Question: In patients with Crohn colitis or ileocolitis, is olsalazine more effective than placebo in maintaining remission?
Design: Randomized (unclear allocation concealment*), blinded (unclear),* placebo-controlled trial with 52-week follow-up.
Setting: 25 hospitals in 3 countries.
Patients: 328 patients who were ≥ 18 years of age and had Crohn colitis or ileocolitis in complete remission (Crohn disease activity index [CDAI] ≤ 150) for ≥ 1 month before randomization. Exclusion criteria were receipt of steroid, azathioprine, or other immunosuppressive therapy within 8 weeks of the start of treatment; antibiotic therapy ≥ 1 month; potential for pregnancy or lactation; clinically important hepatic or renal insufficiency; strictures causing obstruction; fistulae; oral or symptomatic anal Crohn disease; stoma or small-bowel disease other than terminal ileal disease; or hypersensitivity to salicylates. 327 patients (99.7%) (mean age 39 y, 54% women) received the study drugs and had follow-up data.
Intervention: Patients were allocated to olsalazine, 2 g daily (n = 167), or placebo (n = 161) for 52 weeks.
Main outcome measures: The primary outcome was relapse (CDAI score > 150). Adverse events were also assessed.
Main results: The groups did not differ for relapse {P = 0.49}† (Table). The study was powered to detect a difference in relapse rate of 15%. The failure rate (patients not completing the study) was higher in the olsalazine group than in the placebo group (P = 0.038) (Table). Adverse events were mild to moderate in severity, but occurred in more olsalazine than placebo recipients (P = 0.035) (Table).
Conclusion: In patients with Crohn colitis or ileocolitis, olsalazine was not better than placebo in maintaining remission.
Olsalazine vs placebo for Crohn colitis or ileocolitis at 52 weeks‡
| Outcomes | Olsalazine | Placebo | RRI (95% CI) | NNH (CI) |
| Relapse | 48.5% | 45.0% | 8.5% (−37 to 14) | Not significant |
| Failure to complete study | 66% | 53% | 23% (3.1 to 48) | 9 (5 to 55) |
|
≥ 1 adverse event | 39% | 28% | 42% (3.7 to 95) | 9 (5 to 84) |