Oral 5-aminosalicylic acid for induction of remission in ulcerative colitis.

BACKGROUND

The newer 5-ASA preparations were intended to avoid the adverse effects of SASP while maintaining its therapeutic benefits. The efficacy and safety of 5-ASA preparations have been evaluated in numerous clinical trials that have often lacked sufficient statistical power to arrive at definitive conclusions. Previously, it was found that newer 5-ASA drugs in doses of at least 2 g/day, were more effective than placebo but no more effective than SASP in inducing remission in ulcerative colitis. This updated review includes more recent studies and evaluates the effectiveness, dose-responsiveness, and safety of 5-ASA preparations in terms of more precise outcome measures.

OBJECTIVES

To assess the efficacy, dose-responsiveness and safety of the newer release formulations of 5-aminosalicylic acid (5-ASA) compared to placebo or sulfasalazine (SASP) for the induction of remission in active ulcerative colitis.

SEARCH STRATEGY

A computer-assisted literature search for relevant studies (1981-2005) was performed using MEDLINE, BIOS, the Cochrane Controlled Trials Register, the Cochrane IBD/FBD group specialized trials register and the Science Citation Index, followed by a manual search of reference lists from previously retrieved articles, review articles, symposia proceedings, and abstracts from major gastrointestinal conferences.

SELECTION CRITERIA

Studies were accepted for analysis if they were randomized, double-blinded, and controlled clinical trials of parallel design, with treatment durations of a minimum of four weeks.

DATA COLLECTION AND ANALYSIS

Based on an intention to treat principle, the outcomes of interest in the treatment of active disease were the failure to induce global/clinical remission, global/clinical improvement, endoscopic remission, or endoscopic improvement.

MAIN RESULTS

5-ASA was superior to placebo with regard to all measured outcome variables. For the failure to induce global/clinical improvement or remission, the pooled Peto odds ratio was 0.40 (95% CI, 0.30 to 0.53). A dose-response trend for 5-ASA was also observed. When 5-ASA was compared to SASP, the pooled Peto odds ratio was 0.83 (95% CI 0.60 to 1.13) for the failure to induce global/clinical improvement or remission, and 0.66 (95% CI 0.42 to 1.04) for the failure to induce endoscopic improvement. SASP was not as well tolerated as 5-ASA.

AUTHORS' CONCLUSIONS: The newer 5-ASA preparations were superior to placebo and tended towards therapeutic benefit over SASP. However, considering their relative costs, a clinical advantage to using the newer 5-ASA preparations in place of SASP appears unlikely. This review updates the existing review of oral 5-aminosalicylic acid for induction of remission in ulcerative colitis which was published in the Cochrane Library (Issue 1, 2006).