The evidence
IBD research
26 studies on the treatment, monitoring, surgery, diet and everyday decisions people with Crohn’s and colitis face — grouped by the decision each one speaks to, summarised in plain language, and honest about where a trial found no benefit. Every card links to the paper itself.
What each treatment does
The trials that established each drug against a dummy treatment, so you can see what it did and for how many people. A drug appearing here means it was tested, not that it is the right one for you.
New England Journal of Medicine · Apr 2010
Infliximab, azathioprine, or combination therapy for Crohn’s disease
In adults with moderate-to-severe Crohn’s who had not taken these drugs before, combining infliximab with azathioprine put more people into steroid-free remission at six months (56.8%) than either drug alone — infliximab alone (44.4%) or azathioprine alone (30.0%).
Why it matters
If you and your team are weighing how to start a biologic, whether to pair it with an immunomodulator is part of that conversation.
Read the paperNew England Journal of Medicine · Aug 2013
Vedolizumab as induction and maintenance therapy for ulcerative colitis
Vedolizumab, a gut-selective antibody, beat placebo for ulcerative colitis: 47.1% of people responded at week 6 versus 25.5% on placebo, and at week 52, 41.8% (dosed every 8 weeks) to 44.8% (every 4 weeks) were in remission versus 15.9% who switched to placebo.
Why it matters
If you and your team are weighing a biologic for ulcerative colitis, this is the trial behind vedolizumab, a drug that targets the gut rather than the whole immune system.
Read the paperNew England Journal of Medicine · May 2017
Tofacitinib as induction and maintenance therapy for ulcerative colitis
Tofacitinib, an oral JAK-inhibitor pill, put more people with ulcerative colitis into remission at 8 weeks than placebo (18.5% vs 8.2% in one trial, 16.6% vs 3.6% in a second), and at 52 weeks remission reached 34.3% at the 5 mg dose and 40.6% at 10 mg versus 11.1% on placebo.
Why it matters
If you and your team are considering a tablet instead of an injection or infusion for ulcerative colitis, this is the trial that established the first oral small-molecule option.
Read the paperNew England Journal of Medicine · Sep 2019
Ustekinumab as induction and maintenance therapy for ulcerative colitis
Ustekinumab, which blocks interleukin-12 and -23, worked in ulcerative colitis even after other drugs had failed: remission at week 8 was 15.5–15.6% versus 5.3% on placebo, and among people who responded, week-44 remission was 43.8% (dosed every 8 weeks) or 38.4% (every 12 weeks) versus 24.0% on placebo.
Why it matters
If you and your team are choosing a maintenance biologic for ulcerative colitis, especially after a previous drug stopped working, this trial supports ustekinumab as an option.
Read the paperNew England Journal of Medicine · Sep 2021
Ozanimod as induction and maintenance therapy for ulcerative colitis
Ozanimod, a once-daily pill that traps immune cells in the lymph nodes, beat placebo in ulcerative colitis: remission was 18.4% versus 6.0% after 10 weeks, and 37.0% versus 18.5% at week 52 among people who had responded early.
Why it matters
If you and your team want an oral maintenance option for ulcerative colitis, this trial backs ozanimod, a different class of pill from the JAK-inhibitors.
Read the paperThe Lancet · May 2022
Risankizumab as induction therapy for Crohn’s disease: results from the phase 3 ADVANCE and MOTIVATE induction trials
Risankizumab, which blocks interleukin-23, worked in moderate-to-severe Crohn’s across two trials. In ADVANCE, 45% were in remission at 12 weeks on the 600 mg dose versus 25% on placebo, and gut-lining healing was seen in 40% versus 12%. In MOTIVATE, which enrolled people whose earlier biologics had failed, remission was 42% versus 20%.
Why it matters
If you and your team are looking at a newer biologic for Crohn’s — including after another drug has stopped working — this is the pair of trials behind risankizumab.
Read the paperNew England Journal of Medicine · May 2023
Upadacitinib induction and maintenance therapy for Crohn’s disease
Upadacitinib, a once-daily tablet, put more people with Crohn’s into remission at 12 weeks than placebo (49.5% vs 29.1% in one trial, 38.9% vs 21.1% in a second, which enrolled people whose biologics had failed), with gut-lining improvement in 45.5% versus 13.1%. At one year, remission was 37.3% on the 15 mg dose and 47.6% on 30 mg, against 15.1% on placebo.
Why it matters
If you and your team want a tablet rather than an injection or infusion for Crohn’s, this is the trial that established one.
Read the paperThe Lancet · Apr 2023
Etrasimod as induction and maintenance therapy for ulcerative colitis (ELEVATE): two randomised, double-blind, placebo-controlled, phase 3 studies
Etrasimod, a once-daily pill, beat placebo in ulcerative colitis: 27% were in remission after 12 weeks versus 7%, and 32% versus 7% at one year. A second, shorter study found 25% versus 15% at 12 weeks.
Why it matters
A second daily tablet in the same class as ozanimod, so if you and your team are weighing oral options for colitis, this is the evidence for the newer of the two.
Read the paperNew England Journal of Medicine · Jun 2023
Mirikizumab as induction and maintenance therapy for ulcerative colitis
Mirikizumab, which blocks interleukin-23, put 24.2% of people with ulcerative colitis into remission at 12 weeks versus 13.3% on placebo. Among those who responded and carried on, 49.9% were in remission at week 40 versus 25.1%.
Why it matters
If you and your team are choosing a biologic for colitis, this is the trial behind one of the newest, and a reminder that the induction numbers and the maintenance numbers answer different questions.
Read the paper
One treatment against another
Trials that put two real drugs side by side, which is much rarer than testing one against a placebo — and the only kind of evidence that can say which of two options did better.
New England Journal of Medicine · Sep 2019
Vedolizumab versus adalimumab for moderate-to-severe ulcerative colitis
Head-to-head in ulcerative colitis, vedolizumab beat adalimumab at one year: 31.3% were in remission versus 22.5% (difference 8.8 percentage points, P=0.006), and more had a healed gut lining (39.7% vs 27.7%). Adalimumab did better on one measure — steroid-free remission, 21.8% versus 12.6%.
Why it matters
Direct comparisons between two real drugs are rare. If you and your team are choosing between these for colitis, this is the trial that put them side by side — including the one measure where the result went the other way.
Read the paperThe Lancet · Jun 2022
Ustekinumab versus adalimumab for induction and maintenance therapy in biologic-naive patients with moderately to severely active Crohn’s disease (SEAVUE)
Head-to-head in people with Crohn’s who had never had a biologic, ustekinumab and adalimumab worked about equally well: 65% (124 of 191) were in remission at one year on ustekinumab versus 61% (119 of 195) on adalimumab, a difference that was not statistically significant.
Why it matters
If you and your team are picking a first biologic for Crohn’s, this rare direct comparison suggests both of these drugs are strong starting options rather than one clearly winning.
Read the paperNew England Journal of Medicine · Jul 2024
Risankizumab versus ustekinumab for moderate-to-severe Crohn’s disease
Compared directly in people with Crohn’s whose anti-TNF treatment had failed, risankizumab matched ustekinumab on remission at 24 weeks (58.6% vs 39.5%) and beat it on healed gut lining at 48 weeks (31.8% vs 16.2%, P<0.001).
Why it matters
If an anti-TNF drug has stopped working for your Crohn’s and you and your team are choosing what comes next, this trial compared the two obvious candidates against each other rather than against a placebo.
Read the paperThe Lancet · Jun 2017
Switching from originator infliximab to biosimilar CT-P13 compared with maintained treatment with originator infliximab (NOR-SWITCH): a 52-week, randomised, double-blind, non-inferiority trial
Switching from the original infliximab to a cheaper biosimilar (CT-P13) held up over a year: disease worsened in 30% of the switch group versus 26% who stayed on the original (adjusted difference -4.4%, 95% CI -12.7 to 3.9), within the pre-set margin for being no worse.
Why it matters
If your team suggests moving you from an original biologic to a biosimilar to save cost, this trial found switching did not measurably reduce how well the drug worked.
Read the paper
Monitoring, and what treatment aims at
Why a clinic measures inflammation rather than going on how you feel, and what the agreed targets of treatment actually are.
The Lancet · Dec 2017
Effect of tight control management on Crohn’s disease (CALM)
When Crohn’s treatment was stepped up based on inflammation markers — faecal calprotectin and CRP — as well as symptoms, more people had healed gut lining at one year (46%) than when treatment followed symptoms alone (30%).
Why it matters
It is the evidence behind why a clinic tracks calprotectin and CRP, not just how you feel day to day.
Read the paperGastroenterology · Apr 2021
STRIDE-II: determining therapeutic goals for treat-to-target strategies in IBD (IOIBD)
An international panel of 89 IBD experts (agreeing when at least 75% scored a statement highly) set shared treatment goals: symptom relief and normal blood and stool markers as short-term targets, and lasting clinical remission plus healing seen on endoscopy as the long-term targets to aim treatment at.
Why it matters
If you and your team are setting goals for your IBD care, this consensus explains why the aim is measured healing and normal markers, not only feeling better day to day.
Read the paper
Surgery, and what follows it
Evidence on when an operation is a reasonable first choice rather than a last resort, and on what happens in the years after one.
The Lancet Gastroenterology & Hepatology · Nov 2017
Laparoscopic ileocaecal resection versus infliximab for terminal ileitis in Crohn’s disease (LIR!C): a randomised controlled, open-label, multicentre trial
For limited Crohn’s at the end of the small bowel that had failed standard drugs, surgery to remove the diseased segment gave quality-of-life scores no different from starting infliximab (IBDQ 178.1 vs 172.0 at 12 months; difference 6.1, p=0.25), making early surgery a reasonable alternative rather than a last resort.
Why it matters
If you and your team are facing a short segment of Crohn’s that is not responding to medication, this trial shows surgery is a legitimate first-line choice, not only a fallback.
Read the paperThe Lancet Gastroenterology & Hepatology · Oct 2020
Laparoscopic ileocaecal resection versus infliximab for terminal ileitis in Crohn’s disease: retrospective long-term follow-up of the LIR!C trial
Followed up a median of five years later, none of the people who had the diseased segment removed needed a second operation, and 42% needed no further Crohn’s medication at all. Of those who started infliximab instead, 48% went on to have surgery anyway.
Why it matters
The long view on the same decision, and the answer to the obvious worry about choosing surgery early: in this group it did not lead to more surgery later.
Read the paperThe Lancet · Apr 2015
Crohn’s disease management after intestinal resection: a randomised trial (POCER)
After Crohn’s surgery, checking with a colonoscopy at 6 months and stepping up treatment if disease was returning cut the Crohn’s coming back: endoscopic recurrence at 18 months was 49% with this active monitoring versus 67% with standard drug treatment alone (p=0.03).
Why it matters
If you or your team are planning care after bowel surgery for Crohn’s, this trial supports scheduled scope checks and adjusting treatment early rather than waiting for symptoms to return.
Read the paper
Diet and the microbiome
The randomised trials, including the ones where the stricter, harder option did no better. Note what each trial measured: easing symptoms and healing inflammation are different results.
Gastroenterology · Sep 2021
A randomized trial comparing the Specific Carbohydrate Diet to a Mediterranean diet in adults with Crohn’s disease
The demanding Specific Carbohydrate Diet was no better than the more liveable Mediterranean diet for easing Crohn’s symptoms at six weeks (46.5% vs 43.5%) — a reason not to take on the stricter diet expecting more.
Why it matters
Useful if you are deciding whether a strict elimination diet is worth it — here, harder did not mean better.
Read the paperGastroenterology · Aug 2019
Crohn’s disease exclusion diet plus partial enteral nutrition induces sustained remission in a randomized controlled trial
In children with mild-to-moderate Crohn’s, a whole-food exclusion diet plus partial formula was far easier to stick with than formula-only feeding (tolerated by 97.5% vs 73.6%) and led to more steroid-free remission at week 12 (75.6% vs 45.1%, p=0.01).
Why it matters
If you or your team are considering dietary treatment for Crohn’s, this trial shows a structured whole-food plan can rival exclusive formula feeding while being much easier to follow.
Read the paperGastroenterology · Jan 2020
Effects of low FODMAP diet on symptoms, fecal microbiome, and markers of inflammation in patients with quiescent inflammatory bowel disease in a randomized trial
In people whose IBD was quiet but who still had gut symptoms, more got adequate relief on a low-FODMAP diet than on a control diet (14 of 27, 52%, versus 4 of 25, 16%; P=.007). The fall in overall symptom-severity scores was larger on the low-FODMAP diet but was not statistically significant.
Why it matters
This is the trial for the gap a lot of people fall into — scopes and bloods settled, gut still unhappy. Note what it measured: symptom relief, not healing.
Read the paperThe Lancet · Mar 2017
Multidonor intensive faecal microbiota transplantation for active ulcerative colitis: a randomised placebo-controlled trial
Intensive faecal transplant from multiple donors reached the trial’s main goal in 11 of 41 people with active ulcerative colitis (27%) versus 3 of 40 given placebo (8%) — a real effect, in a trial of 81 people, for a treatment that is not standard care.
Why it matters
Microbiome treatments attract a lot of claims and very few randomised trials. This is one of them, and its size is part of what it tells you.
Read the paper
Living with IBD
Mental health, smoking, pregnancy and anaemia — the parts of having IBD that happen outside a clinic appointment, where there is real evidence.
The Lancet Gastroenterology & Hepatology · Oct 2023
Efficacy of psychological therapies in people with inflammatory bowel disease: a systematic review and meta-analysis
Across 25 trials, talking therapies gave a short-term lift to anxiety, depression, stress and quality of life — but did not change measured disease activity. They help how you feel, not the inflammation itself.
Why it matters
A reason to take mental-health support seriously in its own right, with honest expectations about what it does and does not change.
Read the paperGastroenterology · Apr 2001
Smoking cessation and the course of Crohn’s disease: an intervention study
Among people with Crohn’s who stopped smoking for more than a year, the risk of a flare dropped to match people who had never smoked, and was lower than in those who kept smoking.
Why it matters
For people with Crohn’s who smoke, stopping is one of the few lifestyle changes with a measured effect on the disease.
Read the paperAmerican Journal of Gastroenterology · Mar 2024
Maternal and neonatal outcomes in vedolizumab- and ustekinumab-exposed pregnancies: results from the PIANO registry
Across 1,669 pregnancies followed in the PIANO registry, babies exposed in the womb to vedolizumab or ustekinumab showed no increased risk of miscarriage, being small for dates, low birth weight, a neonatal intensive care stay, birth defects or restricted growth.
Why it matters
Whether to stay on a biologic through pregnancy is one of the hardest questions IBD raises, and it is usually asked with very little data. This is the registry evidence for two of the newer drugs.
Read the paperGastroenterology · Sep 2011
FERGIcor, a randomized controlled trial on ferric carboxymaltose for iron deficiency anemia in inflammatory bowel disease
For the iron-deficiency anaemia that comes with IBD, one intravenous iron worked better than another: with ferric carboxymaltose, 65.8% had a haemoglobin response versus 53.6% on iron sucrose (P=.004), and 72.8% reached a normal haemoglobin versus 61.8% (P=.015).
Why it matters
Anaemia is one of the most common things IBD does to people outside the gut, and it is a large part of the tiredness. Which iron, and by which route, is a decision with evidence behind it.
Read the paper
What this is, and is not
Each summary links to the study it came from. This is research, not medical advice — what it means for you is a conversation with your clinician.