"In recent years, the variations of pharmaceutical products in efficacy and safety among different geographic regions due to ethic factors is a matter of great concern for sponsors as well as for regulatory authorities. However, the key issues lie on when and how to address the geographic variations of efficacy and safety for the product development. To address this issue, a general framework has been provided by the ICH E5 (1998) in a document titled "Ethnic Factors in the Acceptability of Foreign Clinical Data" for evaluation of the impact of ethnic factors on the efficacy, safety, dosage, and dose regimen. The ICH E5 guideline provides regulatory strategies for minimizing duplication of clinical data and requirements for bridging evidence to extrapolate foreign clinical data to a new region. More specifically, the ICH E5 guideline suggests that a bridging study should be conducted in the new region to provide pharmacodynamic or clinical data on efficacy, safety, dosage, and dose regimen to allow extrapolation of the foreign clinical data to the population of the new region. However, a bridging study may require significant development resources and also delay availability of the test medical product to the needed patients in the new region. To accelerate the development process and shorten approval time, the design of multiregional trials incorporates subjects from many countries around the world under the same protocol. After showing the overall efficacy of a drug in all global regions, one can also simultaneously evaluate the possibility of applying the overall trial results to all regions and subsequently support drug registration in each of them"--Provided by publisher.