Study of mirikizumab versus azathioprine in newly diagnosed moderate-to-severe Crohn’s disease patients

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What is this study about?

Crohn’s disease is a long‑lasting condition that causes inflammation and pain in the digestive tract. In this study, one group receives the experimental medicine mirikizumab, which is given by injection, while another group receives the standard oral medication azathioprine together with short courses of glucocorticoids, a type of steroid used to reduce inflammation.

The aim of the trial is to find out whether the mirikizumab approach leads to a higher rate of deep remission after one year. Deep remission means that a person’s symptoms are low enough to score below 150 on the CDAI (a questionnaire that rates Crohn’s disease activity), that the intestinal lining looks normal on a scope with a score of 2 or less on the SES‑CD system, and that no steroids, surgeries, fistulas, or new narrowings have been needed. Participants are followed for about 52 weeks, with regular clinic visits for medication administration, safety checks, and routine assessments of symptoms and gut health.

1 enrollment and randomization

after joining the study, you will be assigned by a computer system to one of two treatment groups. the groups are mirikizumab (test) or azathioprine with oral glucocorticoid (comparator). the assignment is random and you will not know which group you are in until treatment starts.

2 baseline assessments

before any medication is given, a series of examinations will be performed. these include a physical check, blood tests, and an endoscopic examination of the intestine to confirm the severity of crohn’s disease.

3 start of study medication – induction phase

if you are assigned to the mirikizumab group, the first dose will be a subcutaneous injection of 200 mg (milligrams). subcutaneous means the medicine is injected just under the skin.

if you are assigned to the comparator group, you will begin oral azathioprine at a dose of 2.5 mg per kilogram of body weight each day, together with an oral glucocorticoid tablet of 60 mg each day. oral means the medicine is taken by mouth.

4 induction monitoring

during the first weeks after the initial dose, you will attend clinic visits to check how you are responding to the medication and to monitor safety. the exact timing of these visits follows the study schedule.

5 maintenance therapy

for participants receiving mirikizumab, after the induction dose the maintenance dose is a subcutaneous injection of 100 mg given regularly as defined in the protocol. the protocol also includes an intravenous infusion of 900 mg at a specified time point; intravenous means the medicine is given through a vein.

for participants receiving the comparator, azathioprine continues at the same daily dose of 2.5 mg/kg. the oral glucocorticoid is tapered according to the protocol, meaning the dose is gradually reduced and eventually stopped.

6 regular follow‑up visits

throughout the 52‑week study period you will have scheduled visits at regular intervals (for example, every 4 to 8 weeks). at each visit you will undergo symptom questionnaires, blood tests, and possibly repeat endoscopy to assess disease activity.

any adverse effects or new symptoms will be recorded and managed according to study guidelines.

7 final assessment at week 52

at the end of week 52, a comprehensive evaluation will be performed. this includes a clinical assessment to determine if the crohn’s disease activity score (cdaI) is below 150, an endoscopic examination to confirm an ses‑cd score of 2 or less with no deep ulcers, and confirmation that no systemic glucocorticoids have been used in the prior 8 weeks.

the outcome measured is deep remission, meaning all of the above criteria are met without the need for surgery, fistula drainage, or new strictures.

Who Can Join the Study?

Give written informed consent before any study procedures are done.
Stop taking oral budesonide at least 2 weeks before the screening colonoscopy (you may switch to prednisolone); also stop oral mesalamine at least 2 weeks before the colonoscopy.
Show evidence of active Crohn’s disease, which means:
- A CDAI score between 220 and 500 (the Crohn’s Disease Activity Index is a number that reflects how severe the symptoms are).
- Either a blood test showing high CRP (C‑reactive protein, a marker of inflammation) or a stool test showing fecal calprotectin greater than 250 µg/g (a marker of gut inflammation).
- A colonoscopy showing disease activity, measured by a SES‑CD score of 4 or more if only the ileum is involved, or 6 or more if the colon or both colon and ileum are involved (the SES‑CD is a score that doctors give after looking at the intestine).
No actively draining fistula (an abnormal passage that can form between the intestine and other organs or the skin) at screening or baseline.
No previous surgery related to Crohn’s disease.
Willing and able to complete all study visits, including the colonoscopy and daily diary entries.
Agree to follow the study’s contraception requirements.
Be between 18 and 75 years old.
Never have used thiopurines (such as azathioprine or 6‑mercaptopurine) or methotrexate before.
Never have used any advanced therapies (targeted biologic drugs or small‑molecule drugs) for Crohn’s disease or any other condition.
Have “early disease,” meaning Crohn’s disease was diagnosed no more than 12 months ago and at least 4 weeks before randomization.
Previously taken 5‑aminosalicylate (5‑ASA) and/or oral glucocorticoids (steroid medicines) but did not respond well, lost response, or could not tolerate them.
If you are taking systemic glucocorticoids at screening, the total exposure must be 8 weeks or less, and the dose of prednisolone (or equivalent) must be 20 mg per day or less and stable for at least 2 weeks before the colonoscopy.

Who Cannot Join the Study?

Having a very severe flare of Crohn’s disease that needs emergency hospital care or urgent surgery right away (for example, a blockage, a hole in the intestine, a draining fistula, uncontrolled infection, or toxic megacolon).
Having a hidden (latent tuberculosis) infection.
Planning to receive any live or weakened (live‑attenuated) vaccines (including the BCG vaccine for TB) during screening or while in the study.
Having a serious fungal infection (systemic mycoses) or a parasite infection (parasitosis).
Having any other serious or uncontrolled illness that could increase risk or make it hard to see if the study works, such as heart, brain, lung, liver, kidney, hormone, blood, nerve problems, or active cancer.
Being known to be allergic (systemic hypersensitivity) to any study drug, any of its ingredients, or having had a severe allergic reaction to medicines called monoclonal antibodies in the past.
Being a woman who is pregnant, breastfeeding, or planning to become pregnant.
Being an employee of Lilly or the study sites, or being an immediate family member of those employees.
Having taken part in another clinical trial with an experimental drug or unapproved drug use within the past 12 weeks, or being enrolled in any other study at the same time.
Not willing or able to use the electronic diary (eDiary) or follow other study procedures for the whole study period.
Being under a legal order that places you in an institution (for example, prison or mandated care).
Using oral or rectal 5‑ASA medicines or rectal steroids within 2 weeks before the screening colonoscopy.
Having a history of cancer, except for non‑melanoma skin cancer that has been successfully treated and cured.
Planning to have surgery before the randomization visit (Week 0) or expecting surgery soon.
Having a known deficiency of the enzyme thiopurine methyltransferase (TPMT) or a known mutation in the NUDT15 gene.
Having inherited problems that prevent the body from processing certain sugars, such as galactose intolerance, total lactase deficiency, or glucose‑galactose malabsorption.
Having a diagnosis that is not Crohn’s disease, such as ulcerative colitis, indeterminate colitis, microscopic colitis, or other similar gut inflammation.
Having an active infection that is clinically important, such as hepatitis B, hepatitis C, HIV/AIDS, or active tuberculosis.
Having detectable hepatitis B virus DNA or hepatitis C virus RNA in the blood at screening.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Gastropraxis Magdeburg	Magdeburg	Germany
CED Studienzentrum Karlshorst, Dr. med., Thomas Brunk, Gastroenterologie Berlin	Berlin	Germany

Other Sites

Site Name	City	Country
Specialist Internal Medicine Practice	Hamburg	Germany
Gastropraxis an der St. Barbara-Klinik	Hamm	Germany
Universitaetsklinikum Schleswig-Holstein AöR	Kiel	Germany
Pggycrhs fkm Gsziioebxmlbkjpx	Hanover	Germany

Trial status

Country	Status	Recruitment Start
Germany	Not yet recruiting	01.07.2026

Trial locations

Investigated drugs:

Mirikizumab is a biologic medicine that works by blocking a protein involved in the inflammation process of Crohn’s disease. In this study it is given by injection, either under the skin or into a vein, and is used both to start treatment (induction) and to keep the disease under control over time.

Azathioprine is an oral medication that suppresses the immune system. By slowing down immune activity, it helps to reduce the inflammation that causes Crohn’s disease symptoms. Participants in the trial take this pill regularly as part of the standard treatment plan.

Glucocorticoids are a type of steroid medicine taken by mouth that quickly lower inflammation. In the trial they are used together with azathioprine as part of the usual care for Crohn’s disease, helping to control flare‑ups while other treatments work.

Investigated diseases:

Crohn's disease

Crohn’s disease – Crohn’s disease is a long‑lasting inflammation of the digestive tract that can affect any part from mouth to anus, most often the end of the small intestine and the colon. It causes abdominal pain, diarrhea, and weight loss, and the inflamed areas can become thickened and scarred over time. The condition usually follows a pattern of flare‑ups when symptoms worsen, followed by periods when they improve. As the disease continues, the intestinal walls may narrow, making it harder for food to pass. In some cases, abnormal connections called fistulas can develop between the intestine and nearby organs.

Trial ID:

2026-525191-26-00

Protocol code:

MIRAGE

Trial Phase:

Therapeutic confirmatory (Phase III)

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Study of mirikizumab versus azathioprine in newly diagnosed moderate-to-severe Crohn’s disease patients

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?