Guselkumab

The goal of this observational study is to evaluate the response of guselkumab in adult patients with Crohn's disease (CD) as measured on intestinal ultrasound (IUS), the relative quantities of CD64 in endoscopic tissue biopsies, and the protein signature in the blood of patients with and without therapy response. The main question it aims to answer is:
* What is the proportion of ileal Crohn's disease patients with and without strictures who achieve an intestinal ultrasound response?
* What is the quantity of CD64 in tissue in CD patients at baseline and at week 52 with and without IUS response?
* Are there proteomic signatures in blood of CD patients that respond to GUS?

Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis (IPAA) is considered the procedure of choice in patients with ulcerative colitis (UC) refractory to medical therapy or with neoplasia. The most common complication after IPAA is the development of pouchitis. Pouchitis is clinically characterized by variable symptoms including increased stool frequency, altered consistency, bloody stools, abdominal cramping, urgency, and incontinence. Symptomatic pouchitis longer than four weeks is considered chronic pouchitis.
The conventional treatment for acute and chronic pouchitis is antibiotics, such as metronidazole and ciprofloxacin. The disease course of antibiotic responsive pouchitis may evolve into antibiotic dependent (requiring antibiotic maintenance therapy) pouchitis and then antibiotic refractory (no response to antibiotic treatment) pouchitis. Although many patients respond to antibiotic therapy, there is also evidence that suggest that aberrant regulation of the mucosal immune system might play a part in the pathogenesis of pouchitis arising from an abnormal mucosal immune response to a dysbiosis of the pouch microbiota. If individuals fail to respond to antibiotics, anti-tumor necrosis factor (anti-TNF) agents and vedolizumab have been proposed for the treatment of chronic pouchitis.
Guselkumab, an interleukin-23 (IL-23) p19 subunit antagonist monoclonal antibody, is proven to be efficacious in patients with moderately-to-severely active UC. Efficacy of guselkumab in treating UC has been shown in multiple large clinical trials. However, patients with pouchitis were never the targeted population and were even often excluded from the trials.
Pouchitis becomes a chronic problem with a huge impact in the quality of life of these patients. The incidence of pouchitis has been rising in the last decades. This increase might be explained by a change in dietary habits of this population.
This open label single center trial at UZ Leuven aims to evaluate the efficacy and safety of guselkumab in the treatment of chronic antibiotic refractory pouchitis during a 48-week treatment period, with or without a dietary intervention. Twenty subjects with a proctocolectomy and IPAA for UC who have developed chronic or relapsing pouchitis will be enrolled.