SOIBD Collagenous Colitis Maintenance Study

Inclusion criteria

• Signed informed consent,
• Patients aged >= 18 years,
• Histologically established diagnosis of collagenous colitis (CC) defined as:

• Thickened sub-epithelial collagen layer >= 10 µm on well-orientated sections,
• Increased amount of inflammatory cells indicating chronic inflammation in the lamina propria,
• History of non-bloody, watery diarrhoea for more than 2 weeks prior screening in patients with newly diagnosed collagenous colitis, or history of clinical relapse for more than 1 week prior screening in patients with previously established collagenous colitis,
• A mean of >= 3 stools/day, thereof a mean of >= 1 watery stools/day, during the week prior baseline,
• Women of child-bearing potential and being heterosexually active have to apply appropriate contraceptive methods, e.g., hormonal contraception, intrauterine device (IUD), double-barrier method of contraception (e.g., use of a condom and spermicide), or partner has undergone vasectomy. The investigator is responsible for determining whether the subject has adequate birth control for study participation.

Exclusion criteria

• Other significant abnormalities at colonoscopy that may have been the cause of diarrhoea, with the exception of colonic diverticulosis and polyps < 2 cm,
• Infectious cause of diarrhoea,
• Untreated active celiac disease,
• Clinical suspicion of drug-induced collagenous colitis,
• Any severe concomitant cardiovascular, renal, endocrine, or psychiatric disorder,
• Abnormal hepatic function (ALT or ALP > 2.5 x upper limit of normal [ULN]), liver cirrhosis, or portal hypertension,
• Local intestinal infection,
• Radiation therapy towards the abdominal or pelvic region,
• Diabetes mellitus, infection, glaucoma, tuberculosis, peptic ulcer disease, or hypertension if careful medical monitoring is not ensured,
• Known established cataract,
• Known hereditary problems of galactose or fructose intolerance, glucose-galactose malabsorption, sucrase-isomaltase insufficiency, Lapp lactase deficiency, or congenital lactase deficiency,
• Established osteoporosis with T-score < -2.5,
• Pregnancy or lactation,
• History of cancer in the last five years,
• History of significant bowel resection,
• Therapy with immunomodulators (azathioprine, 6-mercaptopurine, or methotrexate) in the last 3 months,
• Treatment with oral, rectal, or intravenous corticosteroids including budesonide in the last month,
• Known intolerance/hypersensitivity to study drug or drugs of similar chemical structure or pharmacological profile,
• Patients who are unable to adhere to the study visit schedule and other protocol requirements according to the judgement of the investigator,
• Participation in another clinical trial within the last 30 days, simultaneous participation in another clinical trial, or previous participation in this trial.