A common antibiotic may help Crohn's patients get more out of biologic therapy

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Ability to provide written informed consent prior to any study procedures and willing and able to attend all study visits, comply with the study procedures, read and write in order to complete questionnaires, and be able to complete the study period. * Aged 18 to 80 years of age, inclusive, at the time of signing the informed consent. * Diagnosis of CD with an onset of symptoms for a minimum of 3 months prior to Screening as determined by the investigator based on clinical history, exclusion of infectious causes, and characteristic endoscopic and histologic findings. * Prior decision of starting infliximab or adalimumab therapy (including biosimilar drugs). * Thiopurine and corticosteroid co-therapy will be permitted. Exclusion Criteria: * Inclusion in another interventional study * Patients who cannot provide informed consent and do not have a legal guardian * Patients with perianal involvement who are expected to require antibiotic therapy for their disease * Patients on chronic antibiotic therapy due to any cause * Patients with ongoing fluid collection/abscess either internal or perianal * Known history of allergy to the study intervention formulation or any of its excipients or components of the delivery device * Prolonged QTc interval or conditions leading to additional risk for QT prolongation * Chronic kidney disease stage 5 (GFR \< 10) * Crohn's Disease complication requiring surgical treatment * Planned/ongoing methotrexate co-therapy * Fecal microbiota transplantation within 8 weeks prior to randomization * Participant has any disorder that, in the opinion of the investigator, may compromise the ability to participate in the study * Pregnancy * Patients who received azithromycin therapy in the previous year (we will not exclude prior use of other antibiotic therapy) * Patients who received any antibiotic treatment within 4 weeks prior to randomization * Re-induction of the same anti-TNF medication * Patients who are on chronic therapy which cannot be withheld in one of these medications: colchicine, phenytoin, and digoxin