Clinical trial: Randomized-controlled clinical study comparing the efficacy and safety of a low-volume vs. a high-volume mesalazine foam in active distal ulcerative colitis

Background: Rectally administered mesalazine (mesalamine; 5-aminosalicylic acid) is the first-line therapy for treatment of distal ulcerative colitis. Recently, a high-volume 5-aminosalicylic acid foam has been shown to be as effective and safe as standard 5-aminosalicylic acid enema. Aim: To study the efficacy and safety of a low-volume vs. a high-volume 5-aminosalicylic acid foam. Methods: In this investigator-blinded study, patients with active distal ulcerative colitis [Clinical Activity Index (CAI) > 4, Endoscopic Index ≥ 4] were randomized to receive 2 × 1 g/30 mL low-volume (n = 163) or 2 × 1 g/60 mL high-volume 5-aminosalicylic acid foam (n = 167) for 42 days. Primary end point was clinical remission (CAI ≤ 4) at the final/withdrawal visit (per-protocol). Results: 330 patients were evaluable for efficacy and safety by intention-to-treat, 290 for per-protocol analysis. Clinical remission rates at week 6 (per-protocol) were 77% on low-volume foam vs. 77% on high-volume foam (P = 0.00002 for non-inferiority). The low-volume foam was associated with a lower frequency of severe discomfort, pain and retention problems. Conclusions: Low-volume 5-aminosalicylic acid foam is as effective and safe as a high-volume 5-aminosalicylic acid foam in the treatment of active distal ulcerative colitis, but offers compliance advantages compared to the high-volume preparation.