This paper discusses four methodological topics that have been a regular source of difficulty and debate in European regulatory work. (i) The increasing use of non-inferiority trials in the development of medicinal products has highlighted several problems. These relate first to the choice of the non-inferiority margin and secondly to the circumstances under which a non-inferiority design is or is not appropriate. (ii) The use of meta-analysis in regulatory applications is still controversial and acceptable uses need to be defined. (iii) Analysis of responders provides a useful insight into the size of treatment benefits but can be misleading, especially when it is impossible to be certain whether or not an individual patient has truly responded to treatment. (iv) The extent of the monitoring of clinical trial procedures and data still distinguishes industry-sponsored trials from other trials: it is not clear that it should. These questions are all equally important for those involved in clinical trial work outside the arena of pharmaceutical development.

Copyright 2002 John Wiley & Sons, Ltd.