• irritable bowel syndrome
• tegaserod
• Asia-Pacific
• double blind study

Until recently, there existed little evidence that any therapy was effective for irritable bowel syndrome (IBS). The quality of clinical trials was poor,^1,2 and no systematic review^3,4 can redeem faulty data.⁵ Mindful of this, pharmaceutical companies now employ modern clinical trial principles to test IBS drugs. The latest of these efforts is an Asia-Pacific randomised controlled trial of tegaserod by Kellow et al, described in this issue of Gut⁶ [see page 671].⁶ To judge how well tegaserod matches the needs of IBS patients we must examine the trial methods, results, and conclusions, and divine what is missing from the reports.

The Asia-Pacific study is similar to Western IBS trials of tegaserod.^7,8 These represent substantial improvements in trial methodology. The entered subjects had criteria defined IBS and most had a “non-diarrhoea” bowel habit suitable to the drug’s effects. Recruitment was sufficient to show definitive results, and subjects were double blinded and randomly allocated. A primary global outcome was selected with appropriate secondary measures, and the analysis was “intention to treat”. Primary outcome differences were consistently significant at the pre-decided end point, and over 12 weeks. Tegaserod appears safe (sine qua non for IBS), and post-marketing surveillance should detect unexpected adverse effects.

The Kellow study achieved greater therapeutic gain (absolute benefit increase) than prior tegaserod studies (21% v 11.8%⁷ and …