderate adverse effects were common. The incidence of liver fibrosis or cirrhosis was low. CONCLUSION: Methotrexate is effective at inducing and maintaining remission in steroid-refractory Crohn's disease and can reduce anti-TNF-induced immunogenicity when used in combination therapy. Data regarding tolerance and safety are reassuring. These findings challenge preconceived ideas on methotrexate and suggest that it is a valid first-line conventional option for the treatment of mild-to-moderate Crohn's disease.