An enema formulation of alicaforsen, an antisense inhibitor of intercellular adhesion molecule-1, in the treatment of chronic, unremitting pouchitis

Background: Pouchitis is the major long-term complication of ileal pouch-anal anastomosis for ulcerative colitis. The incidence of pouchitis is as high as 50% several years after surgery. Two-thirds of pouchitis patients suffer recurrence. Of those who recur, one-quarter suffer from chronic, unremitting pouchitis. Current treatments for this disorder are disappointing. Aim: To determine whether a topically administered enema formulation of ISIS 2302 (alicaforsen), an antisense inhibitor of intercellular adhesion molecule-1, can improve the clinical symptoms, endoscopic mucosal appearance and mucosal histology in patients with chronic, unremitting pouchitis, a disorder in which this molecule is over-expressed. Methods: In an open-label, uncontrolled study, 12 patients with chronic, unremitting pouchitis were treated with 240 mg alicaforsen antisense enema nightly for 6 weeks. Clinical evaluation and endoscopy were performed at baseline and at weeks 3, 6 and 10. Pouchoscopy with biopsy was carried out at baseline and at weeks 6 and 10. The primary end-point was the reduction from baseline of the Pouchitis Disease Activity Index (PDAI) at week 6. Secondary end-points included the PDAI at week 10. Safety was evaluated by analysing the adverse events, vital signs and laboratory parameters. Results: After 6 weeks of nightly alicaforsen enema, a statistically significant (n = 12, P = 0.001) reduction in the PDAT from baseline (11.42) to week 6 (6.83) was observed. Mean reductions in the endoscopy sub-score from baseline (5.25) to week 3 (3.08) and week 6 (2.58) were statistically significant (P = 0.0039 and P = 0.0005, respectively). The mean reductions in clinical symptom sub-score from baseline (3.75) to week 3 (2.33) and week 6 (2.25) were also statistically significant (P = 0.0156 and P = 0.0117, respectively). Ten of the 12 patients achieved a mucosal appearance score of 0 or I at endoscopy. Five of the 12 patients (42%) had a non-statistically significant decrease in the histology component of their PDAI from baseline to week 6. By week 6, seven of the 12 patients (58%) were in remission, as defined by PDAI < 7, with a mean decrease from baseline in PDAI score of six points. The alicaforsen enemas were well tolerated and no serious side-effects were noted. Conclusions: Antisense enema to intercellular adhesion molecule-1 is safe and well tolerated. In an open-label trial, it appeared to improve the PDAI score, clinical symptoms and endoscopic mucosal appearance. It may also improve the histology. In the light of the responses observed in this trial, a randomized, placebo-controlled trial is warranted.