Pitfalls in designing trials of functional dyspepsia: the ascent and demise of itopride
- Dr S Veldhuyzen van Zanten, Division of Gastroenterology, University of Alberta, Zeidler Ledcor Centre, Edmonton, Alberta T6G 2X8, Canada;
The publication in this issue of Gut (see page 10.1136/gut.2007.132449) of the results of the clinical trial programme evaluating itopride in functional dyspepsia (FD)1 needs to be applauded on two counts:
Axcan Pharma, the sponsor of the study for conducting this comprehensive clinical trial programme.
Gut for publishing data that are important despite the overall disappointing results of the studies.
Over the last 15 years, definite progress has been made in the design, execution and data analysis of FD treatment trials. The efficacy of a limited number of treatment options has also been established. There is evidence that proton pump inhibitors (PPIs), and to a lesser extent H2 receptor antagonists (H2RAs), are efficacious in a proportion of FD patients.2–5 Importantly, the presence of heartburn appears to be a predictor of response.2 As a result, there is debate as to whether this is due to the inclusion of patients with unrecognised gastro-oesophageal reflux disease (GORD) symptoms rather than “true” FD patients.6 Consequently, there is a school of thought that non-response to a PPI should be a diagnostic criterion for a diagnosis of FD. In a small proportion of Helicobacter pylori-positive FD patients, cure of the infection will lead to a sustained improvement in symptoms with an estimated number needed to treat to obtain one success of 14.4 5 7
There has been a longstanding interest in the use of prokinetics, especially cisapride, as a treatment for FD. Unfortunately many of the cisapride studies suffered from poor study design, and there is evidence that this tended to overestimate treatment efficacy.4 5 8
Furthermore, it is possible that part of the response seen with cisapride in FD may have been related to associated heartburn symptoms.8 A systematic review on the …