Aminosalicylates for induction of remission or response in Crohn's disease

Abstract

Background: Controlled clinical trials investigating the efficacy of aminosalicylates for the treatment of mildly to moderately active Crohn's disease have yielded conflicting results. A systematic review was conducted to critically examine current available data on the efficacy of sulfasalazine and mesalamine for inducing remission or clinical response in patients with mildly to moderately active Crohn's disease.

Objectives: To evaluate the efficacy of aminosalicylates compared to placebo, corticosteroids, and other aminosalicylates (alone or in combination with corticosteroids) for the treatment of mildly to moderately active Crohn's disease.

Search strategy: Separate MEDLINE (1966-July 2010), Cochrane Central Register of Controlled Trials (CENTRAL; Issue 3, 2010) and EMBASE database searches (1985-July 2010) of all relevant English and non-English language articles were performed, followed by manual searches of the reference list from potentially relevant papers and review articles, as well as proceedings from annual meetings (1991-2010) of the American Gastroenterological Association (AGA) and American College of Gastroenterology (ACG).

Selection criteria: Randomized controlled trials that evaluated the efficacy of sulfasalazine or mesalamine in the treatment of mildly to moderately active Crohn's disease compared to placebo, corticosteroids, and other aminosalicylates (alone or in combination with corticosteroids) were included.

Data collection and analysis: Data extraction and assessment of methodological quality of each selected study was independently performed by the investigators and any disagreement was resolved by discussion and consensus. The primary outcome measure was a well defined clinical endpoint of induction of remission or response to treatment. Nineteen studies met the inclusion criteria and were analyzed. Pooled relative risks (RR) for inducing remission or clinical response and their 95% confidence intervals were calculated (random effects model) where appropriate.

Main results: Sulfasalazine was more likely to induce remission (RR 1.38; 95% CI 1.02 to 1.87; n = 263) compared to placebo with benefit confined mainly to patients with colitis. Sulfasalazine was less effective than corticosteroids (RR 0.66; 95% CI 0.53 to 0.81; n = 260). Olsalazine was less effective than placebo in a single trial. Low dose mesalamine (1 to 2 g/day) was not superior to placebo (RR = 1.46, 95% CI 0.89-2.40; n = 302) and was less effective than corticosteroids. High dose mesalamine (3 to 4.5 g/day) was not superior to placebo for induction of remission (RR 2.02; 95% CI 0.75 to 5.45) or response (Weighted Mean Difference -19.8 points; 95% CI -46.2 to 6.7; n = 615). In a single randomized controlled trial, 5-ASA was inferior to budesonide (RR 0.56; 95% CI 0.40 to 0.78). No statistically significant difference was found between high dose mesalamine and conventional corticosteroids (RR 1.04; 95% CI 0.79 to 1.36; n = 178). However, relatively few patients were available for analysis. There was a lack of good quality clinical trials comparing sulfasalazine with other mesalamine formulations.

Authors' conclusions: Sulfasalazine has modest efficacy compared to placebo and is inferior to corticosteroids for the treatment of mild to moderately active Crohn's disease. Olsalazine and low dose mesalamine (1 to 2 g/day) are not superior to placebo. High dose mesalamine (3 to 4.5 g/day) is not more effective than placebo for inducing response or remission. High dose mesalamine was inferior to budesonide for inducing remission in a single trial. In conclusion, sulfasalazine shows modest efficacy for the treatment of active Crohn's disease. However, the existing data show little benefit for 5-aminosalicylates.