Background: Pouchitis is common following total proctocolectomy for ulcerative colitis (UC) and ileal pouch-anal anastomosis (IPAA) and generally responds to antibiotics. However, up to 20% of patients develop either antibiotic-dependent or antibiotic-refractory pouchitis, collectively referred to as chronic pouchitis.

Methods: We report our preliminary induction results from a multi-center open label induction with randomized withdrawal trial to assess the efficacy of tofacitinib in chronic pouchitis. All eligible participants received 10mg tofacitinib twice daily for 8 weeks, with an additional 8 weeks of therapy given to patients with an inadequate initial clinical response. The primary endpoint was clinical response (a reduction of clinical PDAI>2) at week 8. Secondary endpoints included endoscopic response (a reduction of endoscopic PDAI>2), mPDAI remission (modified pouchitis disease activity index (mPDAI)<4 and a reduction of mPDAI>2), mPDAI response (a reduction of mPDAI>2) and improvement in health-related quality of life (HRQoL) using the short inflammatory bowel disease questionnaire (SIBDQ). Serum cytokine levels was analyzed using LEGENDplex human inflammation panel 1. Univariate analysis was performed to identify clinical and biochemical predictors of response to tofacitinib.

Results: A total of 33 patients with chronic pouchitis (Table 1) were included in the preliminary analysis. The clinical and endoscopic response rates at week 8 were 55% and 58% respectively, with a median improvement of 1 (p<0.05) and 3 (p<0.05) respectively (Figure 1). The mPDAI remission rate was 49% at week 8 with an mPDAI response rate of 73%. Endoscopic responders exhibited significant improvements in endoscopic oedema, granularity, friability, and mucous exudate (p<0.05). There was significant improvement in HRQoL, with the median SIBDQ score increasing from 35 at baseline to 54 at week 8 (p<0.05). Eleven patients received a further 8 weeks of therapy with a clinical response rate of 36%, yielding an overall response rate including extended induction of 67%. Univariate analysis did not reveal significant differences in baseline characteristics, clinical, or biochemical markers between responders and non-responders. However, a history of corticosteroid use (p=0.08) and high baseline levels of faecal calprotectin (p=0.15) demonstrated a non-significant association with treatment response. Elevated baseline serum levels of IL-1b, IFN-a and IL-33 were associated with a treatment response at week 8 (p<0.05).

Conclusion: Tofacitinib demonstrated preliminary efficacy in inducing both clinical and endoscopic response in patients with chronic pouchitis who have undergone IPAA for UC.

Emi Khoo

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