Clinical trials for drug registrations in Asian-Pacific countries: proposal for a new paradigm from a statistical perspective.

The world has become more interdependent in the movement of free trade and global markets. The regulations for approval of new drugs in the Asian markets have always been an important issue in the free trade negotiation between the U.S.- and E.U.-based international manufacturers and the Asian-Pacific countries, since pharmaceuticals are of large trade value for them. In 1998 the University of Hong Kong and the Singapore National Medical Research Council jointly hosted the first Asian Clinical Trials Conference. The Society for Clinical Trials was invited as a collaborator for the event, which signified a milestone for interaction between the East and West in the discussion of clinical trials. Many have participated in the discussion of drug approval and registration issues for the Asian region based on the drug development experience in the United States. However, there are many interesting differences between the two regions, which lead to different approval processes for new drugs developed by the U.S.- and E.U.-based international manufacturers. This article highlights some regulatory dilemmas and some key statistical concepts pertinent to these differences. The purpose of this paper is to resolve the regional regulatory and scientific dilemma. A new paradigm of sample size design and data analysis for drug approval for countries in the Asian-Pacific region is proposed. The central premise is that substantial information from multicenter studies has already shown efficacy in the United States or the European Union when a drug manufacturer seeks marketing approval in an Asian country. This leads to the idea of a "consistency trial" using the method of Bayesian most plausible prediction. The method is illustrated with an example.