SAR444336 to help adults with microscopic colitis stay in remission while on budesonide.

Inclusion Criteria:

* Participants with histologically confirmed diagnosis of microscopic colitis (including all histological sub-types).
* Receiving budesonide therapy.
* Documented clinical remission from 2 weeks before screening.
* At least 1 microscopic colitis relapse in the last 8 months prior to screening that required treatment with budesonide.
* Body mass index within the range 18 to 35 kg/m2 (inclusive) at screening visit.
* All contraceptive methods used by participants should be consistent with local regulations regarding the methods of contraception.

Exclusion Criteria:

* Significant neutrophilic/eosinophilic infiltration, crypt abscesses, granulomata, or any evidence of IBD other than microscopic colitis.
* Evidence of infectious diarrhea in the 3 months prior to randomization.
* Other active diarrheal conditions or suspicion of drug--induced microscopic colitis at screening, or diarrhea predominant irritable bowel syndrome.
* Any current active viral, bacterial, or fungal infection or any medically relevant infection having occurred within 3 weeks before randomization.
* Previous bowel surgeries.
* Planned surgery while receiving study treatment. Dental surgeries or other types of minor surgery requiring only local anesthetic are allowed.
* Other immunologic disorder, except controlled diabetes or thyroid disorder receiving appropriate treatment.
* Presence or history of drug hypersensitivity associated with eosinophilia in the past 6 months.
* History or presence of alcohol or illicit drug abuse within the past 2 years.
* Excessive consumption of beverages containing xanthine bases.
* History of solid organ transplant.
* Active malignancy, lymphoproliferative disease, or malignancy in remission for less than 2 years, except adequately treated (cured) localized carcinoma in situ of the cervix or ductal breast, or squamous cell carcinoma, or basal cell carcinoma of the skin.
* Have experienced any of the following within 12 months before screening: myocardial infarction, unstable ischemic heart disease, stroke, or New York Heart Association Stage III or IV heart failure.
* Participants with a history or presence of another significant illness such as renal, neurological, ophthalmological, psychiatric, endocrine, cardiovascular, gastrointestinal, hepatic disease, metabolic, pulmonary or lymphatic.
* Live attenuated vaccines within 6 weeks of randomization and during the study.
* Currently receiving or had treatment within 12 months prior to screening with B or T cell depleting agents.
* At screening, have abnormal laboratory values or ECG abnormalities.
* Participants with recent tuberculosis (TB) vaccination or positive TB test results.

The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.