What Has Changed in the Treatment of Crohn’s Disease?

The central change in Crohn's disease management is strategic rather than merely pharmacologic. Contemporary guidelines increasingly favor early use of effective advanced therapy in patients with moderate-to-severe or high-risk disease rather than requiring failure of older “conventional” drugs first. At the same time, symptom control alone is no longer considered an adequate long-term target: clinicians are expected to monitor objective inflammation and modify treatment when active disease persists. The 2025 American College of Gastroenterology (ACG) guideline and the 2025 American Gastroenterological Association (AGA) guideline both reflect a treatment landscape transformed by multiple biologic classes and oral small molecules.

1. The old step-up sequence is no longer obligatory

A major change is the weakening of the traditional sequence in which patients had to fail corticosteroids, thiopurines or methotrexate before advanced therapy was considered. The 2025 ACG guideline suggests against requiring failure of conventional therapy before initiating advanced treatment in moderate-to-severe Crohn's disease. The rationale is that uncontrolled transmural inflammation can create irreversible bowel damage, strictures, fistulas, abscesses and surgery while clinicians wait for serial treatment failures.

This does not mean every patient with mild disease needs a biologic. It means treatment intensity should be matched to prognosis and disease burden. Extensive disease, deep ulceration, penetrating or stricturing phenotype, perianal disease, significant growth or nutritional compromise, repeated steroid requirement and early complications should all lower the threshold for an effective disease-modifying strategy.

2. Mesalamine has a smaller role

The 2025 ACG update strongly discourages oral mesalamine for induction or maintenance of luminal Crohn's disease because efficacy is limited. This is important because 5-aminosalicylates historically persisted in Crohn's treatment far beyond the strength of supporting evidence. De-implementation matters: an ineffective low-risk drug can still be harmful if it delays effective control of inflammation.

Budesonide retains a role for selected mild-to-moderate ileocecal disease, while systemic corticosteroids remain useful for short-term induction in appropriate moderate-to-severe flares. Corticosteroids are not maintenance therapy. Repeated steroid exposure is a signal that the long-term strategy is failing.

3. Advanced therapy is now a multi-class decision

The therapeutic menu now spans tumor necrosis factor (TNF) antagonists, anti-integrin therapy, interleukin-12/23 and selective interleukin-23 pathway agents, and Janus kinase inhibition. The 2025 AGA guideline recommends infliximab, adalimumab, ustekinumab, risankizumab, mirikizumab, guselkumab or upadacitinib over no treatment for adults with moderate-to-severely active Crohn's disease, while also supporting certolizumab pegol or vedolizumab with more conditional strength.

The practical question is therefore no longer “biologic or no biologic?” but “which mechanism fits this patient?” Choice should incorporate prior biologic exposure, disease phenotype, perianal disease, need for rapid control, comorbid immune-mediated disease, infection risk, malignancy history, pregnancy plans, age, route preference, adherence, access and payer constraints.

For advanced-therapy-naive patients, the AGA guideline stratifies therapies by comparative efficacy based on network meta-analysis. After prior TNF exposure, relative positioning changes. These are population-level comparisons, not guarantees for an individual patient, but they are more useful than treating all advanced agents as interchangeable.

4. Earlier therapy does not eliminate the need for objective monitoring

Crohn's symptoms correlate imperfectly with mucosal inflammation. A patient can feel better while ulceration persists, or remain symptomatic because of a stricture, bile acid diarrhea, IBS overlap or another non-inflammatory mechanism despite inflammatory control. Treat-to-target practice therefore separates symptoms from objective disease activity.

The 2025 ACG guideline supports fecal calprotectin to help distinguish inflammatory from non-inflammatory symptoms and recognizes intestinal ultrasound as a non-invasive monitoring option alongside cross-sectional imaging. Endoscopy remains central for assessing mucosal disease. The target is not merely “the patient feels better”; it is sustained steroid-free clinical control with objective improvement sufficient to reduce long-term complications.

There is, however, legitimate nuance. The 2025 AGA guideline notes uncertainty about whether every patient should be managed to a formal endoscopic-remission target rather than symptomatic remission. That apparent tension is useful rather than confusing: objective monitoring is clearly important, but the evidence base for every treat-to-target escalation decision is still evolving. Shared decision-making and disease severity matter.

5. Intestinal ultrasound is moving into routine practice

A notable diagnostic and monitoring update is greater acceptance of intestinal ultrasound (IUS). It offers real-time, radiation-free assessment of bowel-wall thickness, vascularity and complications in trained hands. Availability and operator expertise remain limiting factors, especially in North America, but its inclusion in the ACG guideline signals a meaningful change in the monitoring toolkit.

Magnetic resonance enterography remains important when small-bowel extent, penetrating complications or strictures need detailed assessment. Computed tomography is useful in acute settings but should not be the default repeated monitoring strategy in young patients when radiation-free alternatives are available.

6. Perianal and fistulizing disease remains phenotype-specific

Perianal Crohn's disease should not be managed as luminal disease alone. Pelvic MRI, examination under anesthesia when appropriate, drainage of abscesses, seton use and coordinated surgical care can be as important as the choice of biologic. Infliximab remains a key evidence-based therapy for fistulizing disease, but optimal outcomes usually require combined medical and surgical strategy rather than medication in isolation.

7. Surgery is not therapeutic failure

Modern Crohn's management has moved away from viewing surgery as something to avoid at all costs. Surgery is appropriate for fibrotic obstruction, uncontrolled penetrating complications, refractory localized disease and other defined indications. In selected patients with localized ileocecal disease, early surgery can be a rational option rather than the endpoint of years of ineffective medication. The clinical objective is bowel preservation and durable disease control, not avoidance of the operating room as an ideological goal.

8. Preventive care is part of IBD therapy

The 2025 ACG preventive-care guideline reinforces that IBD management extends beyond controlling intestinal inflammation. Vaccination, infection screening, skin-cancer prevention, cervical cancer screening, bone health, mental health, smoking cessation and nutrition belong inside routine IBD care. The expanding use of targeted immunosuppression makes this more, not less, important.

What should a modern Crohn's treatment sequence look like?

A practical algorithm

• Confirm active inflammatory disease and define location, behavior, severity and complications before changing therapy.
• Identify prognostic features that justify early advanced treatment rather than prolonged step-up therapy.
• Use corticosteroids, when needed, as short-term induction rather than maintenance.
• Choose advanced therapy by prior exposure, phenotype, comparative efficacy, comorbidities, safety, patient preference and access.
• Monitor symptoms and objective inflammation using fecal calprotectin, endoscopy, intestinal ultrasound or cross-sectional imaging as appropriate.
• If symptoms persist, determine whether the mechanism is active inflammation, fibrosis/stricture, infection, bile acid diarrhea, functional overlap or another cause before escalating immunosuppression.
• Integrate preventive care, nutrition, smoking cessation and surgery into the treatment plan from the beginning.

What has changed most since the older textbook era?

The biggest changes are earlier advanced therapy, far more therapeutic mechanisms, objective monitoring, de-emphasis of mesalamine and a more explicit recognition that delayed control can create structural bowel damage. The therapeutic question is now about positioning and sequencing rather than simply deciding when to “start a biologic.”

What should trainees remember?

Crohn's disease is transmural and heterogeneous. Treat the phenotype and the prognosis, not only the symptom score. A good response means more than temporary steroid-responsive symptom relief. Always ask what objective evidence says about inflammation and whether the patient is accumulating bowel damage.

For practising gastroenterologists, the challenge in 2026 is no longer lack of options. It is choosing among many effective options and switching with purpose when a target is not reached.

Free further reading from Dr. Alan B. R. Thomson

Dr. Thomson's Guideline-Based Management in Gastroenterology and Practice Review in Gastroenterology are available free at GIandHepatology.com. They provide the underlying disease framework and clinical reasoning; current therapeutic choices should be cross-checked against the 2025 ACG and 2025 AGA guidance because the drug landscape has changed substantially.

Frequently asked questions

Do patients with moderate-to-severe Crohn's disease need to fail thiopurines before advanced therapy?

No. Current ACG guidance supports earlier advanced therapy without requiring failure of conventional immunomodulators first in appropriate moderate-to-severe disease.

Is mesalamine still recommended for luminal Crohn's disease?

The 2025 ACG guideline strongly discourages oral mesalamine for induction and maintenance of luminal Crohn's disease because of limited efficacy.

How should response be monitored?

Symptoms should be combined with objective measures such as fecal calprotectin, endoscopy, intestinal ultrasound or cross-sectional imaging, selected for the disease location and clinical question.

Does surgery mean medical treatment failed?

No. Surgery can be the correct disease-modifying strategy for defined stricturing, penetrating or localized disease and should be considered on clinical merit.

References

1. Thomson ABR. Guideline-Based Management in Gastroenterology. CAPstone Academic Publishers; 2015. ISBN 978-1515078623.

2. Thomson ABR. Practice Review in Gastroenterology. CAPstone Academic Publishers; 2014. ISBN 978-1500855321.

3. Lichtenstein GR, Loftus EV Jr, Isaacs KL, et al. ACG Clinical Guideline: Management of Crohn's Disease in Adults. Am J Gastroenterol. 2025;120(6):1225-1264.

4. Scott FI, Ananthakrishnan AN, Click B, et al. AGA Clinical Practice Guideline on Pharmacological Management of Moderate-to-Severe Crohn's Disease. Gastroenterology. 2025. doi:10.1053/j.gastro.2025.09.038.

5. Gordon H, Minozzi S, Kopylov U, et al. ECCO Guidelines on Therapeutics in Crohn's Disease: Medical Treatment. J Crohns Colitis. 2024;18(10):1531-1555. doi:10.1093/ecco-jcc/jjae091.

6. Farraye FA, et al. ACG Clinical Guideline: Preventive Care in Inflammatory Bowel Disease. Am J Gastroenterol. 2025.