Mesalamine foam enema versus mesalamine liquid enema in active left-sided ulcerative colitis

To determine in a noninferiority study whether mesalamine foam is as effective as mesalamine liquid enema for inducing clinical remission in patients with active left-sided ulcerative colitis (UC).

In a multicenter investigator-blind trial, 375 patients with mild-to-moderate UC were randomized to receive mesalamine foam 1 g/80 mL/day or mesalamine liquid enema 1 g/100 mL/day for 4 wk (W). Inclusion criteria were: disease extension at least 5 cm from anorectal junction and not above splenic flexure and Clinical Activity Index (CAI) 1-4 > or = 4. Primary end point was clinical remission at W4 defined as a CAI 1-4 < or = 2. Noninferiority of the foam to liquid enema was declared if the lower limit of the 97.5% unilateral confidence interval (97.5% CI) of the difference in remission rates between foam and liquid enema groups was greater than -15% .

Remission rates at W4 in foam versus liquid were 68.3%versus 73.6% in per protocol (PP) population (lower limit of 97.5% CI -15.1%) and 66.7%versus 70.5% in intention-to-treat (ITT) population (97.5% CI -13.4%). Remission rates at W2 were 48.1 %versus 50.6% in ITT (97.5% CI -12.8%) and 49.1%versus 52.1% in PP (97.5% CI -13.8%) in foam versus liquid, respectively. Both treatments were well tolerated.

A 4-wk treatment of 1 g mesalamine foam induced a clinical remission in 68% patients versus 73% with 1 g mesalamine liquid enema. Although the noninferiority of mesalamine foam could not be strictly demonstrated at W4 in the PP analysis, it was achieved in the ITT population and at W2 in both populations. Mesalamine foam represents a therapeutic alternative to mesalamine liquid enema in patients with mild-to-moderate active proctitis and proctosigmoiditis.