Antibiotic treatment for 1 day versus 4-7 days in patients with acute cholangitis after adequate endoscopic biliary drainage (COBRA): study protocol for a randomized controlled trial

BackgroundAcute cholangitis is an infection of the biliary tract that is managed with adequate biliary drainage combined with antibiotic treatment. The international Tokyo Guidelines 2018 recommend 4 to 7 days of antibiotic treatment after adequate biliary drainage, but observational data suggest shorter treatment may be sufficient. We assessed whether 1 day of antibiotic treatment is non-inferior to 4-7 days of antibiotic treatment for acute cholangitis after adequate biliary drainage.MethodsThe COBRA-trial is a multicentre, open-label, parallel group randomized controlled non-inferiority trial with blinded outcome assessment. A total of 416 patients with acute cholangitis will be randomly assigned in a 1:1 ratio to the intervention group (1 day of antibiotic treatment after adequate biliary drainage) or to the control group (4-7 days of antibiotic treatment after adequate biliary drainage). Patients with acute cholangitis due to common bile duct stones, benign or malignant distal biliary obstruction, or distal biliary stent dysfunction are eligible. Randomization will take place once adequate biliary drainage is achieved by ERCP. Main exclusion criteria are concomitant pancreatitis, liver abscess, cholecystitis, and another infectious diagnosis at the time of randomization, use of systemic maintenance antibiotics, and specific immunosuppressants. Patients will be stratified for blood culture results at the time of randomization and aetiology of cholangitis. The primary endpoint is clinical cure, defined as the patient being symptom-free by day 14, with no relapse or death occurring by day 30. Secondary endpoints include 30-day and 90-day all-cause mortality, relapse of cholangitis by day 90, time from ERCP to first relapse, any other subsequent infection requiring antibiotic treatment within 90 days, duration of initial hospital stay, number of days treated with antibiotics by day 30, subsequent infections with multidrug resistant (MDR) bacteria, quality of life, and cost-effectiveness.DiscussionThis trial assesses whether a short course of antibiotic treatment for acute cholangitis is as safe and effective compared to a longer course of antibiotic treatment. If confirmed, the results could substantially reduce antibiotic exposure and healthcare resource utilization, thereby contributing to global efforts to minimize unnecessary antibiotic treatment.Trial registrationClinicalTrials.gov NCT05750966, registered on March 2nd, 2023.