Clinical Trial Testing Whether Targeted Antibiotic Prophylaxis Can Reduce Infections After Cystectomy Compared to Empiric Prophylaxis

Surgical removal of the urinary bladder (cystectomy) remains one of the most complex abdominal surgeries. The procedure carries a high risk of infectious complications, and nearly one in three patients are readmitted with infection within 90 days of surgery. Due to lack of high-evidence research on prophylactic antibiotic strategies after cystectomy, the timing, duration, and type of prophylaxis varies considerably across surgical centres and nearly always encompasses a one-size-fits-all approach with an empiric antibiotic. With antibiotic stewardship gaining ground, both patients and the community at large may benefit from a more individualised targeted approach.

The investigators aim to reduce infectious complications in the postoperative course of cystectomy by conducting an investigator-initiated randomised clinical trial testing superiority of targeted antibiotic prophylaxis after cystectomy against the current standard-of-care empiric prophylaxis.

The REINFORCE trial is a multicentre, open-label, randomised, superiority trial. Cystectomy patients will be randomly assigned with a 1:1 allocation to receive one of the following orally administered antibiotic treatments on the day of ureteral stent removal: (A) Standard-of-care arm: Three doses of pivmecillinam 400mg or (B) Intervention arm: Single-day treatment of an antibiotic susceptible to the bacteria detected in a postoperative urine sample collected during index hospitalisation. If no bacteria are detected the participant will not receive antibiotics.

Patients scheduled for cystectomy will be screened for inclusion in the urological outpatient clinic at their allocated hospital. Patients who meet the inclusion and exclusion criteria will be informed of the trial and invited to participate. After informed consent, a preoperative urine culture will be collected and analysed for microbials, and two validated EORTC quality of life questionnaires will be filled out electronically.

After cystectomy during index hospitalisation, participants will deliver a postoperative urine sample, which will be analysed for bacteria and antibiotic susceptibility, and participants will be randomised into one of the two arms.

Apart from the intervention, all participants will follow the standard-of-care pre-, peri-, and postoperative treatment as per hospital guidelines. Participants will be followed for 90 days postoperatively, where complication rates and readmission rates will be collected from the Electronic Medical Records, and participants will be asked to fill out the quality of life questionnaires again.

The primary outcome is infection-related hospital readmissions within 90 days of cystectomy. We aim for an absolute risk reduction in the infection-related readmission rate of 15% (from 29% to 14%), corresponding to a number needed to treat of six patients to reduce one infection-related readmission. With a 1:1 allocation, changing block size, power of 80%, one-sided test, significance level of 0.024 accounting for alpha spending of two sequential analyses using the O'Brien-Fleming boundaries, and an anticipated dropout rate of 5%, a total of 248 participants (124 per arm) needs to be randomised.

All randomised participants will follow an intention-to-treat analysis, regardless of adherence to protocol. If some participants do not receive the allocated treatment, a per-protocol sub-analysis will be performed. The trial utilises a group sequential design to allow for the possibility of early stopping for efficacy, futility, or safety at interim analysis, which will be performed after 50% of participants have been followed for 90 postoperative days.

International guidelines are currently unable to make evidence-based recommendations on how to avoid infections after cystectomy and current antibiotic prophylactic strategies vary greatly across centres. By performing a large multicentre randomised trial to test targeted antibiotic prophylaxis, the investigators aim to improve recovery for patients who have undergone cystectomy by reducing the risk of infections in the months after surgery.

• Postoperative complications [Time frame: 30 and 90 days after surgery]
• Postoperative readmissions [Time frame: 30 and 90 days after surgery]
• Days alive and out of hospital [Time frame: 30 and 90 days after surgery]
• Quality of life [Time frame: 90 days after surgery]
• Quality of life [Time frame: 90 days after surgery]
• Microbiological findings [Time frame: 90 days after surgery]
• Antimicrobial treatment [Time frame: 90 days after surgery]