Plastic pigtail vs lumen-apposing metal stents for drainage of walled-off necrosis (PROMETHEUS study): an open-label, multicenter randomized trial.

BACKGROUND: Lumen-apposing metal stents (LAMS) have displaced double-pigtail plastic stents (DPS) as the standard treatment for walled-off necrosis (WON),ß but evidence for exclusively using LAMS is limited. We aimed to assess whether the theoretical benefit of LAMS was superior to DPS. METHODS: This multicenter, open-label, randomized trial was carried out in 9 tertiary hospitals. Between June 2017, and Oct 2020, we screened 99 patients with symptomatic WON, of whom 64 were enrolled and randomly assigned to the DPS group (n = 31) or the LAMS group (n = 33). The primary outcome was short-term (4-weeks) clinical success determined by the reduction of collection. Secondary endpoints included long-term clinical success, hospitalization, procedure duration, recurrence, safety, and costs. Analyses were by intention-to-treat. CLINICALTRIALS: gov, NCT03100578. RESULTS: A similar clinical success rate in the short term (RR, 1.41; 95% CI 0.88-2.25; p = 0.218) and in the long term (RR, 1.2; 95% CI 0.92-1.58; p = 0.291) was observed between both groups. Procedure duration was significantly shorter in the LAMS group (35 vs. 45-min, p = 0.003). The hospital admission after the index procedure (median difference, - 10 [95% CI - 17.5, - 1]; p = 0.077) and global hospitalization (median difference - 4 [95% CI - 33, 25.51]; p = 0.82) were similar between both groups. Reported stent-related adverse events were similar for the two groups (36 vs.45% in LAMS vs. DPS), except for de novo fever, which was significantly 26% lower in LAMS (RR, 0.26 [0.08-0.83], p = 0.015). CONCLUSIONS: The clinical superiority of LAMS over DPS for WON therapy was not proved, with similar clinical success, hospital stay and similar safety profile between both groups, yet a significant reduction in procedure time was observed. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, NCT03100578.

Multicenter study of plastic vs. self-expanding metal stents in endoscopic ultrasound-guided drainage of walled-off pancreatic necrosis - PROMETHEUS: a randomized controlled trial protocol.

BACKGROUND: It seems that lumen-apposing metal stents (LAMS) are displacing plastic stents in the therapy of pancreatic-fluid collection in walled-off necrosis (WON). To date, there is no quality of evidence to recommend LAMS as the standard treatment in the management of WON. The theoretical benefit of LAMS over plastic stents needs to be proven. METHODS/DESIGN: This is a randomized controlled, multicenter, prospective clinical trial with two parallel groups, without masking. One-hundred and fourteen patients with WON will undergo endoscopic ultrasound (EUS)-guided transmural draining in nine tertiary hospitals in Spain and will be randomized to the LAMS or plastic-stent group. The primary endpoint is the short-term (4 weeks) clinical success determined by the reduction of the collection (to < 50% or < 5 cm in size), along with clinical improvement. Secondary endpoints: long-term (4 months) clinical success (total resolution or 5 cm), procedure duration, level of difficulty, safety, and recurrences. DISCUSSION: The PROMETHEUS trial has been designed to determine whether LAMS are superior to plastic stents in EUS-guided transmural drainage of WON. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT03100578. Registered on 4 April 2017. https://clinicaltrials.gov/ct2/home.